Hey You! What If...

Experience the most extraordinary ride in the universe – falling into a black hole.

The deepest hole humankind ever dug only got one thousandth of the way through the earth. But what would happen if you kept digging?

What would happen if there really was a lift that took you all the way up to space?

Find out why turning into a huge giant would be no fairy tale.

Experience the ultimate in long-distance travel - a holiday on Mars!

Good news - it’s possible to levitate! Bad news – there are some serious side effects.

Clouds might look like cotton wool, but if they were, things would get very messy.

Find out why stopping the Earth from spinning isn’t such a good idea.

Things don’t quite go to plan when the moon turns into cheese.

Find out why a flat Earth would feel very unflat indeed!

The planet is being destroyed - but this episode demonstrates the things you can do to help save it.

It really is possible to time travel into the future, and the team show you how!

If you have always wanted to shrink yourself, this is the episode for you!

Some day people will live on the moon – find out just what they are in for.

What if you could turn things to gold? This episode shows that it might not work out that well.

Want to reach for the stars? It would be the journey of a lifetime - literally.

Find out why living in slow motion would let you see things no-one else can!

Would it be possible to live on an Earth shaped like a doughnut? You might be surprised!

A fun run goes wrong when one ambitious runner tries running at the speed of sound.

What happens if you try to catch a falling star? Spoiler alert - probably best not to try!

Why waking up with lizard powers would make you useless on earth but a superhero in space!

It’s the ultimate baking challenge: making a gingerbread house you could actually live in.

Is it really possible to teleport? Spoiler alert: it could end in disaster!

Empty the oceans and you’d see hidden wonders, but you’d also cause the end of the world.

See what would happen if you really could switch off the sun.

Anyone can fly like a bird – you just have to travel across the solar system to do it!