Explaining Newton's first law

[toomuch]

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I am currently involved in participating in many different outreach activities for elemeantary to high school age kids.

Our demonstration of Newton's 1st law has been a big hit and I wanted to share it with other SDNers that might be involved in similiar activiities.

Newton's first law: An object at rest tends to stay at rest and an object in motion tends to stay in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

Materials: Queen size mattress and skateboard

The demonstrator rides his skateboard until he hits the mattress.
The skateboard stops, but the skateboarder is still moving forward onto the mattress.

The kids loved it and continued to ask for repeat demonstrations.

I thought it was great.

tm

 

[logos]

I am currently involved in participating in many different outreach activities for elemeantary to high school age kids.

Thats awesome...doing science demos for elementary school kids would be a blast.

 

[Irene Adler]

I'm a middle school science teacher--there's a quicker demo that is also impressive:

Take a strip of paper, about 1 inch by 10 inches. Have about 2 inches resting on the edge of a table, with the rest hanging over the end. Take a highlighter marker, and place it, end up, on the part of the paper that is on the table. Challenge the students to remove the paper from underneath the highlighter without touching or moving the highlighter.

When it is your turn, gently grasp the hanging end from the tip and hold it taut. With your other hand, 'karate chop' the middle portion of the paper. The highlighter doesn't move.

Alternatively, set a table with heavy (strong) dishware and a thin, smooth cloth tablecloth. Grasp the hanging edge of the tablecloth with both hands. Pull down quickly and sharply. If you are fast enough, and the dishware is heavy enough without there being too much friction, the dishes will remain in place. Then suggest that your students try it at home with their mother's best china.

"An object at rest tends to stay at rest, and an object in motion at constant velocity tends to stay in motion at constant velocity unless acted upon by an outside, unbalanced force."

My favorite way to explain inertia: the tendency of an object to resist change in its motion: When my students are reluctant or unmotivated, and the class is not progressing, I threaten to overcome their mental inertia because I am an 'unbalanced' force.