Physical Science

 

Simple and Compound Machines
(see also: Light Up Our World)

(Related information - Infusing Brain Research: Simple Machines Unit)
Standard Statement:
3.4.7 C - Identify and explain the principles of force and motion.

Content Objectives:
Students will be able to:

1.    Learn the concepts of the lever arm, fulcrum, load and effort.

2.    Experience one advantage that can be gained by using a lever-reduced effort.

Assessment Strategies:

1.    Teacher will bring in several simple tools: nutcracker, stapler, claw hammer, scissors and so on. Children will identify lever arms, fulcrum, load and effort.

2.   Children will correctly diagram and label lever systems that they make.

Procedures: 

1.    Plan to begin the activity by using one or more real-world levers.

2.    Challenge the students to lift you with one-hand.

3.    Challenge the students to open a bottle (no twist tops) or open a putty can with their bare hands. 

4.    Use a red brick (fulcrum) or a similar size piece of wood and a 2-M-long 2 x 6 (lever arm) with the fulcrum close to the end of the lever arm that you will stand on. Students should be able to lift you with one hand (seesaw).

      Use a bottle opener to open the bottle and screwdriver to open the putty can. Tell the students that these are tools that people use to make work easier. They are called levers. Levers are used to lift weight or overcome a resistance. Levers give us an advantage   by making work easier. 

5.    Children will work in pairs.

6.    Introduce the lever setup. Develop lever vocabulary as you set up a demonstration system.

7.    Using a wooden meter stick as a lever arm, a small wooden block (fulcrum, the point around which the lever arm pivots) and plastic mass pieces (weights) as the load, demonstrate the simple lever setup by placing the load at one end of the lever arm and using your finger to supply the push pull to or move the load.

      LEVER ARM              
                                Effort

                    

8.    Students work in pairs. Have enough materials for them to openly explore their own lever set-ups varying the position of their loads and fulcrums and the masses of their loads. Have them list any questions or comments that they may have on sticky notes.

9.    When finished, have them bring their sticky notes to post on chart paper. Separate questions and comments. 

10.  Reflect with students on questions and comments in large group. Save questions and comments for future use.  

11.  Apply - Bring several simple tools to class: nutcracker, stapler, hammer, scissors and so on and have children identify fulcrum, force, lever and load.

Suggested Level:
Grades 5-7

Standard Category:
3.4 – Physical Science, Chemistry and Physics

Materials:
1 - 2 meter 2” x 6” board

1 red brick

Simple lever tools

Chart paper

Sticky notes

Per pair of students:

 1 meter stick

 1 small wooden

 block

 1 set of mass pieces

 (weights)

Instructional Strategies:
Inquiry

Demonstration

Guided lab practice

Discussion

Reflection

Application

Related Concepts:
Ideal and actual mechanical advantage

Efficiency