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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..
Source: CBBC
Most recent episodes of Hey You What If?
Hey You What If?
Series 1: 12. You Can't Wait For Christmas?
It really is possible to time travel into the future, and the team show you how!
21-12-2025
CBBC
Hey You What If?
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!
27-11-2025
CBBC
Hey You What If?
Series 1: 2. You Could Dig Through The Earth?
The deepest hole humankind ever dug only got one thousandth of the way through the earth. But what would happen if you kept digging?
13-11-2025
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.
29-10-2025
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.
24-10-2025
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?
23-10-2025
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!
22-10-2025
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.
21-10-2025
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!
20-10-2025
CBBC
Hey You What If?
Series 1: 1. You Fell Into A Black Hole?
Experience the most extraordinary ride in the universe – falling into a black hole.
11-07-2025
CBBC
Most popular episodes of Hey You What If?
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?
21-05-2025
CBBC
Hey You What If?
Series 2: 6. You Lived On Venus
Venus has acid rain, crushing pressure, and is hotter than an oven, so it might not sound like the ideal place to live. However, up in the clouds it's almost just like home.
12-05-2025
CBBC
Hey You What If?
Series 1: 2. You Could Dig Through The Earth?
The deepest hole humankind ever dug only got one thousandth of the way through the earth. But what would happen if you kept digging?
13-11-2025
CBBC
Hey You What If?
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!
27-11-2025
CBBC
Hey You What If?
Series 2: 22. You Had Kangaroo Legs
Running a marathon is hard. At least it is for a human. But what if we could swap our legs with an animal – would that make it any easier? \n\nFirst, we try ...
17-06-2025
CBBC
Hey You What If?
Series 1: 18. The Earth Was Shaped Like A Doughnut?
Would it be possible to live on an Earth shaped like a doughnut? You might be surprised!
02-11-2023
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.
21-10-2025
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!
11-06-2025
CBBC
Hey You What If?
Series 1: 4. You Could Turn Into A Giant?
Find out why turning into a huge giant would be no fairy tale.
20-12-2024
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.
23-05-2025
CBBC