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Newton's First Law of Motion | PBS LearningMedia

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Find out about Newton's First Law of Motion, plus a little bit of baseball, with this animation.

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Using the Interactive

The Roller Coaster Model Interactive is shown in the iFrame below. There is a small hot-spot in the lower-right corner of the iFrame. Dragging this hot-spot allows you to change the size of iFrame to whatever dimensions you prefer.

Using the Interactive

This Interactive will open in a separate browser window on your device. Click the Launch Tool button to open the Interactive. Close the window to return to this page.

Our Roller Coaster Model simulation is now available with a Concept Checker. Do the simulation. Then follow it up with the Concept Checker.

Our Roller Coaster Model simulation is now available with a Concept Checker. Do the simulation. Then follow it up with the Concept Checker.

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Physics Simulation: Roller Coaster Model

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Design a track. Create a loop. Assemble a collection of hills. Add or remove friction. And let the car roll along the track and study the effects of track design upon the rider speed, acceleration (magnitude and direction), and energy forms.

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If you did not finish your notes for Describing Motion in class, you can find the reading here.

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Water Jetpack - watch the first two minutes

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Water Jetpack - watch the first two minutes

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Awesome Water Jetpack - Compilation 2015

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Balloon Rocket! Newton's Third Law of Motion.

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Boats and boating--Equipment and supplies

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Change variables and observe how the ball moves through the air

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Answer questions and make your way around a maze

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Wordwall - Create better lessons quicker

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1) A push or pull is a what? a) Gravity b) Force c) Inertia 2) A force that pulls all things towards Earth a) Gravity b) Force c) Inertia 3) We consider an object to be in ______________ when it is not standing still. a) Force b) Gravity c) Motion 4) For an object to move a ___________ must be applied. a) Force b) Gravity c) Motion 5) Is a PRESS a push or pull? a) Push b) Pull 6) Is a TOW a push or pull? a) Push b) Pull 7) Is a THORW a push or pull? a) Push b) Pull 8) Is a YANK a push or pull? a) Push b) Pull 9) Is a STOMP a push or pull? a) Push b) Pull 10) If a sheep is sitting on the roof of a car and the car hits a wall, what happens to the sheep? a) It stays where it is. b) It will stand up and dance. c) It will fly off the car. 11) Why would a sheep fly off a car if it is not buckled in and it hits a wall? a) The force will knock it off if it isn't secured b) The gravity will keep it down in the seat. c) Inertia slows the car down and the sheep won't move. 12) Which surface would a ball roll farthest on? a) Smooth Metal b) Smooth Wood c) Rough Sandpaper 13) Which surface would a ball roll the least distance on? a) Smooth Metal b) Smooth Wood c) Rough Sandpaper

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1) A push or pull is a what? a) Gravity b) Force c) Inertia 2) A force that pulls all things towards Earth a) Gravity b) Force c) Inertia 3) We consider an object to be in ______________ when it is not standing still.

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STEMonstrations: Newton's First Law of Motion

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Science of NFL Football: Newton's First Law

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Science of NFL Football: Newton's First Law

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Newton's First Law of Motion   Science of NFL Football

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Science of NFL Football: Newton's Third Law

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Science of NFL Football: Newton's Third Law

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Newton's Third Law of Motion 🏈 [Science of NFL Football]

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From NASA

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STEMonstrations: Newton's Third Law of Motion

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A more expert level text, from Wired magazine

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You might have noticed that I'm not too fond of the way some textbooks (and shows) word Newton's third law. In fact, I think students get too focused on THE THREE LAWS instead of just modeling force and motion.

The problem with this law is when it is described in the following way:

Newton's Third Law: For every action, there is an equal and opposite reaction.

Not all textbooks say that, but if you ask a random person on the street that is likely what they will describe as Newton's third law.

The Best Version of Newton's Third Law

Here's my short version.

Forces come in pairs. Forces are an interaction between two objects. This means that if object A pushes on object B, then object B pushes on A with the same force but in the opposite direction.

My favorite analogy is with distances. Distances are between two points. The distance from A to B is equal but opposite the distance from B to A. See. It's simple.

What's Wrong With the Other Version?

There isn't anything exactly wrong with the "action and reaction" version of this part of force? First, no disrespect to Frank's Action-Reaction blog - it's quite excellent. However, when you put the words "action" and "reaction" in a description of forces most people will think about movement. In fact, you might even see something like this in an example of Newton's Third Law:

A person steps off a boat. As the person moves to the left, the boat moves back to the right. Action. Reaction. Are there equal and opposite forces acting on the person and the boat? Yes. However, it doesn't mean that both have to move. Action implies motion (at least it does for me). Also, if the boat is much more massive than the person then it won't recoil as much as the person moves. This might lead someone to believe that the action and reaction don't have to be the same. To be honest, I'm not sure they do have to be the same. I'm not sure if there is a formal definition of action and reaction.

What about a Newton's Third Law example where things don't move? Consider the following situation.

The person is in equilibrium because there are two forces acting on the person. The gravitational force from the Earth pulls down and the ground pushes up on the person. The "equal and opposite" forces in this example are the two gravitational forces. The person pulls on the Earth with the same force the Earth pulls on the person. Equal and opposite even though neither has to be moving.

What about the force the ground exerts on the person? Yes, it's true that this force has the same magnitude but opposite direction as the gravitational force due to the Earth. However, it isn't the same force. It just happens to be equal. Force pairs are an interaction between objects. This means that the two paired up forces also have to be acting on two separate objects.

Looking at the Source of Action and Reaction

Let me make something clear. Isaac Newton had it tough. Here he is trying to make a model that describes what forces do to objects. However, he just doesn't have all the words we have - like momentum, acceleration, velocity.

Fortunately, there is an online translation of the original works of Newton. Here is an older translation into English of Newton's The Mathematical Principles of Natural Philosophy (volume 1).

The part about the Third Law says:

To every action there is always opposed an equal reaction: or the mutual actions of two bodies upon each other are always equal, and directed to contrary parts.

He also writes:

If you press a stone with your finger, the finger is also pressed by the stone.

This above example could indicate that he did not mean the stone and the finger have to move. I would suggest that perhaps Newton meant the word "action" to really mean "force". However, he later uses the word force so I'm not exactly sure of his intentions. Perhaps by "action" he means a force that actually does something. I don't know.

Oh, and it seems Newton does use the words momentum and velocity (if you read more of the passage). Maybe he was just trying to be poetic with his use of the words "action" and "reaction".

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You might have noticed that I'm not too fond of the way some textbooks (and shows) word Newton's third law. In fact, I think students get too focused on THE THREE LAWS instead of just modeling force and motion. The problem with this law is when it is described in the following way: Newton's Third [...]

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Newton's Second Bit of Advice for All of Us

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Newton's Second Bit of Advice for All of Us

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Newton's Second Bit of Advice for All of Us

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video from PBS

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Accelerating Mass: F=ma | PBS LearningMedia

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In this animated video, students learn about mass: the measure of an object's ability to resist being accelerated by a force.

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From the Royal Observatory Greenwich

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Join our Royal Observatory Greenwich astronomers as they go on an epic journey to find out how Newton's Laws of Motion work in space.  Buckle your seatbelts, you are in for an adventure. http://www.rmg.co.uk/plan-your-visit/schools/royal-observatory #ROGschools

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Newton's 3 Laws, with a bicycle - Joshua Manley

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A more expert text

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Science of NFL Football

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Newton's Second Law of Motion 🏈 [Science of NFL Football]

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STEMonstrations: Newton's 2nd Law of Motion