Batteries – Mr. Renwick's Online Classroom

Learning Intentions

To learn how batteries create a voltage difference
To learn how batteries operate in series and in parallel

Media

Kathy Loves Physics & History – How Volta Invented the First Battery Because He Was Jealous of Galvani’s Frog (12:04)

What causes the cockroach leg to move?

Galvani Volta Experiment Replica with Cockroach Leg and DIY battery (2:26)

Volta performed many experiments to see how the human body reacts to electricity.

In his letter describing the pile or battery, Volta (1800) described how with an appropriate positioning of the stimulating electrodes he could produce the corresponding sensation by stimulating the eyes, ears, nose, and tongue at once all together and also produce pain and movement in the lips. He was particularly skillful in producing light sensation by connecting the wires from a battery (or also simply a bimetallic arc) between the mouth and conjunctiva of the eye, which resulted in the experience of light, particularly in a dark room.

Another experiment was described as follows:

Three letters on animal electricity written by Volta to Vassalli during the debate over galvanic current. Among the experiments described is the following: Four insulated individuals form a human chain, the first placing his finger on the tip of the second’s tongue, the second likewise touching the uncovered eyeball of the third, and the third and fourth holding between them in their wet hands a freshly skinned and gutted frog. The first individual holds in his wet hand a sheet of zinc, the last a sheet of silver. When the metal sheets make contact, the electrical circuit is completed; the second individual immediately detects an acid taste on the tip of his tongue, a flash of light appears in the eye of the third individual and the leg of the frog convulses violently.

Why do the kid’s face muscles contract while using the device?

Dr. Ho’s Face Therapy (2:03)