After Life: Rot Box Detectives


After Life: Rot Box Detectives

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Inside this large, glass box,

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something extraordinary is happening.

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Food is being left to rot for eight weeks

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in our own unique laboratory.

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This is an investigation

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into nature's biggest and best recycler...

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..decay.

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And it's being done on a scale that has never been tried before.

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I'm Dr George McGavin. I'm a biologist with a particular passion for insects.

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The Rot Box detectives, Iona, Rosie,

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Ruaridh, Mram and Jamie

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are going to help me investigate the amazing world of rot and decay.

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'There's bacteria...'

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MACHINE BLEEPING

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Look at that. That really is smelly.

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'..flies...'

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I want to show you the fish. It's been completely eaten out.

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'..and mould.'

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20 or 30 species of fungus?!

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At Rot Box Detective HQ, I'm meeting up with the team.

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-Hi, team.

-ALL: Hi.

-How do you think we made the Rot Box?

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-Great difficulty.

-Yeah, it was quite difficult actually.

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We wanted to make a typical kitchen and garden

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and fill it full of the sort of food you'd have

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if you were having a party.

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We wanted it quite warm, as if it was a hot summer's day

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and we wanted quite humid as well.

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So why do you think we did that?

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The bacteria would come

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because the hotter it is, like if you left a drink out

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for ages, it would go all warm and horrible.

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Exactly. The hotter it is, the faster things happen.

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-All organisms need some form of...?

-Water.

-Water, yes. Exactly.

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So the best conditions for bacteria and fungi

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are hot and sweaty, basically.

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The hotter it is, the faster things rot.

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This giant Rot Box has taken a team of engineers

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and scientists eight months to design and build.

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Conditions inside are now perfect for rot to begin.

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It's hot, humid and there's plenty of air

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so it doesn't take long for the mould to take hold

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and begin breaking down the food.

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By only the second day, there are dramatic changes inside.

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'It's really warm in here,'

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it's 25 degrees. That's like a warm summer day,

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so some things are drying out

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the chilli con carne is already growing a layer of mould.

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That shows there are fungal spores drifting around in the atmosphere

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and settling on food. Over here, the sandwiches

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which originally filled the box,

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up to the top, have sagged down to about half their height.

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-I think it's a fish.

-I thought that was the fish.

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There's two fishes.

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-Eurgh, what's that?

-Oh!

-Where was it?

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-There. It's a dead mouse.

-Eurgh!

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Disgusting!

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The Rot Box Detectives are intrigued and excited by what they see.

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It's time for them to start their own investigations.

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Who knows what an experiment is?

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It's an experiment when you judge something by something else

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and you see the difference maybe.

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Yeah, pretty close.

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If you have a question and you want to find the answer.

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Exactly. It's a controlled test that helps you to see

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if a question you ask is correct or not.

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So how would you design an experiment to investigate

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the effect of temperature on how fast things rot?

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Heat and cold.

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OK, so we have one hot environment and one cold one,

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which is a fridge and the airing cupboard. That's our variable.

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So what will we have to put in those two environments?

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-Something that will...

-Rot.

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Yes! Something that will rot.

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So what sort of things do you think are going to rot easily?

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-Fruit and bread.

-Fruit and bread, yeah.

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-Which do you think would grow the most mould?

-I would say the bread.

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-Yeah.

-Apples.

-Apples, OK.

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Peppers, because in the Rot Box they were all really black and crispy.

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OK, so you've got all these things. What are you going to put them in?

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-Do you think you could put them in a glass box.

-Yeah, OK.

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So you can each have two boxes, one will go in the fridge,

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the other in the airing cupboard where it's warm.

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We've got one variable, which is if it's hot or cold.

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-Everything else should be the same. Why?

-Because it's a fair test.

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Absolutely. It has to be a fair test.

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If you don't have the same things, it's not fair.

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-How does bacteria get into it?

-Good question.

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Well, bacteria is everywhere in the environment.

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We have bacteria all over our hands, even after you've washed them.

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There's bacteria all over this box,

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so the bacteria and the fungi are there,

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we just encourage them to grow.

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Our big Rot Box is also full of bacteria.

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In a matter of hours, they have started to do their work.

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The clearest signs of change are on the chicken.

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In just one day, our time lapse cameras

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show these blotches appearing on its skin,

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I've asked Dr Clare Taylor, a microbiologist, to join me

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and explain what's happening.

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Well, Clare, that chicken is beginning to look

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pretty discoloured.

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It smells a bit as well.

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There's beginning to be a slight whiff. What have you got on this?

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I tell you what I've got a UV light

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so we can take a look more closely at the surface.

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-Now you can't see it.

-No, can't see anything.

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Take a look at that!

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It's glowing! So all these areas are glowing sort of blue.

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Exactly, so where you can see those glowing bits, that's bacteria.

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So even though we can't see them, bacteria are everywhere.

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They're all around us.

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'Now the team and I are going to make our own mini Rot Boxes.'

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LAUGHTER

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Right, two each. Pass them down.

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Two for you, two for you.

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Right, you can put whatever you want in the box,

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as long as both boxes are exactly the same.

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I thought it might be interesting to have one inanimate object,

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like a bolt or something.

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-Will that rot?

-No.

-Why won't it rot?

-Because it's a metal object.

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It's metal, yeah, It isn't alive, is it?

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Fill your boxes!

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So in order for it to be properly scientific,

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we need to write down our names on a piece of paper, the date,

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and describe what we did.

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We have to say what the experiment was supposed to do,

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and what our predictions for the outcome of the experiment is.

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When we take our boxes out of the refrigerator

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and the airing cupboard, we then write down our results, OK?

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'I think the metal thing might get rusty,

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'because when I see the railings they mostly get brown from silver.

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'So I think it might rust a little.

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'I think there will be less mould in the cold one.

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'It might have a little bit of bacteria and a little bit of mould.

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'I think the pepper will rot the most, because when we went to see

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'the Rot Box, in the fruit bowl, the peppers were absolutely disgusting.

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'I don't think that the paper will go mouldy, but I think some

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'of the mould from the apple would probably go a bit onto the paper.

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'I think the potatoes will rot the quickest.'

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-I'm quite excited about this.

-Me too, yeah.

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It'll be really good, this experiment. Really interesting.

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We might even find some undescribed species of fungi or bacteria.

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Who knows? It could happen.

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Back at the big Rot Box,

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the Detectives continue to be amazed by the world of decay.

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But will they see similar results in their mini Rot Boxes?

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Their experiment tests how temperature affects

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the speed of rot. They filled two boxes

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with exactly the same foods. The only variable is temperature.

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One box is in a hot place and one box is in a cold place.

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It's a fair test.

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They've recorded what they did, how they did it

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and what they think might happen.

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What will the detectives discover?

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Inside this large, glass box,

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something extraordinary is happening.

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Food is being left to rot for eight weeks

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in our own unique laboratory

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This is an investigation

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into nature's biggest and best recycler...

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..decay.

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And it's being done on a scale that has never been tried before.

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I'm Dr George McGavin. I'm a biologist with a particular passion for insects.

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The Rot Box detectives, Iona, Rosie,

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Ruaridh, Mram and Jamie

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are going to help me investigate the amazing world of rot and decay.

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'There are flies...'

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Well, there are simply too many flies in here.

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It's becoming quite unpleasant.

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'..bacteria...'

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-Oho!

-Take a look at that.

-It's glowing!

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'..and mould.'

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Even the hamburgers are wrapped up and they're covered in mould. Ooh!

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That might blow at any time.

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Pass them down. Two for you...

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'Four weeks ago, the Rot Box Detectives built their own

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'mini Rot Boxes so they could examine rot

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'more closely for themselves.'

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They wanted to see how temperature affects the speed of rot,

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so they designed a test, an experiment to find the answer.

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They had two boxes each and filled each box with the same things.

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To make the test fair,

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everything was the same except for one variable, which was temperature.

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They wrote down their hypothesis, what they thought would happen.

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I think there'll be less mould in the cold one than the hot one.

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It might have a little bit of bacteria.

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'Scientists often work in laboratories,

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'so we've come along to one to examine the results

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'of our four-week-old Rot Boxes.'

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I want you to meet a friend of mine called Patrick, who's a mycologist.

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That's an expert on fungi.

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Now we can only open the boxes because we're in a lab

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and because Patrick here is a specialist in fungi.

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He will tell us if there's anything harmful to us in these boxes.

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-I suspect there isn't anything that's that harmful.

-It's unlikely.

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As long as we don't sniff or inhale them or eat them, touch them

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and put our fingers in our mouths, we should be fine.

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I know it's going to be very hard for you to resist,

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with your fingers touching things,

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so I think we should all put on gloves.

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OK, let's open the cold box first. So this is Ruaridh's one.

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Well, I can see there is a little bit of mould on the bread there.

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Penicillin probably.

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But everything looks as it would do when it's been fairly freshly made.

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None of it's gone mushy or soggy.

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We'll open the one that's been in the warm temperature.

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-Ooh!

-CHILDREN: Eurgh!

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-That's very different, isn't it?

-The bread has completely gone down

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to a kind of soggy mess.

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The apple looks like it's been poached or something.

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Ruaridh, you've at least shown what you thought was going to happen.

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There's more fungus growing in your hot box, but you were right

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about there being a little bit of fungus in your cold one.

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So this is Jamie's box.

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-Was the bread already this size?

-I don't think it was.

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I think it's shrunken down.

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Why are the bananas pushed in?

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The fungus has taken the moisture out of the banana

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and used it for itself. It's shrunken right down.

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The fungi on my mushroom looks different than the other ones.

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OK, so we have a comparison.

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Fungi often changes depending on what part in their life cycle.

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Sometimes they can change colour in a few days.

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That one's plain white and that one's really bubbly.

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-Is that hard or soft, the mould on there?

-Really soft.

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-It's breaking down.

-Looks like a marshmallow.

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It is just like a marshmallow actually.

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That's the fungal mould that's growing through there.

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Would you say there's anything edible in any of the hot boxes?

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Let's have a look and see.

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No, it's all soft and horrible.

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Because we cut the oranges,

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the fungi and bacteria have got inside them and broken them down.

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But if you had a whole orange in there, it might not rot down.

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But you should still never eat anything in these experiments.

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Back at the big Rot Box,

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Patrick and I are staggered by what we discover.

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Now, this to my, Patrick,

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is one of the most amazing things I've ever seen.

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Look at it! I mean, that was a pile of cheese

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and tomato sandwiches that was up to the top of the box.

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-How many actual species of fungus are here?

-Oh, at least 20 or 30.

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-Maybe more.

-20 or 30 species of fungus?!

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-Look at that. I mean, it's a solid mat.

-Oh, yeah.

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There are the layers of sandwich.

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It's all the way through, it's completely through.

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There aren't many flies here, of course.

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Yeah, it was sealed in the box so the flies couldn't get in.

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Big contrast there to the fruit bowl which was left open.

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A couple of weeks ago, it was really covered in thick layers of fungus.

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-Look at the fly.

-The flies have stripped it bare.

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The flies have gone in there, they've eaten the fungus,

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eaten the spores and really just recycling the fungi.

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Moulds are masters of decay.

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They're a form of fungi, the most versatile

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and important decomposers on the planet.

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Fungi can grow on almost anything.

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In our box, moulds are attacking our fruit and vegetables

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and spread by releasing spores into the air which are like seeds.

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They find new places to settle and grow,

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overwhelming everything in their path, even our meat.

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There are up to 500 spores in every cubic metre of air in your home.

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But they're so small, you can only see them with a microscope.

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Whoa.

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It looks like snow.

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It looks like the fluff on my teddy bear or something like that.

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The white looks like the Antarctic.

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Now this microscope only magnifies things about 100 times.

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But in the Rot Box,

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we had a microscope that could magnify stuff by 7,000 times.

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I want you to take a look at some of the fungi we filmed there.

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This is the kind of mould you might find in your bread,

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magnified by 7,000 times.

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The thread-like stalks are ten times finer than a human hair.

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The fluffy ball shapes at the top are where the spores live.

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Much like dandelion seeds,

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the spores are released into the air and carried to new places to grow.

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You might not always be able to see it, but mould is everywhere.

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Your house alone may contain an unbelievable 1,000 different

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types of mould.

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Patrick, thanks very much.

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It's been a real thrill to be able to use your lab and your expertise.

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-I'm sure we've learned quite a lot, haven't we?

-Yeah.

-So thank you very much.

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Back inside the big Rot Box, mould continues to astound and amaze.

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The Rot Box Detectives have grown their own fantastic fungi

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in their mini Rot Box experiments.

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They found that there was more mould in the hot box than the cold box.

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This is because mould grows faster in warm conditions

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than in cold conditions.

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They prove that their hypothesis,

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which is what they thought might happen, was correct.

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Inside this large, glass box,

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something extraordinary is happening.

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Food is being left to rot for eight weeks

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in our own unique laboratory.

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This is an investigation into nature's biggest and best recycler...

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decay.

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And it's being done on a scale that has never been tried before.

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I'm Dr George McGavin.

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I'm a biologist with a particular passion for insects.

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The Rot Box detectives, Iona, Rosie, Ruaridh, Mram and Jamie

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are going to help me investigate the amazing world of rot and decay.

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'We'll see flies...'

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The burgers that were opened are riddled with maggots.

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'..mould...'

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It's almost a battle zone in your bread bin.

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'..and bacteria.'

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I wonder how many bacteria are on that.

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At Rot Box Detective HQ, we're investigating some really bad smells.

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I've got a challenge for you.

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How can you tell if food is safe to eat, if it's off,

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without actually tasting it?

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Because of the smell?

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Smell is a very good clue.

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Maybe from its looks, because sometimes you see the bread is white,

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and sometimes it's green. So you can spot the difference between them if it's rotten or not.

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Mm-hm. If a food smells funny, or off,

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or if it looks peculiar, that's a really good warning sign, isn't it?

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Well, I've brought some items along for you to smell. See if you think they're off.

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Here's the first one.

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Cheese. What do you think of that?

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-That's all right.

-Urgh!

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I don't think it's off.

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It's strong but I wouldn't say it's off.

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It's not off, but it smells really, really strong.

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Yeah, it's strong, but it's not a lot to...

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Let's try... Now, don't smell this one, OK?

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It's mouldy bread, so you don't have to smell it.

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Very mouldy, isn't it?

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If you found that in your bread bin,

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-you wouldn't want to put that in your toaster, would you?

-No,

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you'd be mad to eat that.

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Dark green, yellow...

0:21:140:21:17

Yellow in the bottom...

0:21:170:21:19

It's mostly green on the top.

0:21:190:21:22

Eugh!

0:21:220:21:23

It looks like a sponge you use for washing the dishes!

0:21:230:21:27

HE LAUGHS

0:21:270:21:29

Now, I've got an extra special treat -

0:21:290:21:31

I've brought you your lunch. Have a good smell of that. That's fish.

0:21:310:21:35

Urgh!

0:21:350:21:36

That's disgusting!

0:21:360:21:39

Oh! Ho, ho!

0:21:410:21:43

HE CHOKES

0:21:430:21:44

That is...

0:21:440:21:47

Eugh!

0:21:470:21:49

THEY LAUGH

0:21:490:21:52

Anyone else want an extra smell?

0:21:520:21:54

THEY LAUGH AND SHRIEK

0:21:540:21:56

The reason this smells SO bad

0:21:580:22:00

is it's loaded with bacteria

0:22:000:22:02

that have all been developing in there,

0:22:020:22:04

and they're producing toxins and gases,

0:22:040:22:07

and that really dreadful smell

0:22:070:22:10

is warning you that that's really off. You wouldn't eat this

0:22:100:22:13

in a million years, would you?

0:22:130:22:16

-If it was the last thing on earth.

-If it was the last thing on earth...

-GIGGLING

0:22:160:22:21

There is an overpowering stench inside the giant Rot Box, too,

0:22:240:22:29

as the bacteria breaks down the food

0:22:290:22:32

which has now been decaying for two days.

0:22:320:22:34

Let's take a closer look at them under the microscope.

0:22:340:22:39

This bacterium, Pseudomonas, magnified 7,000 times,

0:22:390:22:43

is the most common type of food-rotting bacteria.

0:22:430:22:48

There are as many as a trillion individual bacterial cells

0:22:480:22:53

in this sample alone.

0:22:530:22:56

We can't see bacteria without a microscope,

0:22:560:22:59

but they're absolutely everywhere.

0:22:590:23:02

They're the most common agent of decay on the planet.

0:23:020:23:06

They're the first to attack dead animals

0:23:060:23:09

because they're already living on them.

0:23:090:23:12

All creatures carry bacteria.

0:23:120:23:15

These bacteria were on our chicken when it was alive,

0:23:150:23:20

and now that it's dead,

0:23:200:23:22

they've quickly begun to decompose its flesh.

0:23:220:23:25

-Who can tell me something about bacteria?

-They're small.

-Very small.

0:23:330:23:39

-You need a microscope to see them.

-You do need a microscope.

0:23:390:23:43

In fact, here is a teaspoonful of soil.

0:23:430:23:46

How many bacteria do you think are in that teaspoonful of soil?

0:23:460:23:49

-Over a million?

-There are 40 million bacteria in that amount of soil.

0:23:490:23:54

It's hard to see them, but it's easier to see what they do,

0:23:540:23:57

and on here, I've got a film of a chicken that we put in the Rot Box.

0:23:570:24:02

Now, look at this. Watch this.

0:24:020:24:07

-THEY ALL GASP

-What's going on there?

0:24:070:24:10

-It's blowing up.

-Like a balloon.

0:24:100:24:12

It's blowing up like a balloon.

0:24:120:24:14

That was a fresh chicken, a completely fresh chicken,

0:24:140:24:17

but any piece of fresh meat has bacteria on it,

0:24:170:24:21

and because we just left that in the open, the bacteria grew and grew.

0:24:210:24:26

Some of these bacteria are really quite hazardous,

0:24:260:24:29

so if you ate uncooked meat, you'd be quite ill.

0:24:290:24:32

So, with all these bacteria around, how can you make food safe?

0:24:320:24:36

-You can refrigerate it.

-Yeah.

0:24:360:24:38

-You could cook it and then put it back in the fridge.

-Absolutely.

0:24:380:24:42

-What do organisms need to grow?

-Water!

-Water, yeah. OK.

0:24:420:24:47

So you could dry it, you could freeze it,

0:24:470:24:51

you could heat it up, if it's cooked.

0:24:510:24:54

-Would cooking a chicken make it safe for ever?

-ALL: No.

-No, it wouldn't.

0:24:540:24:59

-Because it would eventually rot, as well.

-Yeah.

0:24:590:25:03

So it's all about slowing down the bacterial growth, isn't it?

0:25:030:25:08

In the Rot Box, we had the ideal environment for growing bacteria.

0:25:080:25:12

It was hot, it was humid, and there was air,

0:25:120:25:15

so bearing that in mind, I want to set you a challenge.

0:25:150:25:18

I'm going to divide you into two teams

0:25:180:25:21

and you're going to a supermarket to find different foods

0:25:210:25:25

that have been preserved in different ways. OK?

0:25:250:25:27

-Are you up for that?

-ALL: Yes!

0:25:270:25:30

What's in that? That's good.

0:25:420:25:44

CHILDREN CHATTER

0:25:440:25:46

-So what shall we get?

-We need something sealed, tinned, boxed...

0:25:460:25:52

-I think it looks good.

-Yeah.

0:25:520:25:54

Frozen - ah, here we are!

0:25:590:26:02

Oh, cans! Yeah.

0:26:020:26:04

On the hunt for baked beans.

0:26:040:26:06

There we are. Right.

0:26:060:26:08

Done!

0:26:080:26:10

Let's start with the girls' team. What have you got?

0:26:110:26:14

-Vacuum-packed coffee.

-And that's preserved because...?

-No air.

0:26:140:26:20

There's no air, so that'll slow the bacteria down.

0:26:200:26:22

-What else have you got?

-Dried mango.

0:26:220:26:26

There's no water in it so, again,

0:26:260:26:28

that'll stop the bacteria growing. Anything else?

0:26:280:26:31

-Gammon. There's no air and it was cold. It was in the fridge.

-OK.

0:26:310:26:38

It probably has preservatives in it, as well.

0:26:380:26:41

They add preservatives to make food last longer.

0:26:410:26:44

Good work, girls. Let's see what the boys have got.

0:26:440:26:47

-We've for croutons, which we bought because they were dry.

-Absolutely.

0:26:470:26:52

Dry as a bone in there. OK. What next?

0:26:520:26:55

Olives, cos they're in water,

0:26:550:26:58

and when they're in water, we thought the bacteria would slow down

0:26:580:27:03

because we've never seen rotten olives before.

0:27:030:27:07

Water's not going to be good because that'll encourage bacterial growth.

0:27:070:27:11

It's actually olive oil in here, and it's been vacuum-packed as well,

0:27:110:27:16

so if you keep that shut, it should stay fresh - or not rot -

0:27:160:27:21

for quite a long time.

0:27:210:27:22

We got baked beans, because they're tinned

0:27:220:27:26

and it would be harder for the bacteria to go in

0:27:260:27:31

because it's tinned.

0:27:310:27:34

So, unless you open that can,

0:27:340:27:37

it'll probably stay fresh for a very long time.

0:27:370:27:39

I am amazed that nobody picked frozen food,

0:27:390:27:44

one of the commonest ways of preserving food.

0:27:440:27:47

It's so cold no bacteria will grow in there. Or, if they do,

0:27:470:27:51

it'll be very, very slow indeed.

0:27:510:27:54

All these are brilliant techniques at slowing down

0:27:540:27:57

the growth of bacteria - you exclude water, you keep it cold

0:27:570:28:01

or you exclude air - so well done, everybody.

0:28:010:28:04

We can often tell when food isn't good to eat by looking at it

0:28:080:28:13

or smelling it.

0:28:130:28:15

It's easy to see mould at work.

0:28:150:28:17

We can't see bacteria,

0:28:170:28:19

because they're tiny organisms that can only be seen using a microscope.

0:28:190:28:24

But we can see the effects of what we do,

0:28:240:28:28

and we can smell the gases they produce when they're attacking food.

0:28:280:28:32

This should warn us not to eat it.

0:28:320:28:34

Bacteria are everywhere, and are already on foods like meat and fish

0:28:340:28:38

when you buy them.

0:28:380:28:40

They are the most common agents of decay on the planet.

0:28:400:28:44

Inside this large glass box,

0:28:510:28:54

something extraordinary is happening.

0:28:540:28:58

Food is being left to rot for eight weeks

0:28:580:29:01

in our own unique laboratory.

0:29:010:29:04

This is an investigation into nature's biggest

0:29:070:29:11

and best recycler - decay.

0:29:110:29:15

And it's being done on a scale that has never been tried before.

0:29:150:29:20

I'm Dr George McGavin.

0:29:200:29:22

I'm a biologist with a particular passion for insects.

0:29:220:29:26

The Rot Box detectives - Iona, Rosie,

0:29:260:29:30

Ruaridh, Mram and Jamie -

0:29:300:29:33

are going to help me investigate

0:29:330:29:36

the amazing world of rot and decay.

0:29:360:29:40

'We'll see flies...'

0:29:440:29:46

Oh. Oh-hoo!

0:29:460:29:47

Look at this.

0:29:470:29:49

'..mould...'

0:29:490:29:51

Ah! That's incredible.

0:29:510:29:53

'..and bacteria.'

0:29:530:29:55

The bacteria have been hard at work.

0:29:570:29:59

At Rot Box detective HQ, we're discovering more about bacteria.

0:30:020:30:08

Now, who can tell me something about bacteria?

0:30:080:30:11

-There's some good bacteria and some bad bacteria.

-True.

0:30:110:30:15

-They're absolutely everywhere.

-That is completely correct.

0:30:150:30:19

I went out to the garden earlier and I collected some rainwater.

0:30:190:30:22

There are one million bacteria just in that little spoonful there.

0:30:220:30:28

-One million!

-Wow.

-In there.

0:30:280:30:32

Now, the one thing about bacteria, of course, is, as you said,

0:30:320:30:35

there's good and bad ones.

0:30:350:30:38

What would happen if a bad bacterium had got inside you?

0:30:380:30:41

-You'd get a tummy bug.

-Absolutely.

0:30:410:30:45

How do you think the bacteria get inside you?

0:30:450:30:48

If you eat something but before you ate it, you didn't wash your hands.

0:30:480:30:53

Absolutely right. That is the commonest route to get internal infections,

0:30:530:30:58

internal bacteria.

0:30:580:30:59

Now, I've got a very smart trick that will show us

0:30:590:31:03

how easy it is to transfer bacteria from person to person to person.

0:31:030:31:08

OK?

0:31:080:31:09

Now, we can't see bacteria on our skin without very special equipment,

0:31:110:31:15

but I can show you how they spread around.

0:31:150:31:18

'I'm going to show the team how easy it is to spread bacteria

0:31:180:31:23

'by using this special cream that glows under ultraviolet light.'

0:31:230:31:28

You can't see it there, yeah? OK?

0:31:280:31:32

-But if I now put this under my hands, you can see...

-ALL: Ohhh!

0:31:320:31:36

..it's everywhere, OK?

0:31:370:31:41

Now, hold your hands up, Iona. Clean? In the ultraviolet. Other side.

0:31:410:31:44

Completely clean.

0:31:440:31:46

Now, if I shake your hand...

0:31:460:31:48

Hello, nice to see you! And now you put your hand under the there.

0:31:480:31:52

ALL LAUGH

0:31:520:31:53

Whoa! Now, if you shake hands with Ruaridh...

0:31:530:31:56

Hello! Shake hands. And underneath there - let's see.

0:31:590:32:02

Ew! Yes, it's spread, from me to you to you, right?

0:32:020:32:09

Very, very easy.

0:32:090:32:12

Now, imagine this was bacteria. OK?

0:32:120:32:15

I'm going to squidge it in your hands, OK, and rub that all in.

0:32:150:32:20

'Some bacteria can cause disease and make us feel unwell.

0:32:200:32:24

'You might know them as germs.

0:32:240:32:26

'They can get onto my hands when we sneeze or cough into them, or when we use the toilet.

0:32:260:32:30

'That's why it's important to wash your hands properly.

0:32:300:32:34

'I'm testing how well Jamie and Rosie wash their hands.'

0:32:340:32:37

Now, let's just check under the ultraviolet light,

0:32:370:32:41

see how glowing your hands are.

0:32:410:32:43

Ooh, yes!

0:32:430:32:45

Come on, Jamie. Squidge round. Oh, yes! Oh, yeah.

0:32:450:32:50

Go wash your hands.

0:32:500:32:52

Let's see how well they do.

0:32:520:32:55

-Ah-ha! Right, are your hands washed?

-Yes.

-Let me inspect them.

0:32:570:33:01

Do the old test.

0:33:010:33:02

Oh, yes, now if I was a parent, I'd say, "That's very good.

0:33:020:33:06

"Very good. Very clean." But is it?

0:33:060:33:08

Rosie, stick your hands under the ultraviolet.

0:33:080:33:11

-Oh-hoo-hoo! Eugh!

-ALL: Eugh!

0:33:110:33:13

Not so good.

0:33:130:33:14

It's all on your fingernail. It's all over your thumb.

0:33:140:33:18

Oh, yes, not so clean, but not bad. OK?

0:33:180:33:21

Jamie, stick your hand in there, son.

0:33:210:33:23

Let's see what we've got on yours.

0:33:230:33:25

ALL: Eugh!

0:33:250:33:28

Oh, yeah. I think Rosie won that one. Yeah, definitely, yeah.

0:33:280:33:33

It's on all your fingernails,

0:33:330:33:35

over the front and back of your hand, in the creases of your thumbs and fingers.

0:33:350:33:39

Not good enough.

0:33:390:33:41

So you see how you think you've washed your hands carefully enough,

0:33:410:33:46

but actually to wash your hands really carefully and properly to remove bacteria

0:33:460:33:50

it's quite hard.

0:33:500:33:51

The correct way to wash your hands, of course, using soap and hot water

0:33:510:33:56

is to put the soap there, rub, rub, rub, right?

0:33:560:33:59

Both sides and then interlock your fingers like this

0:33:590:34:02

and then do the backs of your fingers like that,

0:34:020:34:06

then you do your thumbs, yes?

0:34:060:34:07

And then your thumbs like that, OK?

0:34:070:34:10

And then the back of your hands like that.

0:34:100:34:13

And then rinse it all off, OK?

0:34:130:34:15

So it's actually quite hard work.

0:34:150:34:18

Bacteria are the one thing

0:34:180:34:21

that we didn't have to put inside the box because they're already there.

0:34:210:34:25

They're everywhere -

0:34:250:34:27

tiny living things, or micro-organisms, that you can't see without a microscope.

0:34:270:34:34

In the Rot Box, we have an incredible microscope

0:34:340:34:38

that magnifies the bacteria a breathtaking 7,000 times.

0:34:380:34:42

This allows us to have a much more detailed look.

0:34:420:34:46

With enough food and water,

0:34:460:34:49

the numbers of bacteria can increase alarmingly fast.

0:34:490:34:53

They increase by dividing into two every 30 minutes,

0:34:530:34:57

so after just 24 hours,

0:34:570:35:00

one bacterium becomes just over 281 billion bacteria.

0:35:000:35:07

They make up the largest number of living organisms on the planet.

0:35:070:35:13

There are trillions and trillions and trillions of micro-organisms around the earth.

0:35:130:35:19

But they're not all harmful, some of them help us.

0:35:190:35:23

Importantly, bacteria live in our gut, helping us to digest our food.

0:35:230:35:29

Now there are bacteria all over us obviously,

0:35:320:35:35

but there's also lots of bacteria inside us.

0:35:350:35:37

-Where do you think you could find lots of bacteria?

-In your stomach.

-Yeah, lots of bacteria.

0:35:370:35:44

-Up your nose.

-Yes, lots of bacteria there.

0:35:440:35:46

-In your ears.

-In your ears. Yes. Anywhere else?

0:35:460:35:50

-In your mouth.

-Particularly in your mouth,

0:35:500:35:52

so lots of bacteria in there, some are good, some are bad.

0:35:520:35:56

What I want to show you is how important it is to brush your teeth.

0:35:560:36:01

I'm sending Iona and Mram off to brush their teeth so I can demonstrate

0:36:010:36:05

how important it is to do it properly.

0:36:050:36:09

-Have you brushed them properly?

-Yes.

-Yes.

0:36:120:36:14

Well, I've got here little special tablets called disclosing tablets

0:36:140:36:18

and you can have one each, right?

0:36:180:36:21

It will show if you've really brushed your teeth properly,

0:36:210:36:26

so what I want you do to is...

0:36:260:36:28

in your mouth, roll it around your tongue

0:36:280:36:30

and get all the liquid over your teeth and gums,

0:36:300:36:33

do not swallow it,

0:36:330:36:34

and then, once you've done that, go to the kitchen

0:36:340:36:36

and spit it out and rinse your mouth out with fresh water

0:36:360:36:40

and then come back.

0:36:400:36:41

CHILDREN GIGGLE

0:36:420:36:43

Now what this does is,

0:36:450:36:46

the red dye sticks to the plaque.

0:36:460:36:49

'Plaque is a sticky film containing bacteria

0:36:490:36:52

'that can build up on your teeth.

0:36:520:36:54

'The bacteria love to feed on sugar and when they feed,

0:36:540:36:57

'they make acid which can rot your teeth.'

0:36:570:37:00

It's very important to brush all that plaque off,

0:37:000:37:03

that plaque bacteria off,

0:37:030:37:05

and the red tablets show where the plaque is.

0:37:050:37:08

Now you've brushed your teeth properly. Let's just see.

0:37:080:37:12

You've got a little bit of plaque just on the bottom of that one.

0:37:120:37:16

Yes, that's not too bad at all.

0:37:170:37:21

Let me see.

0:37:210:37:22

Open up.

0:37:230:37:25

Now there's some plaque on the edge of that tooth there,

0:37:250:37:28

some plaque along the edge of that side.

0:37:280:37:30

Now the ones who haven't brushed their teeth, right? Oh!

0:37:320:37:35

Oh-h!

0:37:350:37:37

Let's see yours.

0:37:370:37:39

Go, "Nnnnyah!"

0:37:390:37:40

Yeah. Ruaridh, open up. Oh!

0:37:420:37:47

I think you just had it on your tongue.

0:37:470:37:49

You didn't roll it around your teeth.

0:37:490:37:51

OK, that's quite clear to me that the two who've brushed their teeth

0:37:510:37:57

have done quite a good job and you've removed most of the plaque.

0:37:570:38:01

I'm impressed with you two.

0:38:010:38:03

Bacteria are micro-organisms, tiny single-celled creatures

0:38:080:38:12

that can't be seen without a microscope.

0:38:120:38:15

They're absolutely everywhere

0:38:170:38:19

and can multiply in numbers incredibly quickly.

0:38:190:38:22

As a result, there are trillions and trillions and trillions of them on earth.

0:38:220:38:28

Not all bacteria are harmful, some can be helpful too.

0:38:280:38:33

They're very easily spread,

0:38:330:38:35

so it's important to wash hands and brush teeth thoroughly.

0:38:350:38:38

This will help to stop the spread of harmful bacteria

0:38:380:38:42

or germs.

0:38:420:38:44

Inside this large glass box,

0:38:550:38:58

something extraordinary is happening.

0:38:580:39:01

Food is being left to rot for eight weeks in our own unique laboratory.

0:39:010:39:08

This is an investigation

0:39:110:39:12

into nature's biggest and best recycler - decay.

0:39:120:39:18

And it's being done on a scale that has never been tried before.

0:39:180:39:23

I'm Dr George McGavin.

0:39:230:39:26

I'm a biologist with a particular passion for insects.

0:39:260:39:30

The Rot Box detectives, Iona, Rosie,

0:39:300:39:34

Ruaridh, Mram and Jamie

0:39:340:39:38

are going to help me investigate the amazing world of rot and decay.

0:39:380:39:43

'There's mould...'

0:39:470:39:49

The mould has just covered that entire box.

0:39:490:39:53

'..bacteria...'

0:39:530:39:54

-Where you can see those glowing bits...

-Yeah.

0:39:540:39:57

..that's bacteria.

0:39:570:39:59

'..and flies.'

0:39:590:40:00

It's pretty unpleasant, I've got to say.

0:40:010:40:03

'It has taken eight months to build this giant Rot Box

0:40:070:40:10

'and now conditions are perfect inside.

0:40:100:40:14

'It's warm, there's water, air and plenty of food -

0:40:150:40:18

'all the things decay loves to feast and grow on.

0:40:180:40:24

'In the real world, female flies find the stench of rot irresistible

0:40:240:40:28

'and will be attracted to it instantly,

0:40:280:40:31

'as they find it the ideal place to lay their eggs,

0:40:310:40:35

'but because our Rot Box is sealed, no smell is escaping,

0:40:350:40:39

'so we need to put the flies into the box.'

0:40:390:40:42

And there they go.

0:40:420:40:44

Well, that's it. We're up and running

0:40:440:40:46

and it's time to leave all this to the agents of decay.

0:40:460:40:50

Back at Rot Box Detective HQ,

0:40:550:40:57

we wanted to investigate flies in more detail.

0:40:570:41:01

An adult fly can live up to five days,

0:41:010:41:04

but in such a short life, this tiny creature is incredibly busy.

0:41:040:41:09

This is a fly actually laying an egg. Now look at that.

0:41:090:41:13

See? The female's got this long bit at the back of the abdomen

0:41:130:41:16

through which the eggs pass,

0:41:160:41:17

so she's actually laying eggs there on some meat.

0:41:170:41:21

ALL: Wow!

0:41:210:41:23

-Oh, that's a fly!

-Oh, right!

0:41:230:41:27

Now if we go to the maggot,

0:41:270:41:29

when those eggs hatch and the little fly larvae,

0:41:290:41:32

which are called maggots, hatch out,

0:41:320:41:34

they've got little sharp hooks at the head end

0:41:340:41:36

with which they tear the meat. Look at that.

0:41:360:41:39

-Look. See?

-That's horrible.

0:41:390:41:41

And they just rip through the meat.

0:41:410:41:44

Now the great thing about fly maggots is that they can breathe through special holes

0:41:440:41:48

at their rear end called spiracles,

0:41:480:41:51

so we breathe through our mouths, fly larvae haven't got that -

0:41:510:41:54

they breathe through a system of tubes,

0:41:540:41:57

so it can feed and breathe at the same time.

0:41:570:41:59

And the last film is a fly after it's fully-grown,

0:41:590:42:03

after the maggot's eaten all it can eat,

0:42:030:42:05

it then becomes a pupae and it stays in there

0:42:050:42:09

and it emerges as an adult fly and here is a film.

0:42:090:42:12

Look at this. Wow! here is a fly actually emerging,

0:42:120:42:16

and after it's pushed itself out, it dries one wing,

0:42:160:42:19

and then it dries the other wing

0:42:190:42:22

and then it flies off.

0:42:220:42:23

Cool!

0:42:230:42:25

Oh, look, now it's flying.

0:42:250:42:27

Fantastic.

0:42:270:42:29

There you go.

0:42:290:42:30

We're making flytraps

0:42:340:42:36

to see how many flies will smell our rotting fish,

0:42:360:42:38

so that we can have a closer look at them in action.

0:42:380:42:42

That's the trap made. What we have to do now to attract the flies is to put in the bait.

0:42:510:42:57

Now, do you want a head or a tail?

0:42:570:42:59

-A head.

-Head. All right. Hold that.

0:42:590:43:01

We should have one head left. Oh, there it is.

0:43:010:43:05

-ALL: Eugh!

-Eugh!

0:43:050:43:06

Lovely fishy bait. Smelly, smelly. And then you put that in.

0:43:060:43:09

Stick it in there. So there we are.

0:43:090:43:12

Now, how do you think the trap works?

0:43:120:43:16

The fly goes in that hole and then it gets stuck and then it can't fly out.

0:43:160:43:20

-Yeah, it's like a creel or a lobster pot.

-Can't it go out there?

0:43:200:43:25

Some flies could fly out again, but flies are not terribly bright,

0:43:250:43:29

and after they're in there, they tend to fly up,

0:43:290:43:32

so they don't find the hole very easily,

0:43:320:43:36

so although some of them will escape, not many of them escape.

0:43:360:43:39

And there is your completed flytrap.

0:43:390:43:42

-Awesome.

-Now where would be the best place to hang them up?

0:43:420:43:46

A bright place, somewhere really warm, so it attracts more flies

0:43:460:43:50

-and the fish gets more rotten.

-Absolutely.

0:43:500:43:53

I'll bet you anything, within 30 seconds, there'll be flies in there.

0:43:530:43:57

Oh, look, there's a fly in it already.

0:43:570:43:59

Oh, see how efficient it is.

0:43:590:44:01

Right, let's go.

0:44:010:44:04

Now why do you think the adult flies are attracted to the dead fish?

0:44:070:44:11

Because they want to leave an egg there?

0:44:110:44:16

Absolutely. That's where they lay their eggs.

0:44:160:44:18

Now adult flies don't live very long -

0:44:180:44:20

they only live about five or six days,

0:44:200:44:23

so when they're adult,

0:44:230:44:24

the only job they have is to mate and to lay their eggs.

0:44:240:44:27

I'm going to hang my trap up on this bolt over here,

0:44:270:44:31

-and then we'll hang yours up on those trees, OK?

-Mm-hm.

0:44:310:44:34

'A few hours later,

0:44:450:44:47

'and we're back at the traps to see if they're a success.'

0:44:470:44:50

Right, let's see who's caught the most flies.

0:44:500:44:53

-Whose trap is this one?

-Me and Rosie.

0:44:530:44:55

Right, well, you've got four flies on the inside,

0:44:550:44:59

quite a few on the outside and you've got lots of eggs on the head,

0:44:590:45:03

so that's really good.

0:45:030:45:04

Look, we nearly got one!

0:45:040:45:06

Let me see. Oh, you have got small ones on the outside.

0:45:060:45:09

You've got one fly at the back there

0:45:090:45:12

and no eggs.

0:45:120:45:14

Mmm?

0:45:140:45:16

And now, my trap...

0:45:170:45:19

..ooh, look at that.

0:45:200:45:22

-ALL: Oh-h!

-There's at least one, two, three, four, five, six, seven flies in there -

0:45:220:45:26

three species and lots of eggs. Look at that.

0:45:260:45:29

You can see all the eggs over the mouth

0:45:290:45:32

and in the mouth and on the head end, see? It could all change,

0:45:320:45:36

-because there might be more flies in your traps tomorrow.

-Yeah.

0:45:360:45:39

After five weeks, the Rot Box has begun to look like a giant flytrap.

0:45:430:45:49

There are now up to 10,000 flies trapped inside.

0:45:490:45:52

Outside in the real world, these flies would have escaped

0:45:550:45:59

out of a open window, but because the box is sealed,

0:45:590:46:02

they've got nowhere to go and food is running out fast.

0:46:020:46:07

I'm worried this huge number of flies will upset the balance of life in the box,

0:46:080:46:13

so I've decided to go in and take control.

0:46:130:46:17

Well, there are just now simply too many flies in here.

0:46:230:46:27

It's becoming quite unpleasant,

0:46:270:46:29

and it's causing a problem,

0:46:290:46:30

because of the flyspeck, that's their excrement,

0:46:300:46:33

which they leave on the surfaces inside the glass everywhere,

0:46:330:46:36

so it's time I tried to reduce them a little bit...

0:46:360:46:40

..manually.

0:46:410:46:43

The trouble is, they're flying quite low

0:46:430:46:47

and they're sitting on surfaces - it's actually very hard to get them.

0:46:470:46:51

It's no wonder flies are so hard to capture.

0:46:570:46:59

Their compound eyes give them all-round vision,

0:46:590:47:02

so they can respond to movement in a fraction of a second.

0:47:020:47:07

I'm never going to win this fly hunt.

0:47:090:47:11

'The team and I are taking the fly hunt outside.'

0:47:160:47:19

Right, well, we've been quite lucky with the rain.

0:47:190:47:22

Yep.

0:47:220:47:23

Oh, look at this. Look what I've found.

0:47:240:47:27

Look.

0:47:270:47:28

-Oh, wow!

-Look at that.

-Aw-w!

0:47:300:47:34

Who knows what that is?

0:47:340:47:36

-A pheasant.

-Yeah, it's a female pheasant

0:47:360:47:38

and I think it's probably been hit by a car, actually.

0:47:380:47:40

In the real world, everything dies at some point,

0:47:400:47:44

and when they do, bacteria start to act on them, breaking it down.

0:47:440:47:49

They produce smells, bad odours which attract organisms,

0:47:490:47:52

and if you remember back to your flytraps,

0:47:520:47:55

the flies were attracted to the decaying fish pretty quickly,

0:47:550:47:58

and the same thing will happen here.

0:47:580:48:00

Now what would happen if we didn't have flies laying their eggs in it,

0:48:000:48:04

and maggots eating it and other animals taking it away?

0:48:040:48:07

-What would happen?

-There'd be, like, loads of dead animals everywhere

0:48:070:48:10

-and it would smell.

-Exactly.

0:48:100:48:12

Flies and other things that recycle dead animals

0:48:120:48:16

really perform a fantastic job for us.

0:48:160:48:19

Flies, particularly, are one of the most important recycling animals.

0:48:190:48:23

Right, let's go.

0:48:230:48:24

Back at the Rot Box, the cycle of life continues.

0:48:320:48:35

Female flies are attracted to the rotting food,

0:48:360:48:39

laying up to 300 eggs at a time.

0:48:390:48:42

The eggs hatch into larvae called maggots.

0:48:430:48:46

Maggots are amazing feeders. They use sharp hooks to eat

0:48:460:48:50

and breathe through air holes called spiracles in their rear end.

0:48:500:48:55

The maggots then become pupae

0:48:550:48:57

from which young flies emerge and the whole cycle will begin again.

0:48:570:49:02

So even though flies spread bacteria and mould

0:49:020:49:05

by landing on fresh food,

0:49:050:49:06

they have a very important job as recyclers.

0:49:060:49:10

Inside this large glass box

0:49:170:49:20

something extraordinary is happening.

0:49:200:49:23

Food is being left to rot for eight weeks in our own unique laboratory.

0:49:230:49:30

This is an investigation into nature's biggest and best recycler...

0:49:330:49:38

..decay,

0:49:390:49:40

and it's being done on a scale

0:49:400:49:42

that has never been tried before.

0:49:420:49:47

I'm Dr George McGavin.

0:49:470:49:48

I'm a biologist with a particular passion for insects.

0:49:480:49:52

The Rot Box detectives, Iona, Rosie,

0:49:520:49:56

Ruaridh, Mram and Jamie

0:49:560:50:00

are going to help me investigate the amazing world of rot and decay.

0:50:000:50:06

'There's mound...'

0:50:080:50:10

The melon's just incredible. It's really been hammered. Look at that.

0:50:100:50:14

'..flies...'

0:50:140:50:15

The number of flies has absolutely skyrocketed.

0:50:150:50:19

'..and bacteria.'

0:50:190:50:20

As well as food, there's a compost heap in the Rot Box,

0:50:280:50:31

which includes vegetable waste and leaves.

0:50:310:50:34

This is a great place to see decomposition in action.

0:50:360:50:41

We've been adding green material to the top,

0:50:410:50:44

but if we clear the top layers down, what's been happening in here

0:50:440:50:47

is lots and lots of woodlice, worms beetles have been working away

0:50:470:50:52

at the green material, breaking it down,

0:50:520:50:55

decomposing it into smaller material,

0:50:550:50:57

smaller particles,

0:50:570:50:59

and that is then available for use

0:50:590:51:01

by the billions of bacteria and fungi which are also in here.

0:51:010:51:05

We'll be back to have a much more detailed look at these later on.

0:51:050:51:10

Back at Rot Box Detective HQ,

0:51:150:51:17

we are collecting leaves for our compost bin.

0:51:170:51:20

It's the best place to see natural recycling at work.

0:51:200:51:25

Right, let's come over to the compost bin.

0:51:290:51:34

Let me take that.

0:51:340:51:35

-Now do any of you do recycling?

-Yeah, I do.

0:51:350:51:40

Glass, paper and cardboard.

0:51:400:51:42

-OK.

-We recycle the garbage in our garden.

-Right.

0:51:420:51:45

-Oh, you do? So you've got a brown bin, have you?

-Yeah.

0:51:450:51:50

I've got a brown bin so I put, like, hedge cuttings and grass cuttings in it.

0:51:500:51:55

-So all the waste from the garden ends up in here?

-Yeah.

-Yeah.

0:51:550:51:58

That's what we're going to with the leaves we've raked up,

0:51:580:52:01

but before we empty it in, put your hand in there, tell me what you feel.

0:52:010:52:06

-Leaves.

-Nothing.

-Oh, it's warm.

0:52:060:52:08

It's warm!

0:52:080:52:09

-Oh, yeah.

-Wow!

0:52:090:52:11

Well, that's the bacteria breaking the stuff down.

0:52:110:52:14

-Right, empty the leaves in.

-Will there be enough room?

-Oh, yeah.

0:52:140:52:18

-Oh, yeah.

-There we are.

-Sorry.

-Right.

0:52:180:52:23

Who knows where this goes?

0:52:230:52:24

Once you've filled up your brown bin, where does it go?

0:52:240:52:28

-Bin lorry.

-Ah, well, I'm going to show you.

0:52:280:52:31

The leaves that we collected in the garden, we raked them up into the brown bin.

0:52:470:52:52

The brown bin gets picked up by the truck,

0:52:520:52:54

and the trucks all come here and there's one arriving now.

0:52:540:52:58

They open the back, all the green material gets pushed out,

0:52:580:53:01

and then a scoop comes and takes it to a shredder.

0:53:010:53:05

That's where the whole process begins.

0:53:050:53:07

It falls through these two huge rotating bars.

0:53:070:53:12

It grinds it all up

0:53:120:53:14

and it spits it out the bottom onto a bed

0:53:140:53:16

and then it gets carried out there into a pile

0:53:160:53:19

and the reason they do that is to break up

0:53:190:53:21

all that material into smaller bits,

0:53:210:53:24

so that it has a larger surface area,

0:53:240:53:27

so the bacteria can get to work on it.

0:53:270:53:28

Right, now, this... is where it all comes.

0:53:410:53:44

So, once it's been through the shredder,

0:53:440:53:47

it gets piled up in these long rows.

0:53:470:53:49

Now, the reason they don't pile it in one great pile

0:53:490:53:52

is if they had it in one huge pile, it would go all slimy,

0:53:520:53:56

there'd be no oxygen in the middle.

0:53:560:53:57

It would go all horrible.

0:53:570:53:59

So they have it in these rows so they get lots of air in there

0:53:590:54:02

and the air helps the bacteria and the decomposition.

0:54:020:54:04

And what happens next is they put this through a screen or a sieve,

0:54:040:54:09

it's like a giant sieve, and they take out all the big bits.

0:54:090:54:13

So all you're left with is fine compost.

0:54:130:54:16

-How hot do you think it is in there?

-20 degrees?

-No.

0:54:160:54:19

-40?

-No. Hotter than that.

0:54:190:54:22

-50 degrees?

-Hotter than that.

0:54:220:54:24

-85 degrees.

-That's a pretty good estimate. Let's see how hot it is.

0:54:240:54:29

'I'm using a thermal probe to measure the heat inside the pile.'

0:54:290:54:33

Let's see exactly how hot it is.

0:54:340:54:36

47, 49...50...

0:54:420:54:45

Going up!

0:54:460:54:48

-Will it make 60?

-Yes, it will.

0:54:490:54:51

-It will, it will!

-59.9...

0:54:510:54:55

60!

0:54:550:54:56

60 and rising. Now, the reason it gets really hot in here

0:54:560:54:59

is because there's billions of bacteria in here,

0:54:590:55:02

breaking all the material down

0:55:020:55:04

and as they break it down, they produce large amounts of heat.

0:55:040:55:08

What's the highest?

0:55:080:55:09

Some of these piles have even had fires in them

0:55:090:55:13

cos it's just so hot. That's the power of bacteria.

0:55:130:55:15

Now, once they've taken out all the big bits,

0:55:190:55:21

all the big bits of wood and roots and stuff,

0:55:210:55:23

the end result of all that recycling

0:55:230:55:25

is this beautiful, beautiful compost.

0:55:250:55:28

And that goes straight on your garden.

0:55:280:55:30

Now, we've speeded it up by having it broken down into smaller bits,

0:55:300:55:34

but recycling is happening all the time, all around us.

0:55:340:55:38

Back in the giant Rot Box, we can take a much closer look

0:55:420:55:45

at how recycling is happening in the compost heap.

0:55:450:55:48

As all gardeners know, compost turns dead plants

0:55:540:55:57

into a form of nutrient that new plants can use.

0:55:570:56:01

On the surface, animals like snails, slugs

0:56:040:56:06

and worms begin the process by eating the remains of plants,

0:56:060:56:10

helping to break them into smaller pieces.

0:56:100:56:13

Other small animals, like these mites,

0:56:160:56:18

feed on the waste products these creatures leave behind.

0:56:180:56:22

This process continues down through the compost,

0:56:240:56:27

with ever-smaller organisms reducing the plant waste

0:56:270:56:30

to ever-smaller pieces, until tiny micro-fauna

0:56:300:56:35

and bacteria are able to break down the very cells of the plants.

0:56:350:56:39

A teaspoon of soil contains four billion micro-organisms.

0:56:410:56:46

They finally release the goodness back into the soil

0:56:460:56:49

so that new organic life can grow.

0:56:490:56:51

Composting is happening all around us in the natural world.

0:56:570:57:02

I'm taking the Rot Box Detectives out to see if we can find some.

0:57:020:57:06

Now, over here...is what I like to see. A bit of decaying wood.

0:57:060:57:12

Now, look at this, this is fantastic.

0:57:130:57:16

Now, this is a brilliant habitat for all kinds of stuff.

0:57:160:57:20

This was once a piece of a tree.

0:57:200:57:22

Obviously, it's fallen off

0:57:220:57:24

and the whole of the wood is being eaten away,

0:57:240:57:27

transformed into just...

0:57:270:57:29

Look at that. It's all breaking down.

0:57:290:57:31

The thing I love about decaying wood is it has a wonderful smell.

0:57:330:57:37

Absolutely gorgeous.

0:57:410:57:43

The whole of the wood is being eaten away,

0:57:450:57:48

transformed into just... Look at that.

0:57:480:57:50

It's exactly the same process that we saw earlier.

0:57:500:57:53

It's recycling on a grand scale.

0:57:530:57:55

Composting is nature's wonderful way of recycling.

0:58:010:58:05

Plant and vegetable matter are gradually broken down.

0:58:050:58:09

First, by larger organisms like snails, slugs, worms

0:58:100:58:13

and woodlice, then by ever-smaller micro-organisms and bacteria.

0:58:130:58:19

This process can be speeded up by breaking down the organic matter

0:58:200:58:24

into small pieces, using machines.

0:58:240:58:28

The end result is beautiful compost,

0:58:280:58:30

full of goodness, ready to feed more plants

0:58:300:58:34

so that the whole process of life and growth can begin again.

0:58:340:58:38

Subtitles by Red Bee Media Ltd

0:58:580:59:01

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0:59:010:59:04

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