A Longer Path for Sound
You will need: Two wooden matchbox trays, thread, wooden match-sticks, scissors, nail.
Use two strongly made matchbox trays and make a small hole in the bottom of each with a nail. Pass one end of a long length of strong thread through one of the holes and tie a matchstick to the end of the thread so that it is inside the tray. Repeat this with another matchbox tray and matchstick on the other end of the same thread. Pull gently, but firmly, on the matchbox trays so that both matchsticks are tight on the inside of the trays.
Let a friend take one tray while you hold the other.
Walk apart so that the thread is taut-but do not pull so hard that the bottoms of the trays are wrenched loose. You must also ensure that nothing is touching the length of thread.
Speak into the tray. Your voice will travel along the path formed by the thread and will be heard quite plainly by your friend at the other end..
You must, of course, use the trays in turn, first as earphones and then as mouthpieces to speak into. If you stretch a long thread out in the garden you will be surprised to find how clearly your voice will carry. But again, take care that nothing (not even a twig or leaf) touches the thread.