07/03/2017 Newsround

Afternoon all, it's Ayshah here live with Tuesday's Newsround with loads

of great stuff to tell you...

We get a pigeon's-eye view of pollution....

And...

A flying visit from author David Walliams to answer your questions...

Gary Barlow has spoken out against reports that Five-to-Five -

the boy band who won TV show Let It Shine -

would just be the backing band in a musical about Take That.

Reports have said that the boys wouldn't be the main

stars of the show, but

the people behind the musical told Newsround, that the rumours

were "simply not true".

A special project helping to measure pollution has had help from some

feathered scientists.

Yes, pigeons are being used to find out more about air quality.

Martin has been coo-vering the story...

Pigeons!

We see them all the time in the city, trying to find bits

of food and scurrying about.

But how are they linked to pollution?

Apart from both beginning with the letter P?

Well, scientists are using pigeons to gather information

by strapping these small sensors to the backs of them.

Why?

It is known that pollution that comes out of cars with diesel

engines rises to rooftop levels.

But, what is not known, is what happens next to the pollution?

Where does it go?

Step in Pigeon Patrol!

I kind of thought, well...

Birds fly everywhere.

If they can carry our sensors, and if they can be accurate

enough and tiny enough, we can understand the dispersion

of air pollution around the city.

Birmingham University are carrying out a test flight.

I feel nervous.

This is the first time that we've done this.

One of the pigeons is fitted with a small lightweight sensor

and camera to record the flight.

I'm happy with that.

I just hope they go home!

Just six minutes later, the pigeons are back and the sensor

is still on its back.

The light is still flashing.

That's a good sign!

Rick and his team have been able to find out

the route the pigeons took, and the temperature of the air.

The information will help them figure out how pollution

moves around big cities.

What's this pigeon called?

I haven't got a name for him.

I call him number 80!

So thanks, pigeon number 80.

You've done everyone proud!

Thanks

Thanks Martin!

Whether it's Gangsta Grannies, awful aunties or demon dentists,

author David Walliams is not afraid to tackle difficult subjects,

whilst also making us giggle.

His latest story - Grandpa's Great Escape -

is about the adventures of a boy and his forgetful grandfather.

David came into the BBC earlier today, to answer some

of your burning questions...

Now, in something of a panic, the boy pulled the nearest handle.

And the ancient tank surged forward at a terrific speed.

Smash!

It demolished the wall of the museum with laughable ease!

What is your favourite book from when you were younger?

Charlie and the Chocolate Factory.

I used to go to a local library with my mum and dad

and sister every two

weeks, and that is the book that got me reading.

You mention that book and everybody knows it,

everybody has read it.

That's one of the greatest children's books of all time.

What made the teacher hate children so much?

The reason is that evil teachers are much more

interesting than nice teachers.

If you are writing a teacher character,

think about Miss Trunchbull who throws children

around by their pigtails and they fly out the window.

But yes, I thought it was much more fun to have a headteacher

who hates children.

What inspired you to become a really good writer?

I suppose I got into writing because I was doing comedy,

and I knew that comedians, when I was a kid I knew

that comedians generally wrote their own material,

and that got me into writing.

Then, I realised that writing really was for me the most

creative part of it all.

And I love that idea of a blank page and you create characters

and situations and scenes.

They leapt up onto the wing and climbed into the cockpit.

As with most World War II fighter planes, there was just one seat.

So, the boys sat on his grandfather's lap.

Cosy in here, isn't it, Squadron leader?

Remarked the old man.

For the first time in his life, Jack was sitting in a real Spitfire.

His dream was coming true.

Great

Great questions!

That's it from us.

Newsround's back at 07:40am tomorrow.

Don't forget to go online to find out why pandas are black and white -

I always wondered that!

See ya!