For this one minute Finger Tip you will need a large empty tin can (with a smooth edge where the top was), a nail, a hammer, two elastic bands, a piece of tracing paper and a large piece of black card. Don't forget to see how quickly you can do it with our exclusive timer! The first bit's tricky, and a little bit dangerous. Get an adult to do it for you! You need to punch one hole in the centre of the top of the tin. Use the nail and hammer for this. When you've made the hole, take the nail out. Now, put a piece of tracing paper over the open end of the tin can. Secure it in place with one of the elastic bands. Now turn the tin can onto one side and start to roll it up within the black card. Secure the black card in place with the second elastic band. And that's it! Stop the clock! You've made an upside down viewer. When you look through it, it creates a picture that's the wrong way round, and upside down! Look through the tunnel you made with the black card, onto the "screen" made by the tracing paper. You need a lot of light to make this work, so try it on a bright day. You can improve it by painting the inside of the tin black. And if you haven't got a piece of black card handy, try it this way!