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Series 2: 25. Earth Ran out of Energy
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.
Source: CBBC
Most recent episodes of Hey You What If?
Hey You What If?
Series 1: 16. You Could Actually Reach For The Stars?
Want to reach for the stars? It would be the journey of a lifetime - literally.
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Series 1: 15. Everything You Touched Turned To Gold?
What if you could turn things to gold? This episode shows that it might not work out that well.
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Series 1: 14. You Could Live On The Moon?
Some day people will live on the moon – find out just what they are in for.
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Series 1: 13. You Could Shrink Yourself?
If you have always wanted to shrink yourself, this is the episode for you!
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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!
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Series 1: 11. We Could Actually Stop Climate Change?
The planet is being destroyed - but this episode demonstrates the things you can do to help save it.
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Hey You What If?
Series 1: 10. The Earth Was Flat?
Find out why a flat earth would feel very unflat indeed!
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Series 1: 9. The Moon Was Made Of Cheese?
Things don’t quite go to plan when the moon turns into cheese.
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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.
19-05-2026
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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.
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Most popular episodes of Hey You What If?
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.
20-05-2026
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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?
13-03-2026
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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!
27-02-2026
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Hey You What If?
Series 2: 16. Money Grew On Trees
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.
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Hey You What If?
Series 2: 7. You Could Shout Round The World
Find out how to shout from one side of the world to the other.
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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.
16-03-2026
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Series 1: 15. Everything You Touched Turned To Gold?
What if you could turn things to gold? This episode shows that it might not work out that well.
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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.
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Series 1: 6. You Could Levitate?
Good news - it’s possible to levitate! Bad news – there are some serious side effects.
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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 ...
24-04-2026
CBBC