Starting materials list: ruler, paperclip (or florist wire), pencil, coins (quarters, dimes, etc).
Directions for building a lever:
1. Untwist paperclip and wrap it around your pencil.
2. Take the pencil and place a ruler on it.
3. Put quarters on the ruler and push on the other side.
Examples of levers in real life:
Knife
Soda can opener Seesaw
Creative ways that levers have been used in mechanical engineering:
Scissors are a creative lever that you use in every day life. And seesaws are fun things you can find at parks when you play with your friends
Challenge:
Can you think other ways levers are used?
Simple Machine: Lever
Simple Machine: Pulley
Starting Materials List:
3 People, 2 Broomsticks (or dowel rod or pvc pipe), 20’ Rope, Gloves (optional)
Directions for Building a Pulley 1. Three people.
2. Assign two volunteers as broom-handle holders and the other as the rope puller.
3. Have the two broom-handle holders wear gloves and stand about 5 to 6 feet apart and extend their arms to hold the broom handles parallel to the floor at waist level.
4. Securely tie one end of the rope to the middle of one of the broom handles.
5. Wrap the rope around the middle of the other broom handle (see Figure 1) and give the free end to the rope puller. The rope puller should stand behind, and slightly to the side of one of the holders, so that the rope will be pulled perpendicular to the length of the broom handles. The free end of the rope should go under the arms of the broom-handle holder so that the rope is pulled parallel to the ground as well. See Figure 2.
6. Have the two broom handle holders try as hard as they can to prevent the broom handles from coming together as the rope puller pulls on the rope.
Examples of Pulleys in Real Life:
Elevators Wells
Theater Curtains, Window Blinds Flagpoles, Clotheslines
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Pulleys are used extensively when heavy objects need to be lifted, especially in cranes in shipping and construction areas. Pulleys are one of six types of simple machines used to easily change the direction and/or the magnitude of an applied force. (The lever and fulcrum, inclined plane, wheel and axle, wedge, and screw are the five other types of simple machines.) How does a
pulley decrease the amount of force necessary to lift an object? The advantage of a pulley is its ability to change the number of “ropes” lifting an object. This gives a lifter a greater mechanical advantage. Mechanical advantage is a ratio of the output force compared to the input force. The greater the mechanical advantage is for a system, the greater the output force is compared to the input force. The greater the mechanical advantage, the easier it is to do the work. For a block and tackle pulley system, the mechanical advantage is determined by the number of support ropes that are lifting the object (see Figure 3). Therefore, the more times the rope is wrapped around the broom handles, the greater the mechanical advantage is for the puller.
Creative ways that pulleys have been used in mechanical engineering:
Starting materials list: duct tape, broom handle, cardboard box, cardboard tube from a paper towel roll, two rolls of toilet paper, two plastic grocery bags, and some string.
Directions for building a simple wagon:
1. Take the cardboard tube and duct tape it to the underside of the box so that it runs down the center of the box.
2. Put the broom handle through the cardboard tube.
3. Cover the rolls of toilet paper with the plastic grocery bags. This will keep the toilet paper from unrolling. Slide the rolls of toilet paper onto either side of the broom handle. Duct tape these in place.
4. Poke a hole into the cardboard box, and attach a string through the hole.
5. Experiment with your newly created wagon! Try to determine how much easier it is to pull a heavy load in the wagon than it is to carry it yourself.
Examples of wheel and axle in real life:
Steering wheel
Cars, trucks, wagons, carts, skateboards, bicycles Windmill
Door knob Analogue clock Crank
Pulley Rolling pin
Creative ways that the wheel and axle have been used in mechanical engineering:
Mechanical engineers design and build all kinds of machines. They have used the wheel and axle for building tanks for the army, and robots that help rescue animals caught in a burning building.
Simple Machine: Wheel and Axle
• Pictures of simple wagon: Top and bottom views.
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Simple Machine: Wedge
Starting Materials List for Hammer and Chisel : Legos
Directions for Building a Hammer and Chisel:
You can easily build a wedge out of LEGO bricks by creating two large triangular shapes that are the inverse of each other, and can be set atop one another. You just want to make sure that one end is a blunt point.
To build a LEGO Hammer, make sure that you create a handle out of 6X2 Legos. We used 7 of them. Then Create a flat head that connects to the handle. We used a mixture of 5X2, 2X2, and 4X2 LEGOS.
We’ve included pictures of our Hammer and Wedge. You can be creative and create your own!
Creative ways that the wheel and axle have been used in mechanical engineering:
A wedge is a triangular shaped tool. It can be used to separate two objects or portions of an object, lift up an object, or hold an object in place. It functions by converting
a force applied to its blunt end into forces perpendicular to its inclined surfaces.
The mechanical advantage of a wedge is given by the ratio of the length of its slope to its width. Although a short wedge with a wide angle may do a job faster, it requires more force than a long wedge with a narrow angle.
Examples of Wedge in real life:
Fork: It is made up of 4-5 wedges put together. It can be used to split food apart.
Knife: A Wedge with a sharpened edge that can cut objects into pieces.
Doorstop: Used to hold doors in place. It’s a wedge that goes between the door and the floor.
Ax: Used to split wood. You used the hammer to drive the wedge into the wood causing the wood to split apart.
Hammer and Chisel:used to make statues and what you just made!
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Starting materials list: Look around your building or neighborhood for a wheel chair ramp next to a stairway. Or lay a board across some stairs. Be sure they start at the same level and end at the same level.
Directions for experimenting with an inclined plane:
1. Build the simple wagon described in the lesson on “Wheel and axle”.
2. First, try to pull the loaded wagon up the wheelchair ramp.
3. Second, try to pick it up and carry it up the stairs.
4. Which is easier?
Examples of inclined plane in real life:
Truck loading ramp Wheelchair ramp
Creative ways that the inclined plane have been used in mechanical engineering:
Mechanical engineers design and build all kinds of machines. An inclined plane lets them move heavy things uphill more easily. They have used the inclined plane to build roller coasters, and ramps for arthritic dogs to climb up into their beds.
Simple Machine: Inclined Plane
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Simple Machine: SCREW
Materials list:
Apple Corkscrew
Instructions:
Stab corkscrew into apple and twist
Examples of a screw in real life:
Apple or grape presses Faucets
Corkscrews Drill Bits
Boat Propellers Jar Lids
Electric Fans
Mechanical Engineering and Screws:
A screw is an inclined plane wrapped around a single core into a spiral shape. Screws can do 2 things. They can convert a force that goes around and around into a force that goes up and down (this is a cider or grape press, for example). A screw can thread into things like wood or metal, so that the two items are joined together and not easily
