 And when you let go, this happens! Hello and welcome to another episode of Do Try This At Home brought to you by the Institute of Physics. We're making these films, Parents and Carers, across the UK and Ireland, so that you can explore science together at home with your kids. My name's Nilipha and I'm staying with family in Moira in Northern Ireland and I'm going to show you an activity that is bound to put a spring in your step. What you're going to need is a basketball and if you don't have one, a football will do. You're also going to need a tennis ball. I'm going to try and take Daspers here. You're going to need eye protection, for example some sunglasses and you're going to need a hard surface to bounce the balls off without anything breakable nearby. So I'm going to hand you over to my nephew Ethan, who's out in the garden. To start, drop the tennis ball from shoulder height. It bounces this high. Do exactly the same with the basketball. It bounces higher but not as high as my shoulder. For this next bit, put on eye protection. Line up the centres of the balls. Ask everyone to stand back. That includes you, Jasper. And when you let go, this happens. Going on here and how do you explain it to your family? You can start with one ball. It's round and when I push it, it springs back into shape. It bounces because when I drop it, the ground squashes it and as it springs back into shape, it launches itself and so it bounces up. For the two balls, we drop them together. Basketball bounces a fraction of a second before the tennis ball and because the tennis ball is now bouncing off a surface that is moving upwards, it bounces off with a higher speed and so bounces high. Don't worry if you aren't entirely sure about the science. The main thing is that you enjoy the activity and if you like this one then why not head over to our website where you can find a dozen more that you definitely should try at home. Well that's all for this time so it's goodbye from me and Ethan and it's goodbye from Jasper.