How does a wheelbarrow help you carry heavy loads?
How does this align with my curriculum?
In this hands on activity build a wheelbarrow from simple materials to explore just how useful simple machines can be!
What You Need
- Small box (e.g., facial tissue or shoebox) - 1
- Drinking straws ~10
- Cardboard paper towel tubes – 4
- Coins, metal washers or other small objects
- Film canister lids (with nail-sized holes in middle) or empty thread spools - 2
- Masking tape
- Scissors
What To Do
- Lay 10 straws parallel to each other on a tabletop. These are your rollers.
- Place the box on top of the straws and push the box. How easy is it to move the box?
- Now repeat steps 1 and 2 using the paper towel rolls instead of the straws. Is it easier or harder to move the box using the larger rollers?
- Load up the box with cargo, using coins or washers. Lift it using just four fingers. How much cargo can you lift?
- Empty the cargo out of the box.
- Make holes for an axle at one end of the box. Use scissors to punch holes large enough for a drinking straw to pass through the short side of the box (See photograph below of wheelbarrow construction).
- Slide a straw through these holes so that the ends of the straw stick outside the box on each side.
- Attach a film canister lid or thread spool to each end of the straw axle. Use tape as necessary.
- To make handles to lift the wheelbarrow, tape paper towel tubes to the end of the box opposite the wheels.
- Put the load back into the box and try pushing your wheelbarrow. How easy is it to move the load now? What is the role of the handles?
Discovery
Rollers have been used since ancient times to move heavy objects without having to lift and carry them. The problem with rollers laid out on a track is that it is difficult to change direction and the travel distance is limited by the length of the track. So, the axle was invented, which is more portable, and allowed people to easily move heavy cargo over long distances with wheels of various sizes. Large wheels and rollers require less effort to move than small wheels and rollers.
Attaching handles extends the length of your wheelbarrow, so it can better act as a lever. A lever is a bar that pivots on a fixed point of support, called a fulcrum. In this wheelbarrow, the axle, raised up by the wheels, acts as the fulcrum point. When trying to lift the cargo load, it should be easier with the axle acting as the pivot and lever-like handles.
Rollers, wheels and axles are examples of simple machines. These machines help us to do work but they do not have any power of their own. A wheelbarrow is an example of a complex machine. A complex machine consists of two or more simple machines working together and it may have a power source. In a wheelbarrow there are wheels and an axle, an inclined plane and a lever (handles), but there is no power source.
- Is the wheelbarrow lever system more effective at lifting a load placed closer to the wheels or closer the handles?
- How could you improve your wheelbarrow to make it even easier to lift and move the load?
- Where else around your home can you find wheels and levers?
For more information on this topic check out these Let's Talk Science resources:
Simple Machines - Levers (Backgrounders) - Have you used a lever today? Learn about the different classes of levers and how they provide mechanical advantage in this backgrounder.
Simple Machines: Levers (Picture Collections) - Here are six images of objects that use the lever principle to create movement for a specific purpose.
What’s happening?
Rollers have been used since ancient times to move heavy objects without having to lift and carry them. The problem with rollers laid out on a track is that it is difficult to change direction and the travel distance is limited by the length of the track. So, the axle was invented, which is more portable, and allowed people to easily move heavy cargo over long distances with wheels of various sizes. Large wheels and rollers require less effort to move than small wheels and rollers.
Attaching handles extends the length of your wheelbarrow, so it can better act as a lever. A lever is a bar that pivots on a fixed point of support, called a fulcrum. In this wheelbarrow, the axle, raised up by the wheels, acts as the fulcrum point. When trying to lift the cargo load, it should be easier with the axle acting as the pivot and lever-like handles.
Why does it matter?
Rollers, wheels and axles are examples of simple machines. These machines help us to do work but they do not have any power of their own. A wheelbarrow is an example of a complex machine. A complex machine consists of two or more simple machines working together and it may have a power source. In a wheelbarrow there are wheels and an axle, an inclined plane and a lever (handles), but there is no power source.
Investigate further
- Is the wheelbarrow lever system more effective at lifting a load placed closer to the wheels or closer the handles?
- How could you improve your wheelbarrow to make it even easier to lift and move the load?
- Where else around your home can you find wheels and levers?
For more information on this topic check out these Let's Talk Science resources:
Simple Machines - Levers (Backgrounders) - Have you used a lever today? Learn about the different classes of levers and how they provide mechanical advantage in this backgrounder.
Simple Machines: Levers (Picture Collections) - Here are six images of objects that use the lever principle to create movement for a specific purpose.