The Force ofThe Force ofGravityGravity

3.1.2: Participate in different types of guided 3.1.2: Participate in different types of guided scientific investigations, such as observing scientific investigations, such as observing objects and events and collecting specimens objects and events and collecting specimens for analysis. for analysis.

What is Force?What is Force?

Write a sentence in your science journal Write a sentence in your science journal explaining what force is. Support your explaining what force is. Support your sentence by including examples of force, sentence by including examples of force, both inside and outside of the classroom.both inside and outside of the classroom.

The Force of GravityThe Force of Gravity

Gravity is a force that pulls on every Gravity is a force that pulls on every object on Earth. Have you ever wondered object on Earth. Have you ever wondered if the pull is always the same for every if the pull is always the same for every single thing? If you drop a penny and pen single thing? If you drop a penny and pen from the same height, will they hit the from the same height, will they hit the ground the same time? What about a ground the same time? What about a piece of paper and a pen; can you guess piece of paper and a pen; can you guess what will happen?what will happen?

Let’s Test Gravity!!Let’s Test Gravity!!

Materials:Materials: A desk or tableA desk or table A ruler or pencilA ruler or pencil Different sized marblesDifferent sized marbles A binder or books and a small tableA binder or books and a small table

Let’s Test Gravity!!Let’s Test Gravity!!

First make a ramp. You can use a binder First make a ramp. You can use a binder or tilt a small desk by putting books under or tilt a small desk by putting books under two of the legs. Make sure the ramp is two of the legs. Make sure the ramp is tilted just a little bit so the marbles will roll tilted just a little bit so the marbles will roll slowly. The smoother surface, the better!slowly. The smoother surface, the better!

Take two marbles, a big one and a small Take two marbles, a big one and a small one. Line them up evenly at the top of the one. Line them up evenly at the top of the ramp.ramp.

Let’s Test Gravity!!Let’s Test Gravity!!

Use a ruler or meter stick as a gate. Hold the Use a ruler or meter stick as a gate. Hold the starting gate and lift it quickly so that both starting gate and lift it quickly so that both marbles start to roll at the same time. marbles start to roll at the same time.

Watch the finish line closely to see if one Watch the finish line closely to see if one marble comes in first or if it’s a tie. marble comes in first or if it’s a tie.

Do the race 3-4 times to check for accuracy. Do the race 3-4 times to check for accuracy. Does one marble win the race, or is it a tie? Does one marble win the race, or is it a tie?

Are the results the same for every race?Are the results the same for every race?

MORE about Gravity!!MORE about Gravity!!

Have you ever noticed the force of a Have you ever noticed the force of a magnet? If you put two magnets next to magnet? If you put two magnets next to each other, they will either push or pull each other, they will either push or pull on one another. The push or pull is the on one another. The push or pull is the force of magnetism. Gravity is a force force of magnetism. Gravity is a force too, it makes all things attract each other. too, it makes all things attract each other. The bigger the object, the stronger the The bigger the object, the stronger the force is. Try slowly pulling two magnets force is. Try slowly pulling two magnets apart. What do you feel?apart. What do you feel?

Exploring GravityExploring Gravity

In your science journal, write an In your science journal, write an explanation for how gravity is involved in explanation for how gravity is involved in each of the following:each of the following:

Playground slidesPlayground slides SeesawsSeesaws SwingsSwings SledsSleds SkisSkis

Prediction/AssessmentPrediction/Assessment "Common sense suggests that heavy objects are "Common sense suggests that heavy objects are

pulled toward the Earth with greater force than lighter pulled toward the Earth with greater force than lighter objects. That is why they feel "heavier"; they are objects. That is why they feel "heavier"; they are pulling harder against our hands as they try to fall to pulling harder against our hands as they try to fall to Earth. Does this mean that a heavy object will fall Earth. Does this mean that a heavy object will fall faster than a lighter object?"faster than a lighter object?"

Think about this statement and write a prediction in Think about this statement and write a prediction in your science journal, based on your prior experiences. your science journal, based on your prior experiences. How could you figure the outcome after writing your How could you figure the outcome after writing your prediction? How is gravity related to objects feeling prediction? How is gravity related to objects feeling heavier or lighter? (You may look at collected heavier or lighter? (You may look at collected information in your science journal for help)information in your science journal for help)

ExtensionExtension

Visit the Visit the How Things FlyHow Things Fly exhibit at exhibit at

http://www.nasm.si.edu/exhibitions/gal109/http://www.nasm.si.edu/exhibitions/gal109/NEWHTF/HTF030.HTMNEWHTF/HTF030.HTM

Look, Play, & Learn!!!!Look, Play, & Learn!!!!