1. Why does a penguin slide further than a polar bear?

Do Now

Do now

1. Why do you think a penguin slides/rolls further than a bear?

Announcements

Tests Cougar Time tomorrow Field trip on Wednesday Awesome lab on Thursday Lab stations on Friday

Newton’s Laws

Newton’s Laws are all about force and motion.

Force is a push or pull

Types of force

Contact force: when on object pushes/pulls another object

Gravity: Force of attraction between two masses.

Friction: Force that resists motion between two surfaces.

Balanced and unbalanced forces

Overall force acting on an object when forces are combined is the net force.

If the net force on an object is zero, the forces acting on the object are balanced.

Unbalanced force can change the motion of an object.

Sir Isaac Newton

Born on December 25th, 1642 and died March 20th, 1727.

Considered to be one (if not the) greatest and most influential scientist who ever lived.

Checking for Understanding

What is force? What is an unbalanced force?

What’s so great about him?

Wrote a book about classical mechanics.

Described universal gravitation Three laws of motion.

Why’s he important to us as 7th graders?

We are studying motion currently and are beginning to learn about his three laws.

Newton’s 1st Law

Newton’s 1st Law: An object at rest will remain at rest and an object in motion will remain in motion unless an unbalanced force acts upon it.

Newton’s 1st Law

Anytime you read about a situation where something is at rest and then it starts moving or is moving and then it stops, it is talking about Newton’s 1st Law.

Newton’s 1st Law

There is a box that is sitting on the floor at rest. It will remain at rest until somebody pushes it.

At rest… In motion…

Checking for Understanding

What does Newton’s first law state?

Newton’s 1st Law

You are driving in a car with no seat belt on. You see a family of ducks and slam on your brakes to avoid hitting them. Since you are not wearing your seat belt, you fly out of the car (remain in motion) until you hit the ground (an unbalanced force).

AHH!

Ouch

In motion… At rest…

Inertia (ih-NER-shuh)

Inertia is the resistance of an object to a change in the speed or direction of its motion.

How does this apply to Newton’s 1st law? The first law describes the tendency of

objects to resist changes in motion. AKA they’re one in the same.

Graphic organizer

I’m passing out a graphic organizer that YOU MUST NOT LOSE!

We’ll be using this for all of Newton’s three laws.

When you get the organizer, go ahead and write in what Newton’s first law states.