Levers & Pulleys
Investigation 3
Part 2
Two-Pulley Systems
Students investigate how two pulleys can be used together. Students then diagram the four pulley systems that can be assembled using one or two pulleys.
3. Lesson set up and Management
1. Systems
- 1.2 Structure of Systems
- 1.2.1 Systems Approach
Describe how the parts of a system interact and influence each other.
(ST01, STI02, STI03, & STI04) - 1.3 Changes in Systems
- 1.3.1 Nature of Forces
Know the factors that determine the strength and interactions of the various forces.
(CH01 1.3.1)
2. Inquiry
- 2.1 Investigating Systems
- 2.1.1 Questioning
Generate questions that can be answered through scientific investigations.
(IN01 2.1.1) - 2.1.4 Modeling
Correlate models of the behavior of objects, events, or processes to the behavior of the actual things under investigation; test models by predicting and observing actual behaviors or processes.
(IN04 2.1.4)
Two pulley systems often use one fixed pulley and one movable pulley.
A two-pulley system in which effort is applied upward provides a greater mechanical advantage than one in which effort is applied downward.
3. Lesson set up and Management
Materials:
If desired, make an overhead of the page labeled “Response Sheet-Pulleys”.
Student Management:
Have student(s) sort materials or make a materials list on the board; have one person from each pair gather the materials.
Specific students can be designated as “materials persons”.
Be sure to inspect pulleys for accuracy and set scales to zero.
Review the use of scales with students.
Be prepared to explain what 30kg means before students do Worksheet 19.
Have students set up each pulley system before diagramming/drawing it.
In Step 9, you might want to bring in examples of simple machines.
Make overhead transparencies of all Student Work Sheets to aid in review and discussion.
Read Teacher and Student background sections before doing the investigations.
Writing Support:
Write about Sparky and his troop.
Research Block and Tackle.
Write a story about how the pulley got its name.
Reading Support:
See Dear Boss in the FOSS manual’s Science Stories Folio.