A bull-roarer out of a tub lid

You need

• a soft plastic yogurt or ice-cream lid
• scissors
• a hole punch
• three feet of kite string
• and one grown-up to say yes before you start

About half an hour. Everything on that list came out of a kitchen, which is the rule these pages are written to.

Steps

1. Cut the lid into a long oval, like a canoe — as long as your hand, half as wide. Round every corner. No points.
2. Punch one hole a thumb's width in from one end. Smooth it if it is rough. If the plastic cracks, start again with a softer lid; a cracked one will come apart in the air.
3. Thread the string through and tie a knot you trust. Then tie it again.
4. Check the string every single time before you swing it. If it is frayed, fuzzy, or has a kink in it, cut that bit off and re-tie. A string that lets go turns this into a thrown object.
5. Go outside, into open space, away from windows, and take everybody else outside the circle. Stand with your arm straight out and turn all the way round. If your hand touches anything at all, you are in the wrong place.
6. One person swings. Everybody else stands well outside the circle and counts. Nobody stands behind you, because behind you is where it goes.
7. Hold the end of the string and swing the lid over your head, slowly at first. It will hum, then buzz, then roar. Faster is louder. A slight twist in the oval makes it much louder than a flat one, which is worth finding out for yourself. A longer string makes a lower note, and the limit on how long is in the box below.
8. Nine swings, then stop, then swap. That is Holly's rule too. She has nine good calls in her, and the ninth is always the important one — and it is a rule about your ears as much as hers, because this thing gets loud enough to be worth taking seriously.