Minds On
Devices
Explore the following carousel of common devices.
A carousel of four images.
Image 1: A large plastic tub attached to the top of two long wooden handles that connect to a wheel and axle under the front of the tub. Each handle has a metal leg attached to it under the back of the tub, keeping the tub upright.
Image 2: A skinny metal rod with a tip shaped like a four-pointed star attached to a plastic handle with wide grooves for gripping.
Image 3: A child’s hand gripping a round metal handle attached to a wooden door.
Image 4: A wide cylinder made of solid wood with an axle going through its centre that is attached to skinny wooden handles on both ends.
- What is similar between these devices?
- What is different between these devices?
- What do you think is the purpose of each device?
Record your responses using a method of your choice.
Action
Machines
A machine is anything that makes a force stronger.
To perform work, a pushing or pulling force is needed, which can be provided by a human or a machine. Simple machines are the basic mechanical machines that allow humans to apply more force to an object.
Explore the following image of the six basic simple machines.
In this learning activity, you will be exploring a few of these simple machines in greater detail, focusing on their ability to make motion. You will be investigating the wheel and axle, the pulley, and gears.
Wheel and axle
The wheel and axle are two pieces that work together to form a simple machine that has been used to make work easier for people. It uses a wheel with a rod attached through the middle that can spin if it is pushed or pulled. This simple machine can help move and lift loads.
What is a load?
A load is the object that is being lifted, moved, or affected.
Brainstorm
Wheel and axle machines
- Can you think of any machines that use a wheel and axle?
Record your ideas in a method of your choice.
Press ‘Answer’ to access one possible answer.
A bicycle and car are two examples of machines that use a wheel and axle to move a load.
On a bike, force is applied when someone pedals and causes the wheels to turn. The wheel and axle changes the direction of the force so that the bike moves in a linear (forward, straight) direction.
This is similar to a car, in which the axle connects to the wheels on the car, and when the axle is turned, the wheels turn together, allowing the car to move forward or backward.
Roller
A roller is slightly different from a wheel. A roller is a long, cylinder-shaped object that can be used to help move heavy loads.
The roller was invented before the wheel and is longer in width. Rollers were originally used by ancient Egyptians to move large stones for their pyramids. At that time, they used tree logs as rollers.
Today, rollers are used in conveyor belts to move packages or groceries, for example. A roller does not move with objects, so you need a lot of rollers to cover a significant distance.
Innovation in Canada
This learning activity features emerging technologies, STEM contributions, and Canadian innovations that are making a difference.
Did You Know?
Canadian contribution: a better paintbrush
How does painting walls in a bedroom relate to the wheel and axle?
Norman Breakey, who lived in Toronto, Ontario, understood the connection. Breakey realized that using a paint brush to paint large rooms took a long time, because the brush could only put small amounts of paint on the wall at a time. So, with a little thought and the use of a simple machine, the wheel and axle, Breakey invented the first paint roller.
A paint roller
The cylinder covered in cloth acted like a wheel, and the part of the handle that extended into the cylinder became the axle. After pouring paint into a tray, Breakey could roll paint onto the roller and then roll the paint onto the wall.
The absorbent material used on the roller held more paint than a regular paint brush, and the surface area of the cylinder was large, allowing for more wall to be painted at one time. These advantages resulted in less work being done by the painter.
Breakey’s innovation saved time and work for painters for years to come!
A wheel works just like a roller, except the wheel moves with the object that it is attached to. The reason a wheel can move with the object is because of the axle.
Friction is the force that makes it hard to slide or move two objects against each other. A wheel makes objects easier to move because of friction. When you roll a wheel, only a small portion of the wheel is touching the ground at any time. This means there is less friction between the ground and the wheel.
Check your understanding so far using the sorting interactive below!
Pause and Reflect
Roller versus wheel
- Explain the difference between a roller and a wheel.
Record your response using a method of your choice.
Gears
A gear is a wheel with teeth that slot together so that, when one gear turns, the other will turn as well. Gears are made in different sizes in order to increase the power or speed of the turning force.
Gears are also used in bicycles, and are connected by a chain. The chain works the same way as the gear because it has teeth that connect two gears – one from the back wheel and one from the pedal. As someone pedals a larger gear, the chain transfers the turning force from the pedals to make the gear on the wheel rotate, which moves the bike.
Explore the following video of bicycle gears.
There are several different types of gears.
Press the following tabs to access descriptions and images of the types of gears.
The most common gears are called spur gears. Spur gears move in one plane and are commonly used in clocks, toys, and machinery.
An idler gear is one in which all gears are facing the same direction. The idler gear is important because it is used to change the direction of the gear.
A bevel gear is a type of gear that uses two different gears that fit into each other at an angle. Bevel gears are used to operate in two different planes of motion – vertical and horizontal.
Worm gears are used when large gear reductions are needed. This means that when a gear needs to slow down, the worm gear is used, because they tend to have much fewer teeth than the spur gear.
Image 1: Two circular gears with equally sized teeth interlocked into each other’s equally sized slots. Image 2: Two large circular gears with equally sized teeth interlocked into the equally sized slots of a small circular gear between them. Image 3: Two circular gears with equally sized angled teeth interlocked at a 90-degee angle into each other’s equally sized slots. Image 4: One circular gear and one cylindrical gear with equally sized teeth interlocked into each other’s equally sized slots.
Pause and Reflect
Types of gears
- Why are there different types of gears that all work together to help a machine run?
Record your ideas in a method of your choice.
Press ‘Answer’ to access one possible answer.
Different types of gears are needed because they all serve a different function. Some gears speed up the machine and others slow it down. Some gears are needed to change the direction of a force, and others maintain that direction.
Converting motion
So far, you have learned about the wheel and axle and gears as two components that help machines work. Both of these machines convert rotary motion to linear motion.
What is rotary and linear motion?
- Rotary motion is when something turns around in a circle, such as a wheel turning.
- Linear motion is when something moves in a straight line, such as a car driving forward.
Press the following tabs to access different ways to convert rotary motion to linear motion.
A wheel and axle can use rotary motion to create linear motion. One example of this is a well. A well often uses a wheel and axle to pull water out of the ground. By cranking the wheel, a rope wraps around the rod, which then lifts the bucket full of water. A human applies the rotary force to the crank, and the load (water) is lifted straight up.
Explore the following video of a well being used and try to identify where the wheel and axle are.
Gears can be used to create rotary motion that can be transferred to linear motion.
Gears provide a rotary force that turns around in a circle. This turning force can be used for simple tasks, like turning a screwdriver to put a screw in the wall, or it can be used to create linear motion, which is used to complete many tasks in our everyday lives. For example, a clock pendulum transfers rotary motion to oscillating (back and forth) motion.
Explore the following video of rotary motion used to create oscillating motion.
Rotary motion can be converted to linear motion by using a system called a rack and pinion.
The pinion is the normal round gear and the rack is the straight or flat gear. These two gears fit together as the pinion rotates along the straight rack. As the motion of the pinion rotates through the linear rack rotary motion is converted to linear motion.
One circular gear and one flat gear with equally sized teeth interlocked into each other’s equally sized slots.
Engineering a water wheel
Another everyday example of rotary motion that creates linear motion is a water wheel.
A water wheel is a device that takes advantage of flowing or falling water to generate power. The force of the water causes the wheel to rotate, and this rotation can then be changed into linear motion with the help of gears and levers to complete a variety of tasks.
Explore the two following videos of water wheels.
Since water is a renewable energy source, the wheel will continue to produce energy for a long time.
What is renewable energy?
Renewable energy is made from resources that nature will replenish, like wind, water and sunshine. Renewable energy is also called “clean energy” or “green power” because it doesn’t pollute the air or the water.
Uses for water wheels
While water wheels are not in operation as much today, they once used to grind grain.
As the water wheel turns, its main shaft enters the basement of the grain mill to turn a complex set of gears. These gears turn to power machinery that grinds the grain. Explore the image of a water powered grain mill.
Click the image to enlarge in a new window.
Water Powered Grain Mill
Water wheels were also originally used for grinding wood into pulp to make paper, hammering iron, preparing fiber to make cloth, and to mill flour.
Did You Know?
Hydroelectricity
The simple principles of the water wheel were used to design innovative energy solutions, such as the hydroelectric dam. The hydroelectric dam uses the power of water to turn a generator that produces energy. This energy is converted to electricity that can be used by communities.
Can you think of any other uses for the waterwheel? Maybe you can come up with a whole new way to create power! Begin by exploring the Engineering Design Process.
Engineering design process
Check out this video to learn about the steps of the Engineering Design Process.
Designing a water wheel
In this activity, your task is to design a water wheel that serves a function and uses both rotary and linear motion. If possible, you can build a prototype of your water wheel.
Press ‘Hint’ to access an idea to help guide your design.
You could design a water wheel to service a function that already exists, or you may wish to create power in a new way.
Complete the My Water Wheel Design Activity in your notebook or using the following fillable and printable document. If you would like, you can use speech-to-text or audio recording tools to record your thoughts.
Press the Activity button to access My Water Wheel Design Activity.
Activity (Open PDF in a new tab)Consolidation
Check your understanding!
Check your understanding by completing the following fill in the blanks interactive.
For each sentence, select the missing word from the drop-down menu.
For each sentence, select the missing word from the drop-down menu.
For each sentence, select the missing word from the drop-down menu.
Reflect and connect
Reflect on the steps you took while creating or describing your water wheel and respond to the following questions.
- What went well?
- What changes, if any, would you make if you were to recreate your water wheel?
- Did anything surprise you?
Record your responses using a method of your choice.
Presenting my water wheel design
The last step of the engineering and design process is to share your design or prototype with others. In a method of your choice, create a short presentation about the water wheel device that you designed. Use the following checklist to help you create your presentation:
Presentation checklist
Answer the following questions to create your water wheel presentation.
Reflection
As you read through these descriptions, which sentence best describes how you are feeling about your understanding of this learning activity? Press the button that is beside this sentence.
I feel…
Now, record your ideas using a voice recorder, speech-to-text, or writing tool.