Static Electricity Labs

STATIC ELECTRICITY LABS

Experiment 1: Building an Electroscope

An electroscope is a device that detects electrical charge.

Divide your group into 2 pairs. One pair will build Electroscope A, while the other pair will construct Electroscope B.

Names: ______

Purpose:

______

Part A: Electroscope Cup

Materials:

 One small cup (glass or paper)

 One plastic drinking straw with flexible end

 Tape

 Aluminum foil

Procedure:

1. Place a straw into a small cup. The flexible part of the straw should be at the top, and the straw should be bent.

2. Cut two small strips of aluminum foil, about 6 cm long and 1 cm wide.

3. Tape the strips onto the bent part of the straw, so that they're next to each other, but not touching. They should hang straight down from the bent arm of the straw. The electroscope is complete and ready for use.

Part B: Lightning Rod Electroscope Materials:

 One small plastic cup  Tape  Aluminum foil  Paper Clip  Balloon  Scissors  Push Pin

Procedure:

1. Using the push-pin, create a small hole in the bottom of the plastic cup through which the paper clip will later be inserted.

2. Cut two strips of aluminum foil that measure roughly 5 mm by 4 cm. Use the end of a paper clip or your push pin to punch small holes in the one end of each foil strip.

3. Unfold a paperclip so that it looks like a long J, and hang the foil strips, called leaves, on the curved end of the J. Smooth out the leaves so that they hang straight and next to each other, but do not try to press them into one other.

4. Holding the cup upside‐down, insert the straight part of the J paper clip through the hole in the cup, so the leaves hang inside the upside down cup without touching the table or desk top. Secure the paperclip in place using plastic tape.

5. Roll some aluminum foil into a ball and place the ball on the top of the paperclip that is sticking out from the cup. The electroscope is complete and ready for use. Experiment 2: Charging by Friction

1) Read through the procedure carefully.

2) Determine which materials you will use. Justify your choices.

3) List the safety rules that you will follow.

4) DO NOT START THE LAB UNTIL YOUR TEACHER HAS INITIALED NEXT TO YOUR MATERIALS LIST AND SAFETY.

5) You will be marked on the correct choice of materials and safety rules.

Materials Data Table 1: Materials Materials Justification

Safety Rules:

______

______Procedure:

1) Tear a quarter sheet of paper into small pieces.

2) Charge a black rubber rod (ebonite rod) by rubbing it with a piece of wool.

3) Pick up the pieces of paper with the rod.

4) Count how many pieces of paper you were able to pick up.

5) Repeat Steps 2-4 but use a plastic rod and fur.

6) Repeat Steps 2-4 using a glass rod and silk.

Observations:

Data Table 2: Observations Materials Observations (# of papers picked up) Experiment 3: Charging by Conduction

Complete the Background Information and Procedure. Have it initialed by your teacher before you begin the lab.

Background Information:

What does the word “conduction” mean? Identify some similar words and determine the meaning of “conduction”.

______

Purpose: What do you think “Charging by Conduction” means? What are you required to do in this lab?

______

Materials:

 Electroscope  Ebonite rod  Wool  Clear acrylic rod  Metal rod (aluminum foil)

Procedure:

1. Ground the charge on your electroscope. Touch the tip of the metal to remove extra electrons. (The electrons are traveling through you to the ground) 2. Rub the ebonite rod with some wool. (You should hear it crackling). 3. Bring the rod towards the electroscope and touch the metal. 4. Remove the rod. 5. Observe what happens to the metal leaves. 6. Determine how you can remove the charge from the electroscope (make the metal leaves come together). 7. Charge the electroscope. Touch the charged electroscope with an uncharged metal rod. Record your observations; draw what you see. 8. Re-charge the electroscope (if necessary) and touch it with the (uncharged) acrylic rod. Record your observations; draw what you see. Observations: (Diagrams)

Step 7:

Step 8: Experiment 4: Charging by Induction

Complete the Background Information and Procedure. Have it initialed by your teacher before you begin the lab.

Background Information:

“Induce” means to “bring on” or “to cause”. When we charge by induction what are we bringing on or causing?

______

Purpose: What do you think “Charging by Induction” means? What are you required to do in this lab?

______

Materials:

 Electroscope  Ebonite rod  Fur

Procedure:

1. Use the fur or wool to charge the ebonite rod.

2. Move the rod close to the electroscope but DO NOT TOUCH THE ELECTROSCOPE.

3. Ground the ball at the top of the electroscope with your finger.

4. Remove your finger.

5. Move the rod away from the electroscope. Record your observations. Observations (Diagrams):

Step 5: Analysis and Interpretation :

Electroscope Design:

1. Compare the two electroscopes. Which has a better design? Give specific examples from today’s lab.

______

2. Describe what you would improve in the design of your electroscope.

______

3. Determine how the electroscope detects charge.

______

Charging by Friction:

4. Demonstrate your understanding of how items are charged by friction by drawing in the space provided. 5. Some materials are “insulators”, they hold onto electrons tightly. Other materials are “conductors” which allow electrons to flow through them easily. Use your observations to determine which materials are insulators and which are conductors.

______

Charging by Conduction:

6. How did you determine if your electroscope was charged?

______

7. Why did you touch the electroscope? Are you a conductor or an insulator?

______

Charging by Induction:

8. Only electrons can move out of an atom (protons and neutrons stay in the nucleus). Explain how charging by induction causes a neutral object to act like a charged object. You may wish to include diagrams.

______

______SUMMARY: STATIC ELECTRICITY LABS Scientists’ Ideas Comparison Charts In the “Our Ideas” columns, summarize what you have learned in each section of the static electricity labs. Use your text and determine if your ideas match with the “Scientists’ Ideas” record any discrepancies. What do you agree with? Why do you disagree?

Charging by Friction Our Ideas Scientists’ Ideas

Charging by Conduction Our Ideas Scientists’ Ideas

Charging by Induction Our Ideas Scientists’ Ideas