For Kids

Science Experiment: Newton's Second Law of Motion


Sir Isaac Newton was an English scientist. He was born in 1642 and died in 1727. This was around the time of the early colonization of North America: the founding of some of the original 13 colonies, the French and Indiana wars and the Salem witch trials, but before the American Revolution.

Newton is best known for three very important principles of physics called classical mechanics. These principles describe how things move and are referred to today by his name - Newton's Laws of Motion. There are three of them, Newtons First, Second and Third Law of Motion. Today's experiment will demonstrate Newton's Second Law of Motion.

Newton's Second Law of Motion states that acceleration is produced when a force acts on a mass. Riding your bicycle is a good example of this law of motion at work. When you push on Bicyclethe pedals of your bicycle, your bicycle moves, or accelerates. You are increasing the acceleration of the bicycle by applying force to the pedals. Your leg muscles pushing on the pedals is the force that is making the bike move.

Newton's Second Law also states that the greater the mass (of the object being accelerated) the greater the amount of force needed (to accelerate the object). Say you have two identical bicycles that each have a basket. One bicycle has an empty basket. One bicycle has a basket full of bricks. If you try to ride each bicycle and you push on the pedals with the exact same strength, you will be able to accelerate the bike with the empty basket MORE than the bike with the basket full of bricks. The bricks add mass to the second bicycle. With bricks in the basket, you would have to apply more force to the pedals to make your bicycle move.

Comet Cratering Demonstration

TryScience Comet Crateringsrpcometsetup2


We gathered the items suggested by TryScience and gave this one a try. We put several spoonfuls of flour in the bottom of a pie plate and spread it out to make a level surface. Then we sprinkled a thin layer of hot chocolate mix on top of the flour. We held a marble above the pie plate and dropped it. The marbles made perfect sphere imprints in the flour.

Comet Cratering Science Project:

Use three different sizes of marbles to turn this demonstration into an experiment. Remember that in a science experiment you want to test only ONE variable. In this experiment you only want to change the size/weight of the object that is falling. You want to make sure each object is the same shape. The marbles are all spheres. They are all the same shape. If we changed the shape of the object too, it would be hard to measure the difference in the impact craters. You also need to pay close attention to how far away the marbles are from the surface of the flour before you let go of them. Use a ruler to make sure you drop each marble from exactly one foot above the surface of the flour. The shape of the objects and the distance the objects are away from the surface are the SAME. Only the size of the objects are different.

Do the experiment three times using the same three marbles that are the same shape and dropped from the same height, but are different in size. The three times you repeat the experiment are called trials. Make a chart to keep track of the results. After each trial measure the width of the impact crater made by each of the three marbles. Which marble makes the largest impact crater? Which marble makes the deepest impact crater? Why do you think so?

Websites, Activities & Printables:

Science in Context
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Junk Drawer ScienceScience Stunts Fun Feats of PhysicsWho Was Isaac Newton?Lives of the ScientistsWhat Are Newton's Laws of Motion?Can You Feel the Force?Give It a Push Give It a PullIsaac Newton Discoverer of GravityGiants of Science Isaac NewtonIsaac the AlchemistPhysics Investigate the Mechanics of NatureProfessor Astrocat's Atomic Adventure a Journey Through PhysicsYou Wouldn't Want to be Sir Isaac NewtonIsaac Newton and Physics for Kids

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