Energy

# Water wheel investigation

Explore how energy can be converted from potential to kinetic.

• Hands On
• 40 mins

#### Overview

By building a water wheel, your students can see how energy is converted between potential and kinetic. The water wheel also provides an opportunity to explore variables that can solve real problems. The teaching notes below provide background information on potential and kinetic energy.

#### What you'll need

• An aluminum pie pan
• A ruler
• A piece of string, about 50 cm in length
• Hex nuts or metal washers
• A pencil
• Scissors
• Tape or glue
• A source of water, like a faucet or fountain
• "Water wheel investigation" worksheet (1 per student)

#### Instructions

As a class, review the terms work, energy and power and discuss the relationship between the three concepts (see the teaching notes, below, for more content).

Ask students where they have seen water wheels in the world, and what they were being used for. Water wheels convert potential energy to kinetic energy and perform work.

#### Building a water wheel

Organize your students into pairs, and have them complete the "Water wheel investigation" worksheet as they go.

1. Have students cut out the bottom of an aluminum pie pan to create a circle.
2. Next, students should make six to eight, evenly-spaced cuts in the aluminum circle, stopping 2 cm from the centre. Referring to the diagram, students should cut along the dotted lines.
3. Using a ruler, students can fold one edge of each section. Each fold should be in the same direction. Referring to the diagram, the folds should be made along the solid lines.

1. Students can then punch a hole in the centre of the wheel. They should take the pencil and push it through the centre hole, and secure it with tape or glue.
2. Tie the hex nut or washer to one end of the string, and use tape to attach the other end of the string to the pencil.
3. Have students hold the water wheel under the water source, allowing the pencil to turn in their fingertips.

Collect the "Water wheel investigation" worksheets and assess the students’ ability to:

• Build a working water wheel
• Describe the energy conversions
• Describe relationships between variables (water flow, speed of wheel)
• Evaluate design and suggest changes

Learn more about how energy is related to the concepts of work and power with the "Work, energy, power" activity.

Energy is the ability or capacity to do work and is measured in joules (J). Energy can be transformed into another type of energy, but it cannot be created and it cannot be destroyed.

There are many different forms of energy (heat, light, electric, elastic, etc.) but all energy is either potential or kinetic.

• Potential energy is stored energy that is available to do work. It can take forms such as chemical, mechanical, nuclear, gravitational and electrical. Examples include a mobile phone or car battery, a ball sitting on a table or a stretched rubber band.
• Kinetic energy is energy in motion that is actually doing work. It can take forms such as light, heat, motion and sound. Examples include a car in motion, a ball falling off a table or a rubber band flying across the room.

#### Grade 9 Science - Curricular Competencies

##### Questioning and predicting
• Demonstrate a sustained intellectual curiosity about a scientific topic or problem of personal interest
##### Processing and analyzing data and information
• Seek and analyze patterns, trends, and connections in data, including describing relationships between variables and identifying inconsistencies
• Construct, analyze and interpret graphs, models and/or diagrams
##### Evaluating
• Evaluate their methods and experimental conditions, including identifying sources of error or uncertainty, confounding variables, and possible alternative explanations and conclusions
##### Applying and innovating
• Generate and introduce new or refined ideas when problem solving

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