Do Try This at Home episode 3: Shrinking coin

2D… or not 2D? Hello and welcome to Do Try This at Home brought to you by the Institute of Physics. We’re making these films because we want to help parents and carers in the UK and Ireland get their kids excited and curious about the world around them – and you don’t even need to leave your home to do it. My name is Lucy and you’re very welcome to join me in my home. I’ve managed to find a quiet enough corner so you can join me on a journey to the third dimension in a demonstration that I like to call the Amazing Shrinking Coin. For this demonstration you’ll need a 10 Cent coin and a 2 Euro coin.

If you’re in the UK 00:42 - you can switch this with a 1p and 2p coin so long as you have one small coin and one large coin to work with. You’ll also need a pencil, a pair of scissors and some small pieces of paper. To get started we’re going to take our 10 Cent coin and we’re going to lay it in the centre of the paper. Using our pencil we’re going to trace around the coin. Next we’re going to cut from the centre of the circle so that we’re left with a piece of paper with hole in the middle.

Now you can demonstrate to your family that the 10 Cent coin can easily slip 01:21 - through the hole. Challenge them to try to do that with a 2 Euro coin. So see if they can get the 2 Euro coin to fit into the 10 Cent size hole without ripping or tearing the paper. It also might be a nice idea for everyone joining in if everyone had their own coin and piece of holey paper so they can try it a few times. And then you can show them how it’s really done. Bending the paper creates a third dimension, so we can turn our round hole on a flat piece of paper into a slit across the bottom of a curved piece of paper. Of course our problem is still there.

These points here and here are 02:00 - still too close together to allow the coin just to slip through so this is where the creative bit comes in. Because we have folded the paper we can very gently pull these points apart to allow the paper to fold like this and so it can get wider without tearing to let the coin slip through. Just like that old saying 2D or not 2D. A top tip if you’re doing this with your family is to use fresh sheets of paper because the folds in the paper might give them a clue. This demonstration is all about getting your family to think like a scientist and to help them improve their problem-solving skills. If you’ve enjoyed watching this video then do give it a like and then maybe head on over to our website.

Thank you so much for watching and see you 02:43 - next time!.