## Unit of Study: Simple Machines

Unit of Study: Simple Machines Title of Lesson: Pulleys Lesson Duration: 70 min Developed by: Mr. Heidke Subject Area(s):Physical Science Informatio...
Author: Maria Simon
Unit of Study: Simple Machines Title of Lesson: Pulleys

Lesson Duration: 70 min

Developed by: Mr. Heidke Subject Area(s):Physical Science Information Literacy Standards:

Grade Level(s): 9th Content Specific Standards:

A.8.4 Use a computer and communications software to access and transmit information B.8.3 Locate and access information sources B.8.6 Interpret and use information to solve the problem or answer the question C.12.4 Demonstrate self-motivation and increasing responsibility for their learning D.8.1 Participate productively in workgroups or other collaborative learning environments D.8.2 Use information, media, and technology in a responsible manner

D.8.6 While conducting investigations, explain the motion of objects using concepts of speed, velocity, acceleration, friction, momentum, and changes over time, among others, and apply these concepts and explanations to real-life situations outside the classroom D.8.7 While conducting investigations of common physical and chemical interactions occurring in the laboratory and the outside world, use commonly accepted definitions of energy and the idea of energy conservation D.12.11 Using the science themes*, explain* common occurrences in the physical world NJSD 28. Identify the six simple machines and model their uses

Stated Objective(s): (Include the focused Instructional Strategy-see chart on page 13)

In this lesson students will explore pulley systems. They will have a basic understanding of the different types of pulleys, how they work, and how to calculate the mechanical advantage of each pulley system. Students will use collaborative learning (groups), nonlinguistic representation (computer simulations), and data collection, to summarize and generate a hypothesis.

Materials: Classroom set up Pulley systems, Notes Pulley Lab Simulations Web Site 1: http://www.explorelearning.com/index.cfm?method=cResource.dspView&ResourceID=572 Pulley Lab Simulations Web Site 2: http://www.explorelearning.com/index.cfm?method=cResource.dspView&ResourceID=643 Pulley Lab data collection Worksheet and students personal lab journal. Explanation of Lesson: Students will look at actually pulley set ups on display in the classroom and discuss the systems via notes and lecture. The students will receive lab worksheets with instructions and data tables and work in groups of three. Students will use the website simulations to explore four pulley setups. They will collect data and calculate the Ideal and Actual mechanical advantages of each pulley system. Students will also use the simulations and their data to answer questions and create graphical representations. The second simulation involves using pulleys to lift objects up two a third floor window. Students will need to figure out how many people it will require, and the advantage of using different pulley systems to accomplish their task. Students will also use the simulations to answer web based questions.

Student Assessment: Students will complete the data table on their lab sheet and calculate the Ideal and Actual Mechanical advantages for each of the four pulley systems. Students will then graph Effort force versus distance force and AMA versus effort distance and describe the relationships. Students will answer web based and lab sheet questions and compile their data and answers in lab journal. The group will also type a paragraph describing how they lifted the furniture into the house and discuss the advantages, disadvantages, and applications of the pulley system. The paragraph will be emailed to the instructor.

Physics Lab: Pulley System (Simulation)

Purpose:

Name____________________ Mod: ____ Date: __________

To determine the ideal and actual mechanical advantage of a pulley system.

Materials: Web Site: http://www.explorelearning.com/index Procedure: PART A 1. Open the Pulley Lab Gizmo 2. Pick a weight for the pulley, make sure the pulley is at 100% efficiency 3. Pull the scale with the mouse until it brings the mass all the way up, record the values in the table below. Repeat step 3 until you have completed all of the setups. 4. Once you are done with the experiment, calculate the ideal and actual mechanical advantage for each pulley

Set up

Resistance Force (N)

Effor t Force (N)

Resistanc e Distance (m)

Effort Distanc e (m)

Strand s of string

1Fixed 1Fix 1 mov 2Fix 2 mov 3Fix 3 mov

Setup 1 Setup 2 Setup 3 Setup 4 Materials: Web Site: http://www.explorelearning.com/index Procedure: PART B 1. Open the Pulleys Gizmo 2. Use the proper set up to lift the object into the building, record the number of people necessary to complete the task 3. Make sure to put the object in the building 4. Answer the online questions!

Set up

Arm Chair

Safe

Piano

Height of object (m)

Rope on ground (m)

1Fixed 1Fix 1 mov 2Fix 2 mov 3Fix 3 mov 5.

Create the following graphs for part A

Effort Force vs. Effort Distance Distance

Questions: 1.

What happens to the effort force as the number of supporting strands is increased?

2.

What happens to the effort distance as the number of supporting strands is increased?

3.

What is the relationship between the effort force and the effort distance?

4.

What is the relationship between the ideal mechanical advantage and the number of supporting strands?

5.

What are two example of where pulley systems are used?

6.Which pulley system will allow the armchair to be lifted with the least amount of effort? A. System A B. System B C. System C D. System D

7. A pulley system is helpful because it decreases the ______________________. A. amount of effort needed to lift an object

B. amount of rope needed to lift an object

C. weight of the object

D. height that the object needs to be lifted

8. What is the ideal mechanical advantage of the pulley system shown below?

9. In the situation shown below, the safe is 5 meters off the ground. How much rope is lying on the ground? a. 5m b. 10m c. 20m d. 40m

10. Four people are needed to lift a TV set with a single fixed pulley. How many people will be needed to lift the same TV set with a 2 fixed, 2 moveable pulley system? (Ignore friction.) WHY? a. 1

b. 2

c. 4

d. 8