Simple MachinesSimple Machines

Activity Two: Levers Move the Activity Two: Levers Move the WorldWorld

Essential QuestionsEssential Questions

How does a lever make moving something How does a lever make moving something easier?easier?

Where should you hold a lever to Where should you hold a lever to maximize its effectiveness?maximize its effectiveness?

GoalsGoals

Identify the effort force, the fulcrum, and Identify the effort force, the fulcrum, and the resistance force in a simple lever the resistance force in a simple lever system. system.

Investigate the effect of lengthening the Investigate the effect of lengthening the effort arm on the effort force and the effort arm on the effort force and the mechanical advantage of a lever system.mechanical advantage of a lever system.

Investigate the effort force & effort Investigate the effort force & effort distance relationship. distance relationship.

Main IdeasMain Ideas

As the effort arm increases (the length As the effort arm increases (the length from the fulcrum to the effort force), the from the fulcrum to the effort force), the effort force decreases. Consequently the effort force decreases. Consequently the distance traveled by the effort force in distance traveled by the effort force in completing the task is increased. completing the task is increased.

An inverse relationship exists between the An inverse relationship exists between the effort force and the effort distance.effort force and the effort distance.

Main Ideas Cont.Main Ideas Cont.

The size of the effort force, the resistance The size of the effort force, the resistance force, and the fulcrum affects the force, and the fulcrum affects the effectiveness of the lever system and its effectiveness of the lever system and its ability to accomplish a task. ability to accomplish a task.

VocabularyVocabulary

Resistance Force (load): is the Resistance Force (load): is the forceforce which an effort which an effort forceforce must overcome in must overcome in order to do work on an object order to do work on an object

Effort Force: the Effort Force: the forceforce used to move an used to move an object over a distance object over a distance

Effort Distance: the Effort Distance: the distancedistance from the from the efforteffort (on a lever) to the fulcrum (on a lever) to the fulcrum

Vocabulary Cont.Vocabulary Cont.

Lever: a simple machine that makes work Lever: a simple machine that makes work easier for use; it involves moving a load easier for use; it involves moving a load around a pivot using a force around a pivot using a force

Fulcrum: the support about which a lever Fulcrum: the support about which a lever turns turns

What do I do?What do I do?

Read Activity 2Read Activity 2Do Part A: Getting a Feel for LeversDo Part A: Getting a Feel for LeversWrite observations in your journalWrite observations in your journalDo Part BDo Part BWhat is a spring scale and how do I use it?What is a spring scale and how do I use it?Do Part CDo Part CDo Part DDo Part DInvestigation ReflectionInvestigation ReflectionRead Investigation FurtherRead Investigation FurtherSummary of the ActivitySummary of the ActivityApplying What You Have LearnedApplying What You Have Learned

Essential QuestionsEssential Questions

Go back and answer your essential Go back and answer your essential questions!!!questions!!!

How does a lever make moving something How does a lever make moving something easier?easier?

Where should you hold a lever to Where should you hold a lever to maximize its effectiveness?maximize its effectiveness?