BACKGROUND:
A lever can help move heavy
objects by using weight effectively. A see-saw is a lever that helps you
pick up another person of the same or greater weight.
A wheel and axle
work together to make objects move easily. A car, bicycle, and
motorcycle all use wheels and axles.
A gear helps distribute energy and
moves objects. Many machines such as cars, lawn mowers, and bicycles
have gears. Students will be most familiar with the gears on a bike.
A
pulley helps lift and move difficult objects. Examples include two
pulleys on a clothes-line or big cranes that lift large objects. A wedge
helps to concentrate energy. If a logger wants to cut a log, an axe is
used.
PROCEDURE:
- Discuss different machines that
use simple machines. Students have learned some basic words to help them
describe how a simple machine works. Go over the vocabulary list and
show or discuss examples of each of the simple machines.
- In your module is a nutcracker
(lever), an apple peeler (lever), and an egg slicer (lever and wedge)
add and egg beater (wheel and axle plus
gear). Show each of the machines to the students and slowly go over the
function of each of the machines. In this exercise the students should
look at several ways that these mechanisms work.
- This activity works best if you
have adults at each area demonstrating the different simple machines.
Have the students examine and experiment with each machine except for
the apple peeler.
Station 1. APPLE PEELER. Have
the children guess what is going to happen to the apple when the apple
peeler is used. Go over the parts of the apple (skin, core, meat) as you
cut the apple skin away from the meat. The apple peeler is used as a
lever to cut the apple. The blade however, is shaped as a wedge. Give
each child a sample of the apple to test.
Station 2. NUTCRACKER. Have
the children try and figure out how the nutcracker works. You may want
to demonstrate if they are frustrated. Let them eat the nuts as a reward
for learning that the nutcracker is a lever.
Station 3.
EGGBEATER. Have the
children try and make the eggbeater work in a tub of soap water.
Emphasize that they are using gears to make the eggbeater move. Students
love this activity, so prepare for a mess!
Station 4. EGG SLICER. Have the
children make a ball with the modeling compound and place in the egg
slicer and try to cut the modeling compound.
