How to Use an Electroscope

Bending Water

Materials Used

A hard plastic comb

A wool sweater

A faucet with running water

A balloon

I rubbed the comb against a wool sweater. I turned on the faucet to a slow, running stream. I held the comb near the water but not directly under it. The water stream begin to change its shape from a straight up-and-down line to a bent arc. Next, I rubbed the balloon on the sweater. The water did the same in the presence of the balloon.

Observations

Both the comb and the water produced a subtle but visible effect. Using a thin stream was necessary to visualize the bend.

Given that water is neutral in terms of its electrical charge and both the comb and the balloon had been briefly charged with static electricity, the object caused the water to bend. "The electrical charge develops when two objects are rubbed against one another. When the objects are rubbed together, some electrons (charged components of atoms) jump from one object to the other. The object that loses the electrons becomes positively charged, while the object that they jump to becomes negatively charged. The nature of the objects has a large effect on how many electrons move. This determines how large an electrical charge accumulates in the objects. Hair and nylon are particularly good at acquiring charge when they are rubbed together" ("Bending water," 2015). Humidity can also affect the transmission of a charge; this is best conducted under dry conditions.

Reference

Bending water. (2015). Home Experiments. Retrieved from:

http://scifun.chem.wisc.edu/homeexpts/BENDWATER.html

Building and using an electroscope

Materials Used

Glass jar

Foil

Paper clip

Cardboard

Scissors

Tape

Procedure

I measured and cut the cardboard into a circle. After bending the clip into a J-shape, I inserted the clip through the center of the cardboard. I cut a small 'leaf' shape in the foil and threaded it through the hook of the clip. I placed the cardboard on top of the jar and used tape to secure it with the hook inside the jar. I crumpled the rest of the foil and secured it to the top.

Observations

As with the charged stream of water, the leaves of the electroscope respond by moving away from one another when exposed to various sources of static electricity, including a 'charged' comb and balloon that have been rubbed on a wool sweater.