Home's Cool Learning Activity: Gravity Demo

https://www.youtube.com/watch?v=ZFxThjSZjmU&feature=emb_logo Home's Cool! While we're all working from home, the parents, former teachers, and play experts at EI are sharing some of their favorite educational activities to help keep your family learning and growing. Check out this idea from Michael Sheridan, one of our Product Managers!Ages: 4-12Grades: pre-K-6Supplies:• Cardboard box• 2 Similar-sized objects• Camera or phone with slow-motion video capabilitiesProcedure:1. Stand a cardboard box on end, with the open flaps facing you.2. Set up your slow-motion camera to record the objects falling.3. Using one hand to support the flap, place both objects on one flap of the cardboard box and make sure they are not moving.4. Start recording on the slow-motion camera.5. Drop the flap on the cardboard box.6. Watch the video of the objects falling. Are they falling at the same speed? Or is one object falling faster than the other? Try dropping other objects! Do you notice any relationship between the shape and how the object falls? How about the size? Or weight?Explanation:The force of gravity is all around us. We experience it every day on Earth, whether or not we think about it. Sir Isaac Newton was the first to develop a mathematical explanation for gravity, which includes the importance of mass and distance. If an object has a lot of mass (is very heavy) then it will impose a larger gravitational force than other, smaller objects experience.When we drop two objects like the ping pong ball and tangerine in the video, they fall to the ground because the force of gravity is pulling them toward the center of the Earth. This gravitational force applies to everything on Earth, from an apple growing on a tree to a car parked on the street, and even planes in the sky.Now it’s time to experiment with dropping different objects! Be sure you aren’t dropping anything that might break. As mentioned in the video, this experiment is ignoring the effects of air resistance. Since we are in our homes and not a science lab, we can see how gravity affects all objects, but we can also see how the shape of an object changes the air resistance it feels as it falls to the ground.For this experiment, we are focusing on Newton’s Second Law, or F = ma.This law says the force an object feels (in this case, the force of gravity from Earth) equals the mass of that object (how heavy it is) multiplied by the acceleration it experiences. Everything on Earth feels the same acceleration toward the center of the Earth.So, what happens if we drop a ping pong ball and a baseball? A baseball weighs about 145 grams but a ping pong ball weighs about 3 grams. The acceleration is the same since both objects are on Earth, so the force the baseball feels is about 50 times as large as the force the ping pong ball feels (because it weighs almost 50 times as much).Why does it look like they reach the ground at the same time? The reason is inertia. Inertia is resistance to acceleration and depends on how much something weighs. If something weighs more, it won’t accelerate as fast. That’s why the ping pong ball starts to fall faster than the baseball.If we repeat this experiment with different-shaped objects, we can see the effects of air resistance. Try this out a piece of paper and a ball. The ball is round so the air can move around it easily, but the paper is a large rectangle, making it difficult for the air to go around it. The air resistance slows down the acceleration of the paper toward the ground, which is why it moves back and forth and reaches the ground after the ball.EI Product Manager Michael Sheridan is a jack of all trades! An avid surfer and former international soccer competitor, this outdoor and sporting enthusiast also has a degree in Astrophysics from UCLA and eight years of product development experience in a variety of industries. Prior to helping build EI's science products and brain game lines, Michael developed everything from folding chairs to electric scooters and skateboards!