Inertia & Gravity

We finished up our forces of motion experiments today, here are some of our other experiments:

Inertia
Objects at rest want to stay at rest, objects in motion want to stay in motion unless another force changes their mind.  (That's me paraphrasing Newton....)

The good old fashioned pull out the paper trick!  We did several variations, including the coin on the top of the glass and a full glass of water.

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Another demonstration (no photographs for lack of junior scientists choosing to repeat) is to bounce a ball on a hard surface and then on a soft surface  (like a folded up quilt or blanket) from the same height and with the same force.  This demonstrates the acting of an outside force.

If you happen to have Netflix, there are several episodes of MythBusters that deal with inertia.  The kids favorite is Tablecloth Chaos where they try to overcome and adjust the various forces to do the tablecloth trick on a long banquet table.  I big time recommend it...especially if you happen to present a lesson on inertia on the same day that the baby and two other smallish children all got up at 5 AM and are in need of a nap.

Gravity
Not gonna paraphrase this one for you...I think you can handle your own definition.

Gravity is fun.  Just drop a bunch of stuff!  A cork and a rock are a good comparison and then exchange the cork for a piece of paper.  Then crumple up the paper into a ball and observe again.


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We add a conversation about what gravity looks like on the other side of Earth.  If we are pulled down are people pulled away from Earth there?  What about on the side of a mountain, are we pulled down toward the ground?   Lucie helps by sitting on the table holding onto the Earth for us.....

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Eventually with some conversation and discovery, they come up with a definition of gravity pulling us towards the center of the Earth.   It helps to have a plumb line and a level at this point.  Or if you don't have a plumb line, tie a screw to the end of a piece of string....that's what I did.

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