Week 3 Friction
http://www.slideshare.net/heianapjs/form-2-science-chapter-7
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Classification of Forces
Forces may be classified as either contact forces or forces that act without contact.
Click on the button to explore different examples of forces.
Record the forces that you will be studying in Physics this term. Define each force and provide an example. |
Reading and Note-taking
Friction - a contact force
Find the definition of the terms;
- Non-contact force
- contact force
- friction.
Complete the following sentences.
1. Friction is best described as __________________________________________ .
2. A surface that causes a lot of friction is ____________________ .
3. A surface that doesn't cause a lot of friction is ___________________________ .
4. Friction always acts in the ____________________________________ .
5. Friction produces ____________________ .
6. Friction may be reduced by _______________________ .
7. Polishing and waxing surfaces reduce friction by ________________ .
8. Wheels move more smoothly than shapes that are not round because _______ .
9. Ball bearings reduce friction by ________ .
10. A hovercraft reduces friction by ______________ .
11. Friction can be good when it helps objects move by _________ .
12. When we slip it is because ______________ .
1. Friction is best described as __________________________________________ .
2. A surface that causes a lot of friction is ____________________ .
3. A surface that doesn't cause a lot of friction is ___________________________ .
4. Friction always acts in the ____________________________________ .
5. Friction produces ____________________ .
6. Friction may be reduced by _______________________ .
7. Polishing and waxing surfaces reduce friction by ________________ .
8. Wheels move more smoothly than shapes that are not round because _______ .
9. Ball bearings reduce friction by ________ .
10. A hovercraft reduces friction by ______________ .
11. Friction can be good when it helps objects move by _________ .
12. When we slip it is because ______________ .
Practical Activity
How to convert an Activity into an Investigation.
Question: What effect does the roughness of a surface have on the force of sliding friction?
Draw up a table to present your results.
Construct a graph of your results.
Draw a conclusion from this activity.
Construct a graph of your results.
Draw a conclusion from this activity.
Questions
1. This is a science Activity, not a science Investigation. Explain why.
Let's go through the planning so that we could make it a Science Investigation.
2.What could you choose as the independent variable in this activity?
3. Name the dependent variable and its unit of measurement.
4. Identify three variables that would need to be controlled.
5. Suggest an hypothesis for this Investigation.
6. Explain why several trials are carried out and therefore the averages calculated.
7. Explain why you chose to draw the type of graph that you did.
8. Explain why variables, other than the independent variable, need to be controlled.
9. Explain how to improve the accuracy of an investigation.
10. Explain how to increase the reliability of an investigation.
11. Research three advantages and three disadvantages of friction.
1. This is a science Activity, not a science Investigation. Explain why.
Let's go through the planning so that we could make it a Science Investigation.
2.What could you choose as the independent variable in this activity?
3. Name the dependent variable and its unit of measurement.
4. Identify three variables that would need to be controlled.
5. Suggest an hypothesis for this Investigation.
6. Explain why several trials are carried out and therefore the averages calculated.
7. Explain why you chose to draw the type of graph that you did.
8. Explain why variables, other than the independent variable, need to be controlled.
9. Explain how to improve the accuracy of an investigation.
10. Explain how to increase the reliability of an investigation.
11. Research three advantages and three disadvantages of friction.
Practical Investigation
The effect of changing mass on the force of friction.
Page 261
Aim:
1. Now identify the independent and dependent variables and their units.
2. Write an hypothesis. The hypothesis states the RELATIONSHIP between the independent an the dependant variables. As the independent variable increases, the dependent variable ____________ .
3. List three variables that need to be controlled. Variables other than the independent and the dependent variable have to be kept the same.
Method: Use a ruler and a pencil to draw Figure 7.2.12
Aim:
1. Now identify the independent and dependent variables and their units.
2. Write an hypothesis. The hypothesis states the RELATIONSHIP between the independent an the dependant variables. As the independent variable increases, the dependent variable ____________ .
3. List three variables that need to be controlled. Variables other than the independent and the dependent variable have to be kept the same.
Method: Use a ruler and a pencil to draw Figure 7.2.12
Results:
Complete the questions on page 261