Lauren
Dark & Ashleigh Taylor's Science Team.
DAY ONE:
On our first visit to Mrs.
Dark's class at Dadeville Elementary School, we taught her
second grade class about force and inertia with the following
experiments.
Force:
1) Fist and fingers- One person holds their first
together tightly on top of each other while a second person
uses their two index fingers to hit the fist sideways and
separate them.
-How does
this work? Vertical forces and horizontal forces are
independent of each other. The only help you have to keep your
fist together is a small friction force.
2) Dollar drop- We split the children into groups
to two. One child would extend one hand and rest it on a desk.
Then other would hold a dollar vertically at the top. The
catcher position his or her fingers on either side of George
Washington's face, as close as he or she wants with out
touching the bill. Then when the bill is released they try to
catch the dollar.
-Why is this impossible? The gravitational force on the dollar causes it to
speed up instantly, outrunning the person's reflexes.
They had so much fun, we gave them a reflex reaction test
to take home
Inertia:
1) Marbles and rice- Place a marble in the bottom
of a glass and fill the glass with rice. Rest the glass on
one's hand and apply a sharp downward taps to the top rim of
the glass with the other hand. The marble will rise to the
top.
-How does this
work? Inertia of the marble is greater than the individual
grains of rice. The taps deliver enough force to cause the
rice to fall, but not the marble. So it actually does not
move. The rice just falls out from underneath it.
2) Card and Quarter-
Place a quarter on a card, and the card on your middle finger
being careful to place the quarter directly above the finger.
with the other hand try to flick the card out from under the
quarter.
-How does the quarter stay? Objects have inertia
and resist motion unless a force is applied. The force
down caused by gravity is much greater than the small
friction force pushing the object sideways.
