Catch up TV
Series 1: 5. You Could Go on Holiday to Mars?
Experience the ultimate in long-distance travel - a holiday on Mars!
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!
27-02-2026
CBBC
Hey You What If?
Series 1: 19. You Could Run At The Speed Of Sound?
A fun run goes wrong when one ambitious runner tries running at the speed of sound.
26-02-2026
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!
25-02-2026
CBBC
Hey You What If?
Series 1: 17. You Could Live In Slow Motion?
Find out why living in slow motion would let you see things no-one else can!
24-02-2026
CBBC
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.
23-02-2026
CBBC
Hey You What If?
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.
13-02-2026
CBBC
Hey You What If?
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.
12-02-2026
CBBC
Hey You What If?
Series 1: 13. You Could Shrink Yourself?
If you have always wanted to shrink yourself, this is the episode for you!
11-02-2026
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!
10-02-2026
CBBC
Hey You What If?
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.
09-02-2026
CBBC
Most popular episodes of Hey You What If?
Hey You What If?
Series 1: 13. You Could Shrink Yourself?
If you have always wanted to shrink yourself, this is the episode for you!
11-02-2026
CBBC
Hey You What If?
Series 2: 23. You Were Indestructible
On the face of it, humans are a bit breakable. We have these hard skeletons that can crack if you have a tumble. But if we were indestructible, like a superhero, then we&rsquo ...
18-06-2025
CBBC
Hey You What If?
Series 1: 19. You Could Run At The Speed Of Sound?
A fun run goes wrong when one ambitious runner tries running at the speed of sound.
26-02-2026
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 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: 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: 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: 23. You Could Teleport?
Is it really possible to teleport? Spoiler alert: it could end in disaster!
29-10-2024
CBBC
Hey You What If?
Series 2: 21. You Built The Tallest Building On Earth
So you want to build the tallest building on Earth? Ambitious but good on yer! This episode will tell you how, starting with how not to. \n\nMost tall buildings are tall and th ...
16-06-2025
CBBC
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.
09-06-2025
CBBC