Electricity: Electric Charge and Resistance
ELECTRICITY I. DISCOVER OF ELECTRICITY
About 600 B.C., Thales, a Greek philosopher and scientist, observed that a piece of amber attracted small bits of “paper” or very thin wood shavings after it was rubbed with wool. He had discovered, in effect, static electricity. William Gilbert, an English scientist in the sixteenth century, found that many other different materials could be made to act like amber. Whenever these objects were rubbed against each other, they were able to attract each other light objects. He called this strange behavior electricity, from the Greek word elektron, meaning amber.
II. WHAT IS STATIC ELECTRICITY?
How is electricity produced? Have you ever noticed how your hair stands straight and stiff when you comb it vigorously on a dry, cold day? Or how difficult it is to remove dust particles from your comb? Your hair and the comb become charged by rubbing. This stationary electric charge is described as static electricity.
Activity 1.
Rub a plastic sheet with flannel and then hold the plastic sheet near Styrofoam bits. What do you observe?
From the observations made, you can conclude that rubbing produces static electricity on the rubbed objects. The two objects, when rubbed against each other, become electrified. We can described them as being charged.
Activity 2. Prepare a simple electroscope, using the following materials: iron stand, silk thread, small Styrofoam ball covered with aluminum foil.
The electroscope is a simple instrument that can help detect the presence of static electricity. If a glass rod were rubbed with a piece of cloth then placed near the ball, the ball will be attracted to the rod. After a few seconds of contact with the rod, the ball will be repelled. Why? If a plastic rod were rubbed with flannel or wool, and the rod placed closed to the ball, the same result will be observed. Both the silk and woolen pieces of cloth also show signs of having been electrified when placed closed to the electroscope.
The
About 600 B.C., Thales, a Greek philosopher and scientist, observed that a piece of amber attracted small bits of “paper” or very thin wood shavings after it was rubbed with wool. He had discovered, in effect, static electricity. William Gilbert, an English scientist in the sixteenth century, found that many other different materials could be made to act like amber. Whenever these objects were rubbed against each other, they were able to attract each other light objects. He called this strange behavior electricity, from the Greek word elektron, meaning amber.
II. WHAT IS STATIC ELECTRICITY?
How is electricity produced? Have you ever noticed how your hair stands straight and stiff when you comb it vigorously on a dry, cold day? Or how difficult it is to remove dust particles from your comb? Your hair and the comb become charged by rubbing. This stationary electric charge is described as static electricity.
Activity 1.
Rub a plastic sheet with flannel and then hold the plastic sheet near Styrofoam bits. What do you observe?
From the observations made, you can conclude that rubbing produces static electricity on the rubbed objects. The two objects, when rubbed against each other, become electrified. We can described them as being charged.
Activity 2. Prepare a simple electroscope, using the following materials: iron stand, silk thread, small Styrofoam ball covered with aluminum foil.
The electroscope is a simple instrument that can help detect the presence of static electricity. If a glass rod were rubbed with a piece of cloth then placed near the ball, the ball will be attracted to the rod. After a few seconds of contact with the rod, the ball will be repelled. Why? If a plastic rod were rubbed with flannel or wool, and the rod placed closed to the ball, the same result will be observed. Both the silk and woolen pieces of cloth also show signs of having been electrified when placed closed to the electroscope.
The