M.10.4 Monkey and Hunter

A monkey hanging from the branch of a tree in Africa is spotted by a small game hunter. But this is no ordinary monkey; this monkey knows some physics. He sees that the barrel of the gun is pointed directly at him and reasons that if he lets go of the branch at the right instant, the bullet will pass over his head. But he knows that the sound from the gun will not reach him much before the bullet, and maybe even after, so he decides to watch for the light flash from the gun, knowing that the light reaches him almost instantly, and to let go the instant he sees the flash. Is his reasoning correct?

Our present monkey and hunter is a blow gun. The barrel of the gun is aimed directly at the monkey, held by an electromagnet. As the bullet leaves the muzzle of the blow gun, it breaks a connection that releases the monkey.

The illustration below is available on a viewgraph for overhead projection to the class.

Monkey and Hunter 1986 (1986 Note)

Modern technology gives us a 25mm, laser guided, anti simian cannon. The new monkey and hunter demonstration is on a wheeled table with the elevation of the gun controlled by a crank. The gun is fired by compressed air from a pressure cooker tank. A laser beams through the gun barrel so all can see where the straight line of the gun-aim is directed.