Tin Can Telephones

 

I made beans on toast today for breakfast, having decided that we need more legumes in our diet – just some fried onion, a bit of curry powder, two tins of butter beans, a tin of tomatoes and a dash of cream – yummy!  (A 50s housewife would have probably cooked her own beans, but they did use some canned products, especially fruit.)

This meant that I had a few cans laying around. What to do?  Seeing it’s Sunday and the children are home ALL day, I thought of telephones to keep them busy for at least 10 minutes.

As I write this late afternoon, they are again playing with them in the garden, although the string has been replaced once , so it was a great idea!

How to do it?

• Get two empty cans – the ones with the top that you pull off have a safer edge than those cut off with an opener.

• Turn both cans upside-down, so that its intact end is facing up, and drive a nail through each centre using a hammer, making a neat hole

• Thread one end of the string through one of the nail holes. Make a BIG knot in the string on the inside of the can, so that the string remains attached to the can. Cut about 10 metres of string (I used rainbow wool) and put the other end into the other can make another big knot. The cans are now tied to either end of the string.

• Hold one tin can (or give it to one child), and give the other tin can to another child. Have them walk away from each other until the string between the cans is taut.

• One speaks into the open end of one tin can while the other listens to the open end of their tin can.
• Expect lots of shouting of ‘can you hear me yet?” and have spare sting on hand for when it breaks.

According to Wikipedia:

When the string is pulled taut and someone speaks into one of the cans, its bottom acts as a diaphragm, converting the sound waves into longitudinal mechanical vibrations which vary the tension of the string. These variations in tension set up waves in the string which travel to the other can, causing its bottom to vibrate in a similar manner as the first can, thus recreating the sound.

So it’s a science lesson recycling, and fun in one.  Enjoy!