Science project on gravity & motion for third graders

Written by tamara christine van hooser Google
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Science project on gravity & motion for third graders
A rocket launch provides an exciting demonstration of reaction forces. (fun space rocket image by Leslie Batchelder from

A science project on gravity and motion for third graders introduces students to Newton's three laws of motion. The scientific process teaches third graders both scientific principles, and observation and data collection skills.


Georgia Louviere of Rice University simply explains that mass equals weight, acceleration equals speed and the reaction force is the strength with which an object pushes back when it collides with another object. Janice VanCleave defines gravity as "a force that pulls things down toward Earth's surface."

First Law: Inertia

The first law of inertia states that an object at rest tends to stay at rest unless acted on by an outside force.


To demonstrate inertia, a student can try Rice University's "Egg Drop." An egg resting on a tube placed on cardboard above a bowl of water should drop into the bowl when the cardboard is quickly removed.

Second Law: F=MxA

The second law defines that it takes more force to move a heavier object than a lighter object the same distance.


Home Training Tools suggests illustrating acceleration forces by "dropping a rock or marble and a wadded-up piece of paper at the same time" from the same height into a dish of sand or flour. The craters' sizes show the force of impact. Compare the craters to find out which object has greater force and why.

Third Law: Reaction Force

The third law says that for every action there is an equal and opposite reaction.


Third graders can discover reaction force by examining why a water cup spins clockwise in the opposite direction of the water force released from the straws in its' side with Janice Van Cleave's "Hero's Engine."


The Exploratorium explains that an object's centre of gravity is the place where it will balance on a single point. See Resources to locate the centre of gravity on a long , thin object.

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