Measurement, and Spatial Sense
Space, and Physical Environment
Matter, and Energy
Introduction and Overview
|The purpose of this unit
is to provide opportunity to explore simple machines. Emphasis is
placed on the purposes of simple machines. Students will be able
to apply what they learn to their every day life
||Gravity is a pulling force
between one object and another. The more the matter, the bigger the
pull. Some collapsed stars have very strong gravitational pulls.
Their pull is so strong that nothing can escape them, not even light.
Scientists call these stars black holes. Anything that gets too near black
hole will be sucked in.
||Force means anything that
pushes and pulls. Everything around you is pushing or pulling, and
being pushed and pulled. Whenever you push on something, it pushes
back. When you increase the distance of movement you use less force.
This is Newton's Third Law of Motion.
||Friction happens when two
surfaces come in contact with each other. Without frictional book
would slip out of your hands no matter how tightly you tried to hold it.
Food would slip off your fork which you would not have been able to hold
in the first place. You know that people used to rub two sticks together
to start fires. The fire starts because of the heat caused by the
||The inclined plane is a
kind of simple machine with slanted surface. On mountains or steep
hills, roads, and walking trails don't go straight up the mountain.
It would be too difficult to walk or drive that way. Instead, the
road winds back and forth up the mountain. These inclined planes
are called switch backs, which are easier to climb.
The pyramids in Egypt are
made of huge stone blocks. For years people have been wondering how
they moved all those heavy blocks around. The best guess is the Egyptians
pushed the blocks up inclined planes in order to build the pyramids.
||The lever is simple machine
made up of a stiff arm or arms that pivots or turns. The point that
a lever turns on is called the fulcrum. The load is the force of the thing
you are trying to move. Over 2000 years ago, a Greek scientist named
Archimedes (ark a MEE dees) figured out how and why levers worked.
People had been using levers for a long time, but he was the first to explain
them using math. Legend credits Archimedes with saying, "With a big
enough lever, you can move the world."
||The pulley is a simple machine
made of a rope or chain wrapped around the wheel. A movable pulley reduces
the amount of force needed to lift an object by object by increasing the
distance over which the force is applied. The useful pulley is one of the
earliest and simplest wheel devices. Back in the eighth century B.C.,
the country that is now Syria may have discovered that a small wheel within
a frame made it easier to pull up a heavy weight hanging from a rope running
over the wheel. Engineers in ancient times used this knowledge to
their advantage in the construction of many monuments and temples.
||The wheel and axle is a
simple machine made of a large wheel attached to a post or axle.
Spanish speaking people arrived in California with their own mining technology.
The arrastre worked much like a wheel and axle. An upright
post was turned by a mule walking on a circular path. The post, twirling
a granite block, ground up rocks that contained gold.
||The wedge is two inclined
planes joined back to back. Wood has been the main medium for crafts
and construction among the Alaskan Natives and American Indians of Northwest
Coast region. When building their wooden plank houses, one of the their
main tools was the wedge. Hardwood wedge enable workers to split
long planks from tree trunks. Other wooden products of the American
Indians include totem poles, canoes, masks, containers, figurines, tools,
||The screw is an inclined
plane wrapped around a post. One of the first screw machines was invented
by Archimedes in the third century B.C. Archimedes, perhaps the greatest
mathematician of his time, designed a machine to lift fresh water from
the hold of a ship belonging to King Hiero II of Syracuse. Archimedes'
machine had a watertight cylinder enclosing a spiral running from end to
end (something like the inside of a mincer), with its lower end immersed
in the water. As the machine was turned by hand, the water collected in
the rotating spiral blades and was lifted out of the ship's hold.
The Chinese invented
the wheelbarrow almost two thousand years ago. They called their
invention the "wooden ox" or "gliding horse." A worker could push
it or pull it. Almost 1,300 years passed before Europeans learned
of this labor saving device and copied it.
|Students should have
the following skills before the unit begins:
1. Use of a calculator
to multiply and divide.
2. Basic understanding
3. Basic knowledge
of a accessing the Internet
4. Computer reference
5. Basic knowledge
6. Familiarity with
how to work in cooperative groups