ISAAC NEWTON’S THREE LAWS OF MOTION Tahoma Jr. High Maple Valley, WA

Newton studied many different aspects of Nature – such as when he used a prism to separate white light into the rainbow spectrum of colors (we’ll do the same when we study light). Newton lived from 1642 to 1727.

You have probably also heard the common story that Newton “discovered” gravity when he was hit on the head with an apple. NOT true… (another example of where you need to be careful of “history” and how stories get exaggerated over time)

The true story is that he grew up on a farm and watched lots of apples falling - which started him thinking about how Nature’s forces controlled all moving objects, leading to his interest in Astronomy… and trying to figure out the Moon and Sun’s movements.

To solve those types of problems, he actually invented a new branch of mathematics… CALCULUS !! However – history here is not totally accurate either, Newton “stole” the credit for this from a man who, at the same time, created a better version of calculus. His name was Leibniz. Ever hear of HIM ??!

So after Newton described this force called “gravity” that affects the motion of objects, he looked at those objects closer and came up with Three Laws that control their movement. And it’s actually easier to learn those laws by simply looking at an object instead of memorizing a list of three things!

Newton’s 1 st Law: Just look at an object, and whatever it is doing now, it’ll continue doing (unless some other force acts on it)

Newton’s 2 nd Law: That moving object you’re looking at (in the 1 st Law) has Force behind it – which depends on how big it is and how fast it’s moving !

Newton’s 3 rd Law: Then, if that object hits something else, there will be an equal and opposite Force to the Force that object has from the 2 nd Law. Newton’s Cradle Why science teachers should not be assigned playground duty.

Examples of Newton’s 1 st Law (The Law of Inertia) are: Why you can yank a tablecloth out from under dishes. Why spacecraft (like the Voyagers and Pioneers) can travel such long distances by “coasting” without their engines on.

An example of Newton’s 2 nd Law (Momentum) says that Force depends on mass and velocity: A small object moving very quickly can have the same force as… a large object moving very slowly. F = m x a

Examples of Newton’s 3 rd Law (for every action there is an equal and opposite reaction) are: Try this one next time you’re around a skateboard and a heavy ball.

Take a look at all the places that Newton’s Laws are working in your everyday life. Just like with friction, and simple machines, they are happening everywhere. end show