At-Home Activities

Test different kinds of plastic wrap to discover which kind sticks best to bowls and other kinds of containers. How well does each plastic wrap stick to ceramic, glass, plastic or metal bowls?

Repeat this investigation at home to demonstrate to family members what you have learned about electric charges.

Rub different types of materials and clothing together to create a charge. Rub a plastic comb on some fur. Place the comb on a smooth surface so that it can easily spin. Bring each of the charged materials close to the charged comb. Describe to family members what is happening.

Create your own electrostatic series by carrying out experiments with different materials found in your home. Use two or three materials that are in the electrostatic series in Table 1 (page 275); this will provide a reference for identifying the kind of charge on the substances in your list. (Note: Some materials may be very close to one another in the list and may be difficult to charge.)

Make your own pith ball electroscope by tying a piece of cotton to the modified hook on a coat hanger that has been bent such that it will be self-supporting. (See illustration on p. 277 of your textbook.) A small piece of cereal (such as puffed wheat or rice) can be used instead of the pith ball used in the science classroom. Set up apparatus similar to that used in the textbook investigation to test different materials and identify if they are conductors or insulators.

Find out in which rooms in your home, and under what conditions, you experience static shocks due to charging. Do you get the same kind of electric shocks from metal doorknobs as from wooden or plastic doorknobs? Do you get static shocks when properly using any kinds of equipment in your home? Make a list of these observations and share them with classmates and family members. What are the possible explanations?

Compare the movement of electric charge on the surface of an ordinary rubber balloon to that on the surface of a party balloon that has a metal film covered surface. Inflate both balloons and rub each one on your hair. Predict what will happen when each balloon is placed against different kinds of wall surfaces. Follow the same procedure as you did in step 1 of the investigation on page 270. What do you notice about the distribution of electric charge on the balloon surfaces? What is another way to check the distribution of electric charge on the balloon surfaces?

Try these two experiments at a time of year when you commonly receive static shocks by touching a doorknob after walking across a carpeted room. (This usually occurs in winter.)

1. After you have received a static shock, use a long piece of wire, bare at both ends, and wrap one end of the wire to part of a metal water tap. Hold the other end of the wire in one hand, then repeat what you did previously to become charged (walk across a carpeted room). Touch the doorknob with the other hand. Describe what happens and why.
2. After you have received a static shock, obtain a pointed piece of metal or a piece of wire. Hold on to the wire in one hand and repeat what you did previously to become charged (walk across a carpeted room). Then touch the doorknob with the other hand. Describe what happens and why.

Inquire among family members, relatives and acquaintances about careers in physics-related, engineering-related and technology-related fields of employment.

1. Charge the vertical glass surface of a large window by rubbing it vigorously with a cloth. Then drop small pieces of lint, short pieces of fine cotton, or some tiny pieces of paper just in front of the rubbed section of the window. What happens and why?
2. If you home has an electrostatic air cleaner, read the operating manual to learn how it works.

Try making your own metal leaf electroscope. Use the metal coverings from candy wrappers or aluminum covering from mint rolls as the metal leaves. Observe the construction of one of the metal leaf electroscopes used in class to determine what other parts are needed and how they should be assembled. Test your electroscope and compare its performance with the one used in class. How could you improve your electroscope?

You can calculate how far away you are from a group of lightning-producing clouds by using the flash of the lightning and the sound of the thunder:Sound travels at about 330 m/s (332 m/s at 0° C). That translates into approximately a distance of one kilometre (1km) every three seconds (3 s). From the instant you see the flash, begin counting the time in seconds. When you hear the thunder produced by the lightning stroke, stop counting. Divide the time in seconds by 3. The answer represents your distance (in kilometres) from the source of the lightning.

This technique can be very useful when lightning is in the vicinity. Sometimes, however, it is difficult to tell if the lightning storm is coming directly toward you or if it is going to pass at a safe distance.

If you have access to a cellular phone or some other device with an aerial, try using it in different locations in a house, apartment block, modern office building or underground garage. What effects do different types of building construction have on the performance of the device?

The Chapter Review (pp. 294-295) in your textbook lists all the Key Expectations you have covered in the chapter and identifies the specific lessons in which the knowledge and skills have been developed.

You can use the Key Expectations list to help you create a personal study guide in preparation for an end-of-chapter test:

1. Copy down the list of learning expectations from your textbook.
2. For each learning expectation, locate the appropriate lesson(s) in the unit where the expectation was covered. These are identified in parentheses at the end of each expectation (e.g., 9.2).
3. Flip to the appropriate lesson(s) for each expectation and make study notes of the key ideas or skills you learned.