0:00:05 > 0:00:08# If you've got a question And you don't know where to go
0:00:08 > 0:00:11# Ask Nina for some help Cos she's got a science show
0:00:11 > 0:00:14# She makes sense of her senses While helping all her fans
0:00:14 > 0:00:17# By doing her experiments With potions and with bangs
0:00:17 > 0:00:19- # Touch your tongue - Tongue
0:00:19 > 0:00:21- # Fingers - Fingers
0:00:21 > 0:00:22- # Eyes- Eyes - Ears- Ears
0:00:22 > 0:00:24- # Nose- Nose
0:00:24 > 0:00:27# Nina and the Neurons Find out what you need to know
0:00:27 > 0:00:30# Nina and the Neurons Find out what you need to know
0:00:30 > 0:00:32# Luke he helps us with our eyes And Felix with our touch
0:00:32 > 0:00:35# Ollie sniffs out smells and scents And Belle she hears so much
0:00:35 > 0:00:38# Bud is Ollie's brother He helps us with our taste
0:00:38 > 0:00:41# They're Nina's little Neurons And they're coming to your place
0:00:41 > 0:00:43- # Touch your tongue - Tongue
0:00:43 > 0:00:45- # Fingers- Fingers
0:00:45 > 0:00:46- # Eyes- Eyes - Ears- Ears
0:00:46 > 0:00:48- # Nose- Nose
0:00:48 > 0:00:51- # Nina and the Neurons find out What you need to know,- Yeah!
0:00:51 > 0:00:54# Nina and the Neurons Find out what you need to know
0:00:54 > 0:00:56# Oh, yeah! #
0:00:56 > 0:00:59Toot-toot! Hello, lovely townspeople, hello.
0:00:59 > 0:01:01Oh, hello!
0:01:01 > 0:01:04I'm just playing with my little toy town and, oh,
0:01:04 > 0:01:08I've just noticed the roofs aren't on these houses.
0:01:08 > 0:01:10We don't want the rain getting in.
0:01:10 > 0:01:12BEEPING
0:01:12 > 0:01:16I hear a beep, I see a flash, I wonder what they're going to ask.
0:01:21 > 0:01:23BOTH: Hi, Nina!
0:01:23 > 0:01:24Hi!
0:01:24 > 0:01:26We've got a question for you.
0:01:26 > 0:01:29Why do houses have pointy roofs?
0:01:29 > 0:01:31That's a great question!
0:01:31 > 0:01:33Why do houses have pointy roofs?
0:01:33 > 0:01:36Well, lots of people live in houses with pointy roofs
0:01:36 > 0:01:37but why are they pointy?
0:01:37 > 0:01:41Why don't you come down to my workshop and we'll investigate?
0:01:41 > 0:01:46- BOTH: See you soon, Nina! Bye! - Bye.
0:01:46 > 0:01:49Well, I'm going to need some help to answer this one
0:01:49 > 0:01:51and I know just who to ask.
0:01:51 > 0:01:53OK, Neurons, time to get to work.
0:02:09 > 0:02:11ALL: Neurons at the ready, Nina.
0:02:11 > 0:02:15OK, today's question is why do houses have pointy roofs?
0:02:15 > 0:02:17Now, which Neuron do you think will be
0:02:17 > 0:02:20most useful in helping us find the answer?
0:02:20 > 0:02:22It's Belle!
0:02:22 > 0:02:24CHEERING
0:02:24 > 0:02:27ALL: Go, Belle! Go, Belle! Go, Belle!
0:02:27 > 0:02:30Go, Belle! Go, Belle! Go, Belle!
0:02:30 > 0:02:33Brilliant! I'm all ears, Nina.
0:02:33 > 0:02:36Today's question is why do houses have pointy roofs?
0:02:36 > 0:02:38And because we hear the sound of rain
0:02:38 > 0:02:42when it lands on a roof, Belle will be helping us today.
0:02:42 > 0:02:45Stand by, Neurons, I've a feeling I may need help from all of you.
0:02:45 > 0:02:50I need to get the workshop ready before the experimenters arrive.
0:02:50 > 0:02:53Lucas loves tenpin bowling.
0:02:53 > 0:02:55Harriet likes horse riding.
0:02:55 > 0:02:59But they both want to know, why do houses have pointy roofs?
0:03:01 > 0:03:02So today, for one day only,
0:03:02 > 0:03:06Lucas and Harriet become the experimenters.
0:03:14 > 0:03:16- Hi, guys!- BOTH: Hi, Nina!
0:03:16 > 0:03:20Welcome to my workshop and thank you for your great question,
0:03:20 > 0:03:23- why do houses have pointy roofs? - Yeah.
0:03:23 > 0:03:27Lots of buildings have pointy roofs, just like in my little toy town.
0:03:27 > 0:03:31But to find out why, let's start with an experiment.
0:03:31 > 0:03:36ALL: Whoop-whoop! An experiment! We're ready, Nina!
0:03:36 > 0:03:40I have made two dens, each with different roofs.
0:03:40 > 0:03:43- So what shape is your roof, Harriet?- Flat.- Mm-hm.
0:03:43 > 0:03:47- And what about you, Lucas, what shape is your roof?- Pointy.
0:03:47 > 0:03:48It is pointy!
0:03:48 > 0:03:51Now, we're going to find out what happens
0:03:51 > 0:03:54when it rains onto your different roofs.
0:03:54 > 0:03:56It's going to rain onto the flat roof first.
0:03:56 > 0:03:59Here we go, Harriet.
0:03:59 > 0:04:01SHE GASPS
0:04:01 > 0:04:04Oh, no!
0:04:05 > 0:04:07LAUGHTER
0:04:07 > 0:04:11- Oh, no! What's happening to the water?- It's staying on the roof.
0:04:11 > 0:04:15Yes, because your roof is flat, the water is staying on top of it.
0:04:15 > 0:04:17Nina! The roof's beginning to sag.
0:04:17 > 0:04:21That's right, Felix, the roof is bending because the water's
0:04:21 > 0:04:22on top of it.
0:04:22 > 0:04:25Now, you see, water is actually very heavy.
0:04:25 > 0:04:28Two buckets of water weigh nearly as much
0:04:28 > 0:04:30as one of you experimenters.
0:04:30 > 0:04:33Wow! That is heavy!
0:04:33 > 0:04:36Because the rainwater stayed on top,
0:04:36 > 0:04:39it made a puddle and made the roof sag in the middle.
0:04:39 > 0:04:44Now, let's see what happens when it rains onto the pointy roof.
0:04:48 > 0:04:50LAUGHTER
0:04:52 > 0:04:56Oh, ha-ha-ha! So, what's happening to the water this time?
0:04:56 > 0:04:58It's sliding off.
0:04:58 > 0:05:00Yes, because this roof is pointy,
0:05:00 > 0:05:04the water runs down rather than collecting on top.
0:05:04 > 0:05:07And with no heavy water lying on top,
0:05:07 > 0:05:10the roof won't sag even if it rains all day.
0:05:10 > 0:05:14But, Nina, some buildings have got flat roofs.
0:05:14 > 0:05:18Ah-ha! Now, most buildings that look like they've got flat roofs,
0:05:18 > 0:05:21actually have a very slight slope.
0:05:21 > 0:05:25So the rain runs down the slope, into a pipe and then drains away.
0:05:25 > 0:05:29So buildings have pointy roofs to let rainwater run off.
0:05:29 > 0:05:34Because water is heavy, if it stayed on a roof, it would make it sag.
0:05:34 > 0:05:36That's right, Neurons.
0:05:36 > 0:05:40- How do they make the roofs pointy? - That's a great question.
0:05:40 > 0:05:43How do the builders make the pointy shape?
0:05:43 > 0:05:46Well, I think we need to go somewhere with lots
0:05:46 > 0:05:48of pointy roofs to find out.
0:05:54 > 0:05:57I wonder where Nina is taking us.
0:05:57 > 0:06:01She said we were going somewhere with lots of pointy roofs.
0:06:01 > 0:06:05- Tents have pointy roofs, maybe we're going camping.- Camping!
0:06:05 > 0:06:10We can have a campfire and sizzle sausages. Yippee!
0:06:10 > 0:06:12I don't see any tents, Neurons,
0:06:12 > 0:06:15but I do see a lot of pointy roofs.
0:06:16 > 0:06:20OK, so far we've found out that buildings have pointy roofs
0:06:20 > 0:06:22to let the rainwater run off them.
0:06:22 > 0:06:26But now we want to know how pointy roofs are made.
0:06:26 > 0:06:29So we've come here to this building site.
0:06:29 > 0:06:33Remember, never go onto a building site on your own.
0:06:33 > 0:06:35They can be very dangerous.
0:06:35 > 0:06:39That's right, Felix, we've got special permission to be here
0:06:39 > 0:06:43but you should never go into a building site without a grown-up.
0:06:43 > 0:06:45Now, experimenters have a look over there.
0:06:45 > 0:06:49- Can you see the pointy roofs that they're building?- Yes!
0:06:49 > 0:06:53Just look at all the beams in that big pointy roof.
0:06:53 > 0:06:57- It looks like a triangle. - Yes, it does look like a triangle.
0:06:57 > 0:07:01There are beams across the top and there's a beam across the bottom.
0:07:01 > 0:07:04This beam across the bottom is very important.
0:07:04 > 0:07:07Let's do an experiment to find out why.
0:07:07 > 0:07:10You've both got the walls of a house and I've got
0:07:10 > 0:07:14different-shaped roofs. One here has the beam underneath it.
0:07:14 > 0:07:15Lucas, that's for you.
0:07:15 > 0:07:18This one does not have a beam underneath it.
0:07:18 > 0:07:20Harriet, that's for you.
0:07:20 > 0:07:24Let's see what happens when you put your roofs onto your houses.
0:07:24 > 0:07:26Harriet, you go first.
0:07:29 > 0:07:32Very good. OK, now, Lucas, it's your turn.
0:07:32 > 0:07:34Harriet, you can help.
0:07:35 > 0:07:39OK, now, Harriet, what's happening to your walls?
0:07:39 > 0:07:41They're bending.
0:07:41 > 0:07:43Yes, the walls are bending.
0:07:43 > 0:07:45So when this roof rests on these walls,
0:07:45 > 0:07:50its weight pushes down and out, which makes the walls bend.
0:07:50 > 0:07:52Now, Lucas, what about yours?
0:07:52 > 0:07:55Have a look at your walls, what's happening?
0:07:55 > 0:07:57They stayed straight.
0:07:57 > 0:08:00Yes, the walls on your house are not bending and that's
0:08:00 > 0:08:04because when the roof with the beam rests on the walls,
0:08:04 > 0:08:07its weight does push down but the beam stops
0:08:07 > 0:08:11the roof from pushing out, so the walls stay straight.
0:08:11 > 0:08:13And real roofs work in the same way.
0:08:13 > 0:08:18They're built with beams across the bottom to make a triangle.
0:08:18 > 0:08:21The bottom beams stop the roof from pushing out,
0:08:21 > 0:08:23which helps the roof to keep its shape.
0:08:23 > 0:08:25- What are those? - Oh, great question!
0:08:25 > 0:08:28Those are roof tiles and builders put them
0:08:28 > 0:08:31on the roofs to stop water getting in.
0:08:31 > 0:08:37In fact, let's go back to the workshop to find out how they work.
0:08:37 > 0:08:40So your question was, why do houses have pointy roofs?
0:08:40 > 0:08:44So far we've discovered roofs are pointy to let the rain
0:08:44 > 0:08:48run off them and they have beams to help keep their shape.
0:08:48 > 0:08:51Builders cover the roofs in roof tiles.
0:08:51 > 0:08:54But now we want to find out how they work.
0:08:54 > 0:08:56So I've got some tiles here.
0:08:56 > 0:08:58Now, this is a slate tile.
0:08:59 > 0:09:03- So what does it look like?- Flat. - Yes, it is flat.
0:09:03 > 0:09:08And this tile is made of special concrete and what does it look like?
0:09:08 > 0:09:10- Wavy.- That's right.
0:09:10 > 0:09:14So tiles can all look different but they all have to be waterproof
0:09:14 > 0:09:16so that water can't get through them.
0:09:16 > 0:09:19Oh, I like the sound of that,
0:09:19 > 0:09:20waterproof.
0:09:20 > 0:09:24Let's do an experiment to find out how waterproof tiles fit
0:09:24 > 0:09:28together to make the whole roof waterproof.
0:09:28 > 0:09:30So we've got two pointy roofs here
0:09:30 > 0:09:32but they're not quite finished, are they?
0:09:32 > 0:09:34- BOTH: No!- Hee-hee-hee!
0:09:34 > 0:09:37No, I think we need to add some more tiles.
0:09:37 > 0:09:40This roof here has tiles that are next to each other,
0:09:40 > 0:09:42they're not overlapping at all.
0:09:42 > 0:09:46And your roof has tiles that are overlapping like this.
0:09:46 > 0:09:49A bit like fish scales.
0:09:49 > 0:09:52- So shall we finish tiling our roofs?- BOTH: Yes!
0:09:52 > 0:09:54Okey-doke, let's get building.
0:10:02 > 0:10:04Next one.
0:10:06 > 0:10:08- Last tile!- Thank you!
0:10:11 > 0:10:15Well done! These roofs look fantastic.
0:10:15 > 0:10:18Oh, no! But it's about to start raining!
0:10:18 > 0:10:21Oh-ho! There you go, Harriet.
0:10:21 > 0:10:23Go!
0:10:29 > 0:10:31That's it!
0:10:45 > 0:10:48Wow! That was a lot of rain.
0:10:48 > 0:10:51OK, so let's have a look and see if our roofs were waterproof.
0:10:51 > 0:10:55What about yours, Lucas? Let's have a look. Oh, dear.
0:10:55 > 0:10:58This roof didn't stop the water getting in and that's
0:10:58 > 0:11:01because the tiles are next to each other.
0:11:01 > 0:11:06They don't overlap so the water got in through the joins.
0:11:06 > 0:11:09Now, let's have a look at the roof with the overlapping tiles.
0:11:09 > 0:11:11Huh! It is much drier!
0:11:11 > 0:11:15The water couldn't get in through the joins because there's
0:11:15 > 0:11:19another tile underneath, so the water just drained off.
0:11:19 > 0:11:22Roof tiles need to overlap because if they don't,
0:11:22 > 0:11:25they'll let the water in. Eugh!
0:11:25 > 0:11:26That's right, Neurons.
0:11:26 > 0:11:29Roof tiles need to overlap to make
0:11:29 > 0:11:31sure the rain can't get through them.
0:11:31 > 0:11:36# Nina and the Neurons. #
0:11:36 > 0:11:39So your question was, why do houses have pointy roofs?
0:11:39 > 0:11:42And I think we've answered it.
0:11:42 > 0:11:46Lots of houses have pointy roofs so the rain runs off.
0:11:46 > 0:11:50Because water is heavy, if it stayed on a roof, it would make it sag.
0:11:50 > 0:11:55Builders put beams under the roof to hold it in a pointy shape.
0:11:55 > 0:11:59The beams stop the roof from pushing out and keep the walls straight!
0:11:59 > 0:12:03Builders cover the roofs with tiles that overlap
0:12:03 > 0:12:06so no splishy-splashy rain gets inside.
0:12:06 > 0:12:09So I hope that's answered your question.
0:12:09 > 0:12:12BOTH: Thanks, Nina. Bye!
0:12:12 > 0:12:15You are welcome. Bye!
0:12:17 > 0:12:21If you want to know more about the science around us go to the
0:12:21 > 0:12:23Nina section on the CBeebies website.
0:12:23 > 0:12:25Have fun!
0:12:25 > 0:12:28# Super structures Super structures
0:12:28 > 0:12:30# Super structures Super structures
0:12:30 > 0:12:32# Super structures
0:12:32 > 0:12:35# Some of them are tall Some of them are wide
0:12:35 > 0:12:38# They're bumpy, lumpy Wiggly too
0:12:38 > 0:12:40# Wiggly too
0:12:40 > 0:12:43# Some of them are strong Some of them are small
0:12:43 > 0:12:45# Like me!
0:12:45 > 0:12:47# They're windy, whirly Wooshy too
0:12:47 > 0:12:49# All around
0:12:49 > 0:12:51# Look over here
0:12:51 > 0:12:54# Build it, stack it Pile it up
0:12:54 > 0:12:57# Come on Let's get building
0:12:57 > 0:12:58# Building, building, building
0:12:58 > 0:13:02# Race it, hold it Make it stick
0:13:02 > 0:13:06# Come on Let's get building
0:13:06 > 0:13:09# Come on Let's get building
0:13:12 > 0:13:16# Some of them are cosy warm Some of them are chilly
0:13:16 > 0:13:19# Keep us safe and hide us too
0:13:19 > 0:13:20# Hide us too
0:13:20 > 0:13:24# Some of them are just for fun Or help us to stay dry
0:13:24 > 0:13:27# They're underground And high up too
0:13:27 > 0:13:30# Look around Over here
0:13:30 > 0:13:34# Build it, stack it Pile it up
0:13:34 > 0:13:37# Come on Let's get building
0:13:37 > 0:13:39- # Building,- building,- building
0:13:39 > 0:13:42# Race it, hold it Make it stick
0:13:42 > 0:13:46# Come on, let's get building
0:13:46 > 0:13:49# Come on, let's get building! #
0:13:51 > 0:13:54And remember, there are super structures everywhere.
0:13:54 > 0:13:58Whether they're big or small, wide or tall, we can all get building.
0:13:58 > 0:14:00See you again soon. Bye!
0:14:00 > 0:14:02# Nina and the Neurons. #
0:14:02 > 0:14:04ALL: Bye! Get building!