Catch up TV
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!
Source: CBBC
Most recent episodes of Hey You What If?
Hey You What If?
Series 1: 10. The Earth Was Flat?
Find out why a flat earth would feel very unflat indeed!
06-02-2026
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.
05-02-2026
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Hey You What If?
Series 1: 8. The Earth Stopped Spinning?
Find out why stopping the earth from spinning isn’t such a good idea.
04-02-2026
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Hey You What If?
Series 1: 7. Clouds Were Made Out Of Cotton Wool?
Clouds might look like cotton wool, but if they really were, things would get very messy.
03-02-2026
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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.
02-02-2026
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Hey You What If?
Series 1: 5. You Could Go On Holiday To Mars?
Experience the ultimate in long-distance travel - a holiday on Mars!
30-01-2026
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.
29-01-2026
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Hey You What If?
Series 1: 3. You Could Take A Lift To Space?
What would happen if there really was a lift that took you all the way up to space?
28-01-2026
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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?
27-01-2026
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.
26-01-2026
CBBC
Most popular episodes of Hey You What If?
Hey You What If?
Series 1: 5. You Could Go On Holiday To Mars?
Experience the ultimate in long-distance travel - a holiday on Mars!
30-01-2026
CBBC
Hey You What If?
Series 1: 3. You Could Take A Lift To Space?
What would happen if there really was a lift that took you all the way up to space?
28-01-2026
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 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 1: 1. You Fell Into A Black Hole?
Experience the most extraordinary ride in the universe – falling into a black hole.
26-01-2026
CBBC
Hey You What If?
Series 2: 24. You Surfed Without Water
If the beach is too far to go but you still want to spend some time surfing waves, then why not surf on land instead? Well, there are some very good reasons people don’t s ...
19-06-2025
CBBC
Hey You What If?
Series 1: 8. The Earth Stopped Spinning?
Find out why stopping the earth from spinning isn’t such a good idea.
04-02-2026
CBBC
Hey You What If?
Series 1: 7. Clouds Were Made Out Of Cotton Wool?
Clouds might look like cotton wool, but if they really were, things would get very messy.
03-02-2026
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 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