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The Electric Human

In the Last project Liquid Conductivity Tester in Amplifiers section, we asked you to think of some other things that can conduct electricity. Did you include yourself?

It's true, you can conduct electricity just like a wire. This Project will let you measure how well your body can conduct electricity. Don't worry, the electricity will be so small you won't even know it's there. But you can measure it using the sensitive circuit in this Project.

When you finish making the wiring connections, put the power on. Adjust the Control Knob so that the Meter points to zero.

Now take one of the long wires in each hand and grasp them by their exposed ends. Now squeeze the exposed ends and watch the Meter. What happens?

The Meter moved, and it did so because electricity flowed through your body from one long wire to the other. The harder you squeeze the exposed ends of the long wires, the more the Meter will move. Can you guess why?

You can also make the Meter move more by adjusting the Control. (You've probably already figured out that the Control works by controlling the amount of electricity that flows through a circuit, haven't you?)

It's really not too surprising that electricity can flow through your body. We've already seen that water can carry electricity, and your body is mostly water! (Didn't know that eh? Well, now you do!)

A more complicated version of this circuit is used in lie detectors. When a person lies, they are usually nervous. They perspire more, and this makes it easier for their body to conduct electricity. So if someone's body lets more electricity flow than normal, it's often a good sign that they're not telling the truth.

Try this Project as a lie detector with your friends. How well does it work? (And here's an exercise for your brain: You've probably heard of "voltage" and "current". Have any idea what they are? Which one do you think your body conducted? Make a mental note...)

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