Catch up TV
Series 2: 14. You Built a Giant Sandcastle
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!
Source: CBBC
Most recent episodes of Hey You What If?
Hey You What If?
Series 1: 20. You Try To Catch A Falling Star?
What happens if you try to catch a falling star? Spoiler alert - probably best not to try!
08-10-2024
CBBC
Hey You What If?
Series 2: 13. You Were The Last Person On Earth
What would the planet be like if all other humans disappeared, leaving you as the last person on earth?
06-10-2024
CBBC
Hey You What If?
Series 2: 18. There Were No Colours
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!
04-10-2024
CBBC
Hey You What If?
Series 2: 5. You Could Stop Global Warming
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.
04-10-2024
CBBC
Hey You What If?
Series 2: 4. You Needed Two Of You
From cloning to 3D printing, what if we could actually make copies of ourselves?
03-10-2024
CBBC
Hey You What If?
Series 2: 3. We Got Rid Of Bugs
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!
02-10-2024
CBBC
Hey You What If?
Series 2: 2. You Walked Through Walls
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.
01-10-2024
CBBC
Hey You What If?
Series 2: 1. You Built A Mega Slide
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!
30-09-2024
CBBC
Hey You What If?
Series 2: 12. You Walked On Ceilings
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..
29-09-2024
CBBC
Hey You What If?
Series 2: 17. You Flew Like A Superhero
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.
27-09-2024
CBBC
Most popular episodes of Hey You What If?
Hey You What If?
Series 2: 17. You Flew Like A Superhero
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.
27-09-2024
CBBC
Hey You What If?
Series 2: 3. We Got Rid Of Bugs
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!
02-10-2024
CBBC
Hey You What If?
Series 2: 12. You Walked On Ceilings
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..
29-09-2024
CBBC
Hey You What If?
Series 2: 5. You Could Stop Global Warming
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.
04-10-2024
CBBC
Hey You What If?
Series 1: 9. The Moon Was Made Of Cheese?
Things don’t quite go to plan when the moon turns into cheese.
21-12-2023
CBBC
Hey You What If?
Series 2: 13. You Were The Last Person On Earth
What would the planet be like if all other humans disappeared, leaving you as the last person on earth?
06-10-2024
CBBC
Hey You What If?
Series 1: 20. You Try To Catch A Falling Star?
What happens if you try to catch a falling star? Spoiler alert - probably best not to try!
08-10-2024
CBBC
Hey You What If?
Series 2: 15. You Shrunk The Earth
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.
02-09-2024
CBBC
Hey You What If?
Series 1: 6. You Could Levitate?
Good news - it’s possible to levitate! Bad news – there are some serious side effects.
18-12-2023
CBBC
Hey You What If?
Series 2: 19. You Only Ate Burgers
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 ...
10-09-2024
CBBC