Simple machines lab
General Directions: Put things back as you found them at each station! You may need to use your simple machine notes to help you answer some of the questions!
I) LEVERS
DIRECTIONS:
A. Examine the model of the First Class Lever. Push down on the lever at different places – the yellow tile, closer to the fulcrum, etc.
1) Depending on where you push, how is it easy or hard is it to lift the load?
B. Examine the model of the Second Class Lever. Lift under the handle at different places – the yellow tile, closer to the fulcrum, etc.
2) Depending on where you lift, how is it easier or harder to lift the load?
C. Examine the model of the Third Class Lever.
Lift under the handle at different places – the yellow tile, the end of the handle, etc.
3) Depending on where you lift, how is it easier or harder to lift the load?
II) WHEELS AND AXLES
MATERIALS:
2 car models Test track
DIRECTIONS / QUESTIONS:
Look carefully at Model #1.
1. How easy do you predict it will it be to steer your model around corners?
What actually happened when you steered it around the test track?
Look carefully at Model #2.
2. What’s different from Model #1? (It’s hard to see – look closely!)
3. How easy do you predict it will now be to steer this Model around corners?
What actually happened when you steered it around the test track?
4. What difference does it make when wheels are on separate axles as compared to wheels on the same axle?
III) FIXED PULLEYS
MATERIALS:
Single wheel pulley Heavy string Spring scale
Cross bar cup of washers
DIRECTIONS / QUESTIONS:
1. Lift the cup of washers using only the spring scale. How much force was used to lift the washers?
B. Set up the Fixed Pulley as shown in the illustration.
2. Pull down on the spring scale to lift the washers. How much force was used to lift the cup of washers?
3. As you pull down (use force), in what direction does the cup travel?
4. Did using the pulley affect the amount of force needed to lift the cup?
5. Did using the pulley make the cup move in the opposite or same direction as the force?
6. What is the advantage of using a fixed pulley?
IV) USING A WEDGE
MATERIALS:
2 wood blocks thick rubber bands 1 wedge
DIRECTIONS / QUESTIONS:
Tightly wrap each rubber band twice around the wood blocks as shown in the picture.
1. Can you EASILY pull the blocks apart with your fingers?
Push the sharp edge of the wedge between the 2 blocks, and try to separate them. DON’T BREAK THE RUBBER BANDS!
2. Were you able to separate the blocks?
3. How did the wedge help separate the blocks?
4. What are two wedges that are used every day? Explain what they’re used for.
V) INCLINED PLANE
MATERIALS:
1 book String Smooth flat board
Spring scale Stack of books to prop up the board
DIRECTIONS / QUESTIONS:
Use the board and stack of books to make an inclined plane as shown in the picture.
1. Pull the book up the inclined plane with the spring scale. What is the force used?
2. Lift the book with the spring scale from the table top up to the same height as the top of the inclined plane without using the board. What is the force used?
3. Which way was easier (used less force) to lift the books?
4. Why?
VI) WHAT IS A SCREW?
MATERIALS:
Large pencil or dowel rod Marker Sheet of white paper Large screw Scissors Ruler
DIRECTIONS:
* Cut a piece of paper diagonally from corner to corner making a triangle as seen in the picture. Make a heavy dark line with the marker along the longest edge of the triangle.
* Wrap the triangle around the dowel rod, beginning with the shortest side as shown, making sure the
marker line is showing.
* Hold the wrapped dowel rod next to the large screw.
QUESTIONS:
1. How do the heavy lines on the triangle look like the threads on the screw? Explain.
2. Think about how the marker-drawn line on the triangle looked before it was wrapped around the dowel rod. How do the threads of a screw compare to an inclined plane?
3. Which distance is greater, the path up the side of the dowel rod (labeled “A”) or the path spiraling around it (labeled “B”)? Measure both with the ruler and record your answers below:
Path “A” straight up the side of the dowel rod _________________________ inches
Path “B” spiraling around the dowel rod _________________________ inches
4. What is the advantage of using a screw?
I) LEVERS
DIRECTIONS:
A. Examine the model of the First Class Lever. Push down on the lever at different places – the yellow tile, closer to the fulcrum, etc.
1) Depending on where you push, how is it easy or hard is it to lift the load?
B. Examine the model of the Second Class Lever. Lift under the handle at different places – the yellow tile, closer to the fulcrum, etc.
2) Depending on where you lift, how is it easier or harder to lift the load?
C. Examine the model of the Third Class Lever.
Lift under the handle at different places – the yellow tile, the end of the handle, etc.
3) Depending on where you lift, how is it easier or harder to lift the load?
II) WHEELS AND AXLES
MATERIALS:
2 car models Test track
DIRECTIONS / QUESTIONS:
Look carefully at Model #1.
1. How easy do you predict it will it be to steer your model around corners?
What actually happened when you steered it around the test track?
Look carefully at Model #2.
2. What’s different from Model #1? (It’s hard to see – look closely!)
3. How easy do you predict it will now be to steer this Model around corners?
What actually happened when you steered it around the test track?
4. What difference does it make when wheels are on separate axles as compared to wheels on the same axle?
III) FIXED PULLEYS
MATERIALS:
Single wheel pulley Heavy string Spring scale
Cross bar cup of washers
DIRECTIONS / QUESTIONS:
1. Lift the cup of washers using only the spring scale. How much force was used to lift the washers?
B. Set up the Fixed Pulley as shown in the illustration.
2. Pull down on the spring scale to lift the washers. How much force was used to lift the cup of washers?
3. As you pull down (use force), in what direction does the cup travel?
4. Did using the pulley affect the amount of force needed to lift the cup?
5. Did using the pulley make the cup move in the opposite or same direction as the force?
6. What is the advantage of using a fixed pulley?
IV) USING A WEDGE
MATERIALS:
2 wood blocks thick rubber bands 1 wedge
DIRECTIONS / QUESTIONS:
Tightly wrap each rubber band twice around the wood blocks as shown in the picture.
1. Can you EASILY pull the blocks apart with your fingers?
Push the sharp edge of the wedge between the 2 blocks, and try to separate them. DON’T BREAK THE RUBBER BANDS!
2. Were you able to separate the blocks?
3. How did the wedge help separate the blocks?
4. What are two wedges that are used every day? Explain what they’re used for.
V) INCLINED PLANE
MATERIALS:
1 book String Smooth flat board
Spring scale Stack of books to prop up the board
DIRECTIONS / QUESTIONS:
Use the board and stack of books to make an inclined plane as shown in the picture.
1. Pull the book up the inclined plane with the spring scale. What is the force used?
2. Lift the book with the spring scale from the table top up to the same height as the top of the inclined plane without using the board. What is the force used?
3. Which way was easier (used less force) to lift the books?
4. Why?
VI) WHAT IS A SCREW?
MATERIALS:
Large pencil or dowel rod Marker Sheet of white paper Large screw Scissors Ruler
DIRECTIONS:
* Cut a piece of paper diagonally from corner to corner making a triangle as seen in the picture. Make a heavy dark line with the marker along the longest edge of the triangle.
* Wrap the triangle around the dowel rod, beginning with the shortest side as shown, making sure the
marker line is showing.
* Hold the wrapped dowel rod next to the large screw.
QUESTIONS:
1. How do the heavy lines on the triangle look like the threads on the screw? Explain.
2. Think about how the marker-drawn line on the triangle looked before it was wrapped around the dowel rod. How do the threads of a screw compare to an inclined plane?
3. Which distance is greater, the path up the side of the dowel rod (labeled “A”) or the path spiraling around it (labeled “B”)? Measure both with the ruler and record your answers below:
Path “A” straight up the side of the dowel rod _________________________ inches
Path “B” spiraling around the dowel rod _________________________ inches
4. What is the advantage of using a screw?