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 41 episodes have been broadcast, most recently in July 2025.
Last episode
Hey You What If?
Experience the most extraordinary ride in the universe – falling into a black hole.
Catching up on Hey You What If??
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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.
Sometimes you want to go surfing, but it's too far to the beach, so we try surfing on land with the help of a volcano and some giant fans.
We imagine becoming unbreakable by removing our bones, turning our skin to metal and finally by becoming completely elastic, but indestructibility isn't everything we hoped for.
To win a marathon, are you better off with the bouncing legs of a kangaroo, the long legs of a T rex or sticking with the legs of a human?
We reveal how to create the ultimate in tall buildings by going to the moon and taking inspiration from wedding cakes.
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.
If everyone in the world ate nothing but cheeseburgers, we would run out of land, and even if we went meat-free, we would have to invent some crazy burgers to get the nutrients we need.
Imagine removing all the colours one by one? It would change more than just how things look, and after taking out just three colours, we would not be able to see anything at all!
Flying like a superhero may sound like enormous fun, but there are some serious downsides that Hollywood does not tell you about - weather, extreme cold and even fizzy blood.
If you had a tree that could grow money, would that make you rich? Even if you wait 20 years for your tree to grow, you will probably end up no richer than you started.
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.
Is it possible to build a sand castle the size of a real castle? We imagine how it could be done, using a pneumatic drill and a huge, solid gold steamroller!
What would the planet be like if all other humans disappeared, leaving you as the last person on earth?
We try using a gravity-bending black hole and spinning the earth faster to see if we can make it possible to walk on the ceiling..
We look at whether some animals can get gigantic and find out that if you are being chased by a giant snail or a humungous butterfly, then fear not, you must be dreaming.
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.
There is a way that Earth could have a second Sun, so we try it out to see what happens.
We try out three potential ways to become invisible and discover some surprising side effects.
Find out how to shout from one side of the world to the other.