Hey You What If?
Hey You What If? is a comedy program on CBBC. We answer the ‘what if’ questions that you never even thought to ask! Each episode asks a question and takes you on an unforgettable journey where the impossible is made possible to find the answer! The program has been available since 2024. A total of 40 episodes have been broadcast, most recently in May 2025.
Last episode
Hey You What If?
We try out a crazy idea from science fiction to build a giant sphere around the sun and give us more energy than we'll ever need.
Catching up on Hey You What If??
Don't want to miss an episode anymore? Set up a free alarm and receive an email when new episodes are available. Handy!
Imagine if we had a thermostat that could turn the world temperature down - could we fix global warming? But be careful, a few degrees too far could cause an ice age.
From cloning to 3D printing, what if we could actually make copies of ourselves?
Bugs might be annoying, but we would soon regret it if we got rid of them - all our favourite foods would disappear, and there would be dung everywhere!
Wouldn't it be cool to be able to walk through walls? From turning into a gas to quantum trickery, we discover why it wouldn't be quite as useful as you'd like.
Could you build a slide to the other side of the world? You would need to start in space, use the slippiest slide ever and make sure you have enough supplies before you go down it!
There is a way that Earth could have a second Sun, so we try it out to see what happens.
We find out what would happen if you shrank the earth. You could jump higher and move faster, but you would end up with altitude sickness even at sea level.
We imagine a world where it's possible to move things with your mind like films, but find that the laws of physics mean that this superpower wouldn't quite work like you'd expect.
To throw a ball around the world, you need to start out in space, throw it ten times the speed of a bullet and make sure your ball does not explode when it hits the atmosphere.
Series 1
Things don’t quite go to plan when the moon turns into cheese.
Find out why stopping the Earth from spinning isn’t such a good idea.
Clouds might look like cotton wool, but if they really were, things would get very messy.
Good news - it’s possible to levitate! Bad news – there are some serious side effects.
Experience the ultimate in long-distance travel - a holiday on Mars!
It really is possible to time travel into the future, and the team show you how!
Find out why turning into a huge giant would be no fairy tale.
What would happen if there really was a lift that took you all the way up to space?
The deepest hole humankind ever dug only got one thousandth of the way through the earth. But what would happen if you kept digging?
Experience the most extraordinary ride in the universe – falling into a black hole.