Group Station

1. Correct the brainpop2. Do the inquiry activity3. Work on the HW questions on the back– Use the power point to help you answer these

questions!

Independent Station Directions1. Make flashcards for the following terms. • Lever• Fulcrum• Resistance/Load• Effort• Mechanical Advantage• 1st class lever (definition comes at the beginning of the slide)• 2nd class lever (Definition comes at the beginning of the slide)• 3rd class lever (definition comes at the beginning of the slide)2. Choose any 10 flash card words and use them in a

complete sentence on a blank piece of paper. DO NOT JUST WRITE THE DEFINITION

3. Practice the flash cards with a neighbor or independently.

Wednesday, March 13th, 2013 Your Learning Goal:

Students will be able to identify and classify different levers in the body and explain lever’s advantage.

Standard: 5c: Students know how bones and muscles work together to provide structural framework for movement.6h: Students know how to compare joints in the body with structures used in machines and simple devices

Table of Contents: 6.8 Levers in the bodyHomework:Due: 3/19

6.8 Lever Inquiry6.8 Flash Cards

Agenda:1. Do-Now2. Stations

Do Now

Table of Contents:# Title date page6.6 Musculoskeletal Quiz 3/12 11-126.7 Joints 3/13 13-16

3/146.8 Levers In the Body 3/17 17-20

What is the musculoskeletal movement like?

• Muscles and bones work together as A Lever system: Notes tomorrow!

Levers• A rigid bar

that is free to pivot, or move about, a fixed point.

• First the meh• Second the best• Third the worst

What is a lever• A Lever is rigid bar that pivots at a fixed point • A Fulcrum is the fixed point that a liver pivots at• The effort is the force you put on the lever: Can be up or

down• The resistance/load is the object you are picking up with

your lever

Effort

Fulcrum

Resistance

Mechanical A• Mechanical Advantage is how many times the force

is multiplied in a lever.• Mechanical Advantage: you use less force (effort) to

lift the load than without the lever• This happens when the effort is further from the

fulcrum than the load is from the fulcrum• Mechanical disadvantage happens when the load is

further from the fulcrum than the effort is from the fulcrum.

Mechanical Advantage

What is Mechanical Advantage

Effort Distance ÷ Load Distance

The effort distance from the fulcrum must be greater than the load distance for their to be mechanical advantage

What is a First Class Lever: Medium Lever

Load

Fulcrum is between the effort and load.• Mechanical advantage only if the effort is further away

than the load• If there is no mechanical advantage, this lever system

only serves to change the direction of motion

Effort

Fulcrum

1st class LeverMedium Lever

Musculoskeletal Levers - 1st Class• Advantage: changes the direction of movement:–Moving your head up and down!!

EffortResistance

Musculoskeletal Levers - 1st ClassTriceps:– The effort is closer

than the load. – Mechanical

disadvantage– Increases the

distance the load moves!

shoulder

EffortFulcrum

Resistance

Second Class Lever: Best Lever

Effort

Fulcrum

Second Class Lever: Best leverThe resistance is between the effort and fulcrum.

• This means the effort is always further from the fulcrum = Always a mechanical advantage

• Use less force to lift a heavy weight

Resistance

Musculoskeletal Levers - 2nd Class• The action of the calf

is a second class lever when jumping or doing toe raises.

• The body weight is in between the effort (calf muscle) and the fulcrum (toes)

fulcrum

Body weight is the resistance.

Effort force is from the calf muscle on the heal.

Third Class Lever: Hardest Lever

Resistance

Effort

Fulcrum

Third Class Lever:Hardest Lever

Effort is between the load and fulcrum: The load is always further = mechanical disadvantage

The lever moves the load a greater distance at a greater speed, but requires a greater force

Musculoskeletal Levers - 3rd Class

FM

R

• Bicep Curls• The bicep pulls on the arm

between the load and the fulcrum: Mechanical disadvantage

• The Speed of the ball increases.

• The distance the ball moves increases

fulcrum

Effort

Resistance

Fulcrum

To summarize