Lesson Plan

Teaching Sequence

Work through this resource material in the following sequence:

10 minutes

Tune In: What is value?

20 minutes

Find Out: What affects energy efficiency?

25 minutes

Take Action: How can we use our scientific knowledge to make better choices?

5 minutes

Reflection

Tune In: What is value?

Step 1

Ask students to head to a household appliance retailer's website, such as The Good Guys (https://www.thegoodguys.com.au/).

Advise students they have just moved into a new house with their family and must purchase a washing machine, fridge and air conditioner for their new place. They have a budget of $3000.

Refrain from giving your students any further instructions or information and allow them to choose the three items they think would be the best. They might focus on price, looks, brand, reviews or energy efficiency. The Good Guys website has a lot of information about the performance and efficiency of the appliances, which will come in handy as students progress through the task.

Once students have chosen their three items and added them to their cart (so they can quickly access them), discuss the following with your students

What appliances did you pick?
What were you looking for as you were choosing?
What is important to you in an appliance?
Did anyone have any different ideas?
Were you more concerned with the immediate cost or the cost over time? Do they know how the cost of an appliance can be different over time?
Did you have any environmental concerns?

Step 2

Explain to students that according to the Department of Industry, Science, Energy & Resources, household appliances account for around 30% of a home's energy use.

Ask students why this is an important statistic to know when we are considering the appliances we use in our homes.

You may like to brainstorm all of the impacts of using energy/electricity in their home. This can be informed from the previous lessons in this unit, where students discussed how electricity is produced and the effects this has on the environment.

Suggested Responses

Electricity is most often generated from the burning of fossil fuels. To produce electricity, carbon dioxide and other greenhouse gases are produced, which add to the greenhouse effect and increase climate change.
The more energy we use, the more it costs. When we are considering big appliances that are on a lot of the time, this is also a significant consideration.
If appliances are efficient, they will use less electricity to perform the same job, we don’t have to pay as much to run them and not as much electricity needs to be produced to meet the demand.

Step 3

Remind students of the Law of Conservation of Energy, which states that energy cannot be created or destroyed, only transferred or transformed from one form to another and the concept of energy efficiency, which comes from how much useable energy something produces compared to the amount of input energy that goes into it. (These concepts were covered in Lesson 1 and 2 of this unit; please refer to these lessons if your students haven’t covered these concepts.)

Discuss with your students - How does the law of conservation of energy relate to the energy efficiency of an appliance?

Any process or piece of equipment is unlikely to be 100% efficient. As energy is transferred and transformed, we lose energy along the way as unwanted transformations take place. For example, think of a light bulb. The desired product is light energy. In an ideal world, all of the electricity being transformed into the light bulb would be converted to light energy. However, these can often produce heat as waste - which lessens the efficiency of the bulb because we need to use more energy to achieve the same outcome.

Find Out: What affects Energy efficiency?

Step 1

Show your students the image of the three light bulbs on the attached visual explainer. There is an incandescent light bulb, compact fluorescent light bulb and an LED or light emitting diode. Explain to students that heat is a lightbulb's most often lost energy source.

Ask students just by looking at them which light bulb they think is the most efficient and least efficient and why.

Students may need a reminder that the most efficient means converts most of the electrical energy to light energy instead of other forms. Encourage them to explain their reasoning with reference to what they know of how energy is transferred and transformed and also how heat energy is lost most frequently.

Once you have finished discussing, show students the next images, which are labelled with what percentage of energy is lost as heat, as well as how many watts each light bulb uses.

Watts are a measure of energy transfer - calculated as volts x amps. Note that all of these bulbs would have similar brightness, the watts are a measure of how much energy they consume!

Show students the following short video from Neil Degrasse Tyson explaining the difference between old and LED lightbulbs.

LED Bulbs vs. Old Bulbs - @StarTalk (https://youtube.com/shorts/RKQlSUPMc0o?feature=shared)

Step 2.

Explain to students that there is a range of factors that affect the efficiency of appliances, this can be due to size, the internal components and circuitry, how they are used, and where they are used.

Ask students to choose a type of household appliance and research what affects its efficiency.

The appliances that consume the most energy are

Fridges
Ovens
Washing machines
Clothes dryers
Home entertainment systems,

But students may like to look at other appliances that they frequently use such as kettles, toasters, microwaves, gaming systems, or even rooftop solar panels!

Encourage students to look into

How the appliance works
What energy transformations need to take place
What types of energy are lost
How they have been designed to be more efficient (A reminder to students that this means producing the maximum amount of useful energy out of the total input energy!)
What we as purchasers can do to make them more efficient.

Note: Some examples of these can be found in the teacher content information to assist in your discussions with students.

Step 3.

Introduce your students to the Energy Rating Label, which is a part of the Australian and New Zealand Equipment Energy efficiency program

Ask your students - why would there be a governmental program focused on equipment efficiency?

Suggested response: Reduce energy use, reduce emissions and save money for consumers.

Students can see an example of the energy rating label on the attached visual explainer. The more stars, the more energy efficient. It also indicates how much energy would be used in a year by the appliance.

Take Action: How can we use our scientific knowledge to make better choices?

Step 1

Students are going to complete the Tune In Activity from the start of the lesson. This time, the brief has changed slightly!

The student's parents/guardians have asked them to take charge of the purchasing of appliances for their new house. But they have one condition - they need to know that scientific knowledge is being used in order to make the decisions, this means they need to understand the choices that students are making from a variety of viewpoints. Students need to present this information as a written report or presentation. The students have a budget of $3000 and need to purchase a fridge, washing machine and air conditioner. Students can complete this task individually or in groups.

The brief is as follows. The appliances for the new house should

Save as much money as possible, both in the short term and the long term
Have a high efficiency/energy rating.
Have a reduced environmental impact
Be well-functioning

Students will need to create a presentation for their parents justifying their choices that

Explains the initial cost as well as the cost of running the appliance over 5 years and how this is different from other appliances in that area
Explains the energy efficiency of the appliance using the energy rating
Explains how they can make it more efficient in the long run (e.g methods of use)
Explain how these appliances will have reduced impact on the environment compared to other choices

Resources to assist students

Energy Cost

This website finder.com.au gives the average price of electricity in each state per kilowatt hours. Explain to students that energy usage in your home is determined by how many watts you use in 1 hour, called kilowatt hours (1 kW = 1000 watts). Advise them to take note of the price of kilowatt hours in their state to help them calculate the running costs of their appliances.

Energy rating

The Energy Rating Label website from the Australian Government explains the energy rating system and has some more information, such as tips for buying appliances, which air conditioners are suitable for different climates, and how to calculate the cost of running an appliance based on its energy rating!
They also have an energy rating calculator to compare energy-efficient appliances!

Step 2

Depending on the amount of time you have, you might like to get students to pitch their presentations to the class and vote on which set of appliances they would buy based on how convincing the presentation was.

Optional Extension

Energy efficiency is an incredibly important aspect of the production of electricity as well as equipment and appliances we use not only at home but in businesses and industry as well. Electrical Engineers are the people who work to increase the energy efficiency of everything electrical - they just so happen to be one of the most in-demand jobs in Australia as we move towards a net zero economy! Students requiring extension or early finishers can look a little more into this using the Clean Energy Council resources

and also ‘The Million Jobs Plan: Powering jobs, wages and economic growth’, which is available online at The Million Jobs Plan - Beyond Zero Emissions (bze.org.au)

They can choose one of the engineering types listed on the website they have researched to prepare a job advertisement for a career that this industry needs. It should explain:

The type of engineering and what it is
Why this job is important
The potential growth in the particular industry
How many different types of jobs (and potential numbers) the industry or industries need
Why it would be a good job to go into for the future

Reflection

Ask students to reflect on today's lesson by answering the following questions

What was the most surprising thing you learned about the impact of appliances on climate change?
Imagine a world where all appliances are designed for maximum efficiency. How do you think this would change the environment and our daily lives

How can you personally contribute to a more sustainable future in your own life, starting with the way you use energy in your home?
Thinking about global futures, what have you learned that would help Australia achieve our greenhouse gas emissions targets?

Understanding Energy Efficiency of Household Appliances

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