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Unit 4: Energy (Part 1) Page 16
fulcrum or far? Where does the 3. Books, gallons of water or
load lift the greatest distance, near anything heavy that’s not
the fulcrum or far? fragile
Experiment: Third-Class Again, be careful with this. Don’t
use something that’s so heavy
Lever
someone will get hurt. Also, be
sure not to use something so
heavy that you break the wooden
lever. Last but not least, be sure to
keep your head and face away
from the lever. I’ve seen folks push
down on the lever and then let go.
The lever comes up fast and can
pop you pretty hard.
This fellow is the oddest of all. The
1. Put your fulcrum on the ground
third-class lever has the effort in a nice flat place.
between the load and the fulcrum.
Imagine Experiment 1 but this time
2. Put your lever on the fulcrum so
the fulcrum is at one end of the that the fulcrum is at the very end
board, the books are on the other
of the lever.
end and you’re in the middle. Kind
of a strange way to lift books huh?
3. Put your load on the lever at the
end farthest from the fulcrum.
A few examples of this are
tweezers, fishing rods (your elbow 4. Now, put yourself (the effort) in
or wrist is the fulcrum), your jaw
the middle of the lever.
(the teeth crush the load which
would be your hamburger), and 5. Lift. You may need someone to
your arm (the muscle connects hold down the lever on the fulcrum
between your elbow (fulcrum) and
your load( the rest of your arm or 6. Experiment with the effort
whatever you’re lifting)). Your (you). Move towards the fulcrum
skeletal and muscular system are,
and lift the load Then move toward
in fact, a series of levers! the load and lift. Where is it
harder(takes more force) to lift the
You need: load, near the fulcrum or far?
Where does the load lift the
1. A nice strong piece of wood. greatest distance, near the fulcrum
3 to 8 feet long would be or far?
great if you have it.
2. A brick , a thick book or a We’ve had a lot of fun levering this
smaller piece of wood (for
and levering that but now we have
the fulcrum)
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