Activity 7.2:
Aim: To test the existence of electrostatic charges on certain materials.
Materials: Balloon, pieces of shredded paper and stream of running tap water
Apparatus: Polythene rod, cellulose acetate strip and woollen cloth
Instruction
1. Rub a polythene rod with a woollen cloth.
2. Hold the rod close to pieces of shredded paper (Photograph 7.3) and record your observation.
3. Repeat step 1.
4. Hold the rod close to a small stream of running tap water and record your observation.
5. Repeat steps 1 to 4 using a cellulose acetate strip and a balloon to replace the polythene rod.
Questions
1. Give an inference for your observation.
2. What other methods can be used to test the existence of electrostatic charges on the balloon?
Explain the steps taken.
Answer:
1. The pieces of shredded paper are attracted to the object because the object that has been rubbed with woollen cloth will have electrostatic effect.
2.
i. Rub 2 balloons filled with air against dry hair.
ii. After a few minutes, place the balloons close to each other.
iii. The balloons will repel each other.
iv. This shows that both balloons have collected the same charges when rubbed with the hair.
Aim: To test the existence of electrostatic charges on certain materials.
Materials: Balloon, pieces of shredded paper and stream of running tap water
Apparatus: Polythene rod, cellulose acetate strip and woollen cloth
Instruction
1. Rub a polythene rod with a woollen cloth.
2. Hold the rod close to pieces of shredded paper (Photograph 7.3) and record your observation.
3. Repeat step 1.
4. Hold the rod close to a small stream of running tap water and record your observation.
5. Repeat steps 1 to 4 using a cellulose acetate strip and a balloon to replace the polythene rod.
Questions
1. Give an inference for your observation.
2. What other methods can be used to test the existence of electrostatic charges on the balloon?
Explain the steps taken.
Answer:
1. The pieces of shredded paper are attracted to the object because the object that has been rubbed with woollen cloth will have electrostatic effect.
2.
i. Rub 2 balloons filled with air against dry hair.
ii. After a few minutes, place the balloons close to each other.
iii. The balloons will repel each other.
iv. This shows that both balloons have collected the same charges when rubbed with the hair.