Teacher Resources

1
Teacher Resources

• Laboratory Black line Masters
• Electronic Book
• Skill Sheets

2
Chapter 4.3Gears

• CPO Science
• Integrated Physics Chemistry

3
Developing A Model

• What are gears?
• How do gears work?
• What are some machines that use gears?

4
Key Questions

• How do gears work?
• Do gears fit our definition of a machine from Ch.
  4.1?
• What is the law of gearing?
• How can gear ratios be used to design a specific
  machine?

5
Developing An Experiment

• What variables are there?
• Number of teeth
• Number of turns
• What are we going to test?
• The relationship the teeth of the gear has with
  the number of turns.
• What material will we need?
• What data needs to be collected?
• Number of teeth
• Number of turns

6
Run The Experiment

• Set up the Gears
• Tips
• Make sure the arrows are pointing straight up and
  down.
• Use the smaller of the two gears as the input
  gear.

7
What Did You Learn?

• What are the relationships?
• What did you notice about the number of the input
  output teeth of the gears and the turns?
• Is there any math rule we can use to describe
  this relationship?
• (Input gear turns)(input teeth)
  (output gear turns)(output gears
  teeth)

8
Developing An Experiment

• Do all machines have just 2 gears like a bike?
• What would I need to get a gear ratio of 1100?
• What do you think the gear ratio is for all
  clocks?
• What is the ratio of the machine on the right?

9
Run The Experiment

• Set up the gears as a complex machine.
• Tips
• Make sure the arrows are pointing straight up and
  down.
• Make sure to use the spacers where necessary.

10
Run The Experiment

• Set up the gears as a complex machine with the
  ratios given in the investigation manual part 4.
• Tips
• Make sure the arrows are pointing straight up and
  down.
• Make sure to use the spacers where necessary.

11
Summary

• How do gears work?
• What is the law of gearing?
• How can you design a gear machine that has a
  1100 ratio but occupies very little space?