1. 10 15 5 Year: 9 Sci Unit Topic: Accidents and Gadgets
Lesson Topic: Pulleys
Lesson Outcomes/Main Ideas:
1. How pulleys work
2. Mechanical Advantage
Advance Organiser: PPT AGLP08 page 3 (Pulley Rules) on board for S to copy into books.
Housekeeping
Action
Resources
Time
House: Role whilst S copy PPT into book
Remind S about graph homework from Friday – due Wednesday
PPT AGLP08 – Pulleys 10
Introduction – Story about using a single pulley to lift stairs up to
the front door of my relocated house.
explain/point out distances the load and force moves
1 Fixed Pulley – S copy title, diagram and table into books
T demo, S helpers take readings, and put result on
board.
Pulley demo set up – stand, clamp, pulleys, masses (10x50g), string 15
2 Movable Pulley – S copy title, diagram and table into books
A/A
3 Combined Pulley – S copy title, diagram and table into books
End T explain/point out the load and force distances moved
Word Maze
Pulleys and masses (xtra to demos) for S to make own pulley systems. 5
Extension Activity: S to work on other pulley set ups.
Homework Set: Simple Machines worksheet.

2. Lesson Thoughts
Next: Run through the demos, then get S to design own pulley, work out it’s MA, then build it.
This might require much more than one lesson!!
Need worksheets – basically pages 4-6 plus a blank table for S design (a missing slide 7).
I could – run through the demos, then hand out the worksheets, for S to work through themselves. This should give them more time to work on their own pulley system.
Actually if I have a separate sheet, do I need everything on the slide??
Yes - because S will see on the whiteboard what they see on their paper, and I can write on the white board.
No - because it is on the sheet, and it clutters up the slide
Story - stairs up to my relocated house.

3. Pulley Rules Mechanical Advantage
Combining more than one pulley means that big weights can be lifted with very little effort.
BUT for each metre raised, much more rope has to be pulled through.
Mechanical Advantage
Count the number of rope sections.
If the rope is pulled up , the number of rope sections = the MA (Mechanical Advantage).
If the rope is pulled down , then minus 1 from the number of rope sections. This number then = MA (Mechanical Advantage).
Divide the weight to be lifted by the mechanical advantage to find out how much force is required to lift.

4. Pulleys 1: Fixed Watch the demonstration.
Work out the MA (Mechanical Advantage)
Number of strings = N
If Pull up , p = 0
If Pull down , p = 1
MA = N - p
Note: Effort = Mass/MA
Take spring balance
measurements as follows:
Effort
Mass MA Mass Balance
/MA ?
What do you notice?
Mass

5. Pulleys 2: Movable Watch the demonstration.
Work out the MA (Mechanical Advantage)
Number of strings = N
If Pull up , p = 0
If Pull down , p = 1
MA = N - p
Note: Effort = Mass/MA
Take spring balance
measurements as follows:
Effort
Mass MA Mass Balance
/MA ?
300
500
What do you notice?
Mass

6. Pulleys 3: Combined Watch the demonstration.
Work out the MA (Mechanical Advantage)
Number of strings = N
If Pull up , p = 0
If Pull down , p = 1
MA = N - p
Note: Effort = Mass/MA
Take spring balance
measurements as follows:
Effort
Mass MA Mass Balance
/MA
? ? ?
300
500
What do you notice?
Mass

7. Pulleys 4: Your Choice
Equipment: pulleys (single or double), string, 1 spring balance
Design a pulley system using
more than two pulleys:
Work out the MA and
how much effort you will need.
Build your pulley system.
Take spring balance
measurements as follows:
Effort
Mass MA Mass Balance
/MA
? ? ?
300
500
What do you notice?
How many pulleys?
Pull Up ?
? ?
Mass
Pull Down ?
How many pulleys?