Electroscope

Basically for those of you who do not know, an electroscope is a device which relies on the electrostatic repulsive force that exists between objects of the same charge to deflect foil leaves. In the simplest of explanations, the electroscope works by have a build up of positive or negative charge on its leaves which causes them to repel from each other. Google electroscope if you do not know what one is. I do not want to rehash what the internet already has to offer. But I will explain how I made my own electroscope using simple household items.

1. Salsa Jar

2. Wine Cork

3. Piece of copper wire (roughly 7 inches long)

4. Some epoxy

5. Table salt

6. Aluminum foil

The salt is to absorb unwanted moisture in the air inside the jar; moisture aids in discharging the leaves and minimizes the amplitudes of the displacement of the leaves.

Tools that I used to make my electroscope included:

1. Dremel with a cutoff wheel (needed to cut the salsa jar lid)

2. Q tips to mix the epoxy (or any stick could be used)

3. Drill to make a hole through the cork

4. Razor to cut the aluminum foil

5. Ruler

Step 1.

Trace an outline of the cork onto the center of the lid. Then use the Dremel, or whatever tool you have available to cut as good of a circle you can. Do not worry about getting this part perfect, we will seal the cork lid intersection with epoxy. Make sure the hole for the cork is slightly smaller than the cork; we want to have to force the cork inside.

Step 2.

Push the cork into the lid, about half way. Then mix up some epoxy and apply it heavily around the base of the cork. Enough to seal any large air leaks. (yes, I know air can get through the cork itself)

Step 3.

While the epoxy is setting, cut a piece of aluminum foil 1/2 wide and about 4-6 inches long. The length depends on the jar or bottle you are using. In the end, the foil will hang from the support wire (see step 4) and you want it to have an inch clearance or so with the bottom of the jar. After the foil is cut out, find its mid point and make the cuts outlined below.

Step 4.

The epoxy should be dry enough now.(this depends on what kind you use-follow the instructions on the package) Use your drill to drill a hole through the cork using a bit that is slightly smaller than your wire. After the hole is drilled, push your wire through the cork until about 1.5 inches pokes through. Bend over the last inch of the wire to form the support for the foil.

Step 5.

Fold your foil piece in half and place it on the support wire. I bent mine back and forth a couple of times so it would bend easier.

Step 6.

Place a tablespoon or so of table salt in a metal dish and place it in the oven at 350 degrees F. After a while, you will be able to observe the slat crystals physically shrinking, when most of them are shrunk, dump them out into the bottom of your jar and close the lid with the foil on the support wire. The salt will absorb moisture in the air.

Step 7.

You are done. I first tested mine with a plastic mixing bowl rubbing it on my dog’s fur. He did not seem to mind. It worked the first time for me!

See mine in action, click here.