Gears
Activity Guide
Gears are closely related to another form of simple machine, the
wheel & axle.
How are they similar? How are they different?
What other simple machine is part of a wheel and axle?
Hint: the center of a wheel and axle acts as a fulcrum!
Exploring the Gears Design Station
Use the plastic gears to create a gear train of two gears.
Turn the first gear.
This gear, to which force is first applied, is called the driver.
In what direction does the second gear move?
Do the gears move in the same direction, or opposite directions?
Try adding more gears to the gear train.
How does the direction of rotation change with each gear you add?
Use the magnetic gears to create a gear train that includes one
large and one small gear.
Can you count how many times the small gear rotates in the time that
that the large gear takes to make one rotation?
Look at the boat cart in the photograph above the Gears Station.
Why do you think the cart has such large wheels?
Challenge
Can you design an invention using the K’Nex gears? Simple machines
make work easier. What work will your invention make easier?
Inclined
Plane
Activity Guide
Did you use the entrance ramp to walk into the museum today?
If so, then you used an inclined plane. Inclined planes play an important
part in the simple machines family. Ramps, screws and wedges are all
forms of inclined planes.
Exploring the Inclined Plane Design Station
Try pulling the red car up the inclined plane by pulling the rope.
Now try changing the angle of the incline by moving the wedge.
Notice that the wedge is also an inclined plane.
Does increasing the angle of the inclined plane make moving the car
easier or harder?
Turn the spiral gravity stick upside down.
Watch the beads roll down the spiral. Can you see how the spiral is really
a continuous ramp or inclined plane?
This toy shows how a screw is also an inclined plane.
A screw is an inclined plane that wraps around a central axis.
The inclined plane creates the threads of the screw.
Try tightening one of the screws with widely spaced threads.
Now, try one of the screws with more tightly spaced threads.
Which is easier to turn? Does one feel more secure than the other?
Challenge
How many forms of inclined planes - ramps, wedges, screws - can you
find in the museum exhibits today?
Pulleys
Activity Guide
Pulleys, also called blocks, are used on boats to hoist sails,to haul
lobster pots, and to make a variety of jobs easier.
A block and tackle is a system of rope and two or more pulleys, rigged
together, usually for the purpose of lifting a heavy load.
Exploring the Pulleys Design Station
Experiment with the block and tackle activities. First, try lifting the
weight by hand. Then, use the block and tackle to lift the weight. Which
way is easier? How do you think adding more pulleys to the block and
tackle system would change the amount of force needed to lift the
weight? Why?
Pulleys can change the direction of an applied force.
Joshua James and his lifesaving crews used pulleys (or blocks) to rescue shipwreck survivors by breeches buoy. Try hauling the whip line on
the model breeches buoy. When you pull the line toward you, does the
breeches buoy move toward you, or away from you? Why?
Challenge
1. Can you use the LEGOs to design a ship has a block and tackle?
What kind of ship will it be? What job will the block and tackle do?
2. The breeches buoy was an invention that saved hundreds of lives.
Can you use pulleys or wheels to invent a new kind of rescue equipment?
Wheel
& Axle
Activity Guide
Can you find a picture in this room of a boat on a cart with wheels?
Why did the lifesavers use a cart with wheels to move their boat?
How did the cart make their work easier? Why are the wheels so large?
A wheel and axle are two cylindrical objects that rotate around a central
axis. The larger the radius of the wheel relative to the radius of the axle,
the greater the mechanical advantage. In other words, the easier it will
be to move a load.
Exploring the Wheel & Axle Design Station
Use the LEGOs to build two cars, each with four wheels.
Make one car using small wheels, and the other car using large wheels.
Roll the car with small wheels across the table, counting the rotations
of one wheel as you go. Now, roll the car with large wheels the same
distance, also counting the wheel rotations. Which wheels made more
rotations, the large or the small?
A pulley is a wheel and axle with a groove to hold a cable.
As a pulley, a wheel and axle can change the direction of an applied
force. Use the wheel and axle to try lifting a load higher than the point at
which force is applied. This is how cranes work.
Challenge
Experiment with the LEGOs wheels and axles.
Can you design a better boat cart?
Levers
Activity Guide
Look at the surfboat Nantasket.
The long steering oar is a lever used to steer the surfboat to a wreck.
The oars that the crew used to row the boat are also levers.
The oarlocks are the fulcrum. The rower applies the force.
The position of the fulcrum is different for different kinds of levers.
The seesaw in the museum’s Children’s Loft is a form of lever, with the
fulcrum at the center.What other levers can you find in the museum?
Exploring the Levers Design Station
Try lifting the lead weight using the lever with the fulcrum at the first
notch. Now, move the fulcrum to the second notch. Then, the third.
Does lifting the load get easier, or harder as you move the fulcrum closer
to the weight?
Now, try the fulcrum balance activity. Position the balance on the
center notch. Place a weight on each side of the balance bar. Can you
make the two weights balance by sliding the loads along the bar? What
happens if you shift the position of the fulcrum? Experiment with
different weights and positions.
Challenge
Can you design a lever that will lift a person, using only a board and a
brick? Experiment with the board and brick to see if you can lift a friend,
your teacher, your museum guide, or one of your family members.
Where do you have to place the brick in relation to the person to lift the
most weight?