04 Dec What do cantilevers and pulling nails have in common?
A.CED.1 Create equations in one variable and use them to solve problems.
G.CO.2 Represent transformations.
Students will understand how levers and fulcrums are used in construction.
Teacher Notes/Materials Needed:
Ruler, cups, fulcrum, fun size candy bars, 2 x 10 x 10,
CTE Situation (opener):
What principle is involved in deciding how far you can cantilever a deck or 2nd floor, or how big a hammer or crow bar is needed to pull a nail? Why is holding a hammer close to the head less efficient than holding it close to the end of the handle?
Lesson Sequence: Can 1 candy bar lift 6 candy bars?
1. Show a visual demonstration of the lever/fulcrum principle by using a ruler, pen (fulcrum), 2 plastic cups, fun size candy bars. Model this with the fulcrum at the center of the ruler with a cup containing 1 candy bar placed on one end of the ruler and a cup containing 6 candy bars on the other end (note it does not balance).
a. Discuss and experiment with ruler lever/fulcrum so that 1 candy lifts 6 candies.
b. An extension, using a 2 X 10 x 10, have a lightweight student lift a larger (football player type) student.
c. Process with students using the photos above, where is the fulcrum and lever located? This is a great place to talk about the “center of rotation” and “translation” of the fulcrum.
2. Transition into developing a math expression/equation to represent the lever scenario
longer distance X lighter person = shorter distance X heavier person
or express as a proportion
Thanks to John Gregory & Steven Davis of Norwich, NY for letting this problem be reprinted.