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Newton’s Law
Demonstrations
http://science360.gov/obj/video/70fadaa8-c3d4-4132-ba1fc98be5caeb14/science-nfl-football-newtons-first-law-motion
Vocabulary Review
• Motion – a change in position
• Inertia- the tendency of an object to resist a change in its motion.
Objects with more mass have more inertia
• Force- a push or a pull
• Balanced forces- cancel each other out, no motion occurs
• Unbalanced forces- don’t cancel each other out and motion occurs
• Newton’s 1st Law of Motion- an object at rest tends to stay at rest
and an object in motion tends to stay in motion unless acted on by
another force.
• Friction- a force that acts to resist motion between two touching
objects
Magic Table Cloth
• Place the funnel upside down on top of the
blue paper.
• Quickly remove the blue paper (pulling
down and away helps!)
• Observe the motion of the funnel.
• What’s Going On?
• Initially all objects are at rest. When an
outside force (your hands) acts to remove
the paper, it does not act on the funnel.
Therefore, the funnel remains at rest on the
top of the table.
Drop the Domino
• Place the card on top of the beaker.
• Place the domino (or 2) on top of the card.
• Quickly flick the card out from underneath the domino.
• Observe the motion of the domino.
• What’s Going On?
• Initially all objects are at rest. When an outside force (your finger)
acts to move the card, it does not act on the beaker or domino.
Therefore, they remain at rest. The domino does experience vertical
motion due to gravity and drops into the beaker.
Ball in the Box
• Place the ball in the empty box.
• Slowly push the box.
• Abruptly stop the box.
• Observe the motion of the ball.
• What’s Going On?
• According to Newton’s First Law, an object in motion tends to stay in
motion unless acted upon by an unbalanced outside force, so the ball
keeps rolling even though the box stopped.
Whirlpool
• Fill the beaker halfway with water.
• Swirl the beaker until you have made a whirlpool.
• Quickly stop the beaker.
• Observe the motion of the water. Does it stop too?
• What’s Going On?
• Inertia causes the water, which was in motion, to remain in motion. It
doesn’t stop right away when you stop twisting the beaker.
Short Stack
• Stack the dominos in a tower.
• Use the ruler to hit the domino on the bottom of
the tower with a swiping motion.
• Observe the motion of the domino stack.
• What’s Going On?
• The domino being hit is now in motion, it will stay in motion until air and
the table stops its motion.
• The stack is at rest. It will stay at rest and should remain standing. The
downward movement is caused by gravity.
Inertia Blocks
• Find the two blocks and lift them one at time in
your hands.
• Are they the same? Are you using the same
amount of force to lift them?
• Why is one harder to move?
• What’s Going On?
• Objects with more mass have more inertia (resistance to moving or
stopping movement).
Friction Slide
• Set up the ruler like a ramp.
• Give a gentle push and slide a block
down the ramp.
• How could you slow down the sliding block?
• What’s Going On?
• To increase friction, you can change the texture of the surface and make
the surface rougher (add sandpaper for example). This will slow the
motion of the blocks.
Tug of War
• Two people sitting across from each other
should each take a spring scale and hook the
hook onto one of the binder clip loops.
• Slowly and carefully, pull the spring scales apart
until the binder clip starts to open, then hold it.
• Read the amount of force (in Newtons) on the spring scales being used to
pull on the binder clip.
• Is this a balanced or unbalanced force? Will it result in motion or no motion?
• What’s Going On?
• Equal amounts of force should be used in this tug of war. This is a balanced
force and will result in no motion.
A Challenge
• Can you use inertia to perform the
magic tablecloth trick with a larger set
up?
• ASK FOR YOUR PARENT’S PERMISSION
BEFORE YOU BEGIN AND PRACTICE
WITH PLASTIC FIRST!!!
• http://www.youtube.com/watch?v=PcG
IUZzWoVc
• Email a video of your performance!
What did I learn?
• Write your name at the top of the paper.
• Complete an exit slip stating in at least three sentences what
you now know about :
• Forces (balanced and/or unbalanced)
• Friction
• Inertia
• Newton’s 1st Law of Motion