Lesson Plan

Teaching Sequence

Work through this resource material in the following sequence:

10 minutes

Tune In: How do objects interact with light and heat?

20 minutes

Find Out: How do objects and the Earth interact with light and heat energy?

25 minutes

Take Action: Using your understanding of electromagnetic radiation

5 minutes

Reflection

Tune In: How do objects interact with light and heat?

Step 1

Show your students the images of the coloured drink bottles on the attached visual explainer. The first slide contains images of three plastic drink bottles. 1 black, 1 clear and 1 white. Advise your students that they need to choose one of the drink bottles to take to the beach on a hot day.

Discuss with your students which one they would choose and why.

Your students may have some prior knowledge of the way different colours absorb and reflect heat and light, to keep the drink colder for longer, the white bottle would be most useful as white reflects light, whereas the black colour absorbs light and heat.

Step 2

Show students the next image on the visual explainer, which shows three black drink bottles all made of different materials. Again, ask your students which bottle they would choose to bring to the beach on a hot day.

Most of your students will have seen insulated bottles before and should be able to say that this would keep their drink cold for the longest. If you have completed the previous lesson in this unit concerning thermal energy, students should be able to describe how insulation affects the heat conductivity of an object.

Once students have provided their suggestions for both scenarios, discuss with them based on their observations - what properties affect how an object interacts with light and heat?

The material the object is made of
The colour of the object
The way light is able to pass through the object.

Step 3

Explain to students that light and heat are forms of electromagnetic radiation. You may like to show your students the image of the electromagnetic spectrum on the attached visual explainer. Watch the following video to show your students this concept:

Heat Transfer: Radiation - The Animated Teacher (https://www.youtube.com/watch?v=OYW7lR-XuJA)

Students should know that infrared radiation is a type of energy that humans cannot see, but we can detect as heat. It travels to Earth from the Sun in the form of electromagnetic waves, which don’t need a medium to pass through. However, all objects with thermal energy will emit some type of infrared radiation - this is why thermal imaging cameras work! These waves can travel through empty space. This makes it different from other forms of heat transfer, such as conduction and convection, which rely on particles to transfer heat energy.

Note: In the previous lesson in this unit, students learned about thermal energy and how it can be transferred through radiation, convection and conduction. An understanding of these processes would be useful in understanding the content of this lesson.

Explain to your students that radiation from the Sun in the form of infrared and visible light is what we will be focusing on in this lesson - specifically, how it relates to climate change and how we can utilise these properties to make design decisions!

Find Out: How do objects and the Earth interact with light and heat energy?

Step 1

Watch the following video with your students, which focuses on infrared radiation and its significance in the world around us.

Tour of the EMS 04 - Infrared Waves - ScienceAtNASA (https://www.youtube.com/watch?v=i8caGm9Fmh0&t=298s)

As they watch, ask students to note down some responses to the following questions:

What is the difference between infrared and visible light?
- They have different wavelengths - we can detect visible light with our eyes, but we cannot detect infrared with our eyes.
What do they have in common?
- Both are forms of electromagnetic radiation and can come from the sun
What can happen to infrared radiation when it reaches Earth from the Sun?
- Some can be absorbed by our Earth's surface or atmosphere, some can be emitted back into the atmosphere after it has been absorbed, and some can be reflected off surfaces

What does infrared radiation have to do with climate change?
- Certain gases in our Earth's atmosphere, such as the greenhouse gases water vapour and carbon dioxide, absorb much of the emitted radiation. This absorption leads to the heating of the atmosphere, which plays a significant role in our Earth's energy budget. In turn, it can lead to an imbalance in our Earth's radiation budget, impacting the atmosphere's temperature and contributing to climate change.

Step 2

Explain to students that how an object interacts with infrared radiation and light depends on its properties

Watch the following videos with your students, which show simple experiments of how radiation in the form of visible light and infrared interacts with different materials.

Science With Sabrina 👩‍🔬: Colors And The Heat - 5NEWS (https://www.youtube.com/watch?v=Nv8whXqr4sQ)

Infrared Radiation Absorption - GCSE Physics Practical - vt.physics (https://www.youtube.com/watch?v=EAIKFO8QD2U)

Discuss with students what they could see happening in these two videos. What properties determined how well energy was absorbed?

The colour of the object: darker colours absorb more heat
The type of material, metal can absorb more heat before it changes (melts)
The shiny nature of the material (shiny materials can reflect more heat and light)

Step 3

Ask your students how this might work on a global scale. What surfaces would reflect the most heat back into space? What surfaces would absorb the most heat? Encourage them to think big picture, as in surfaces that cover large areas of the earth's surface, not individual materials.

Reflect - Deserts, Snow and Ice
Absorb - Oceans and Earth

Students might have an awareness of the fact that the ocean's temperatures are rising as we encounter climate change, as well as Earth's average temperature. As this happens, there are fewer white reflective surfaces of ice and snow as they melt due to increased temperatures. Ask your students what they think this means for climate change in the near future.

This has to do with the Albedo effect. Light-coloured surfaces like Ice and snow reflect light and heat from the sun, whereas dark-coloured surfaces absorb this energy.

You may like to watch this video with your students that explains this concept a little more

How the Climate System Works: Ice Albedo - Innovera (https://www.youtube.com/watch?v=ClHojDSgxBQ)

Discuss with your students what solutions might be to reducing this feedback loop.

The biggest one is reducing our emission of greenhouse gases in order to stop the effects of climate change. However, this is a much bigger concept to tackle that involves far more than radiation. There are climate engineering solutions that include approaches to reduce radiation in our atmosphere, however, these are costly, big projects and won’t affect all aspects of climate change, such as ocean acidification. If your students are interested in this, they can read more about it here from Geoengineering.global.

On an individual level, we can make small changes utilising these concepts! One involves using our knowledge of heat transfer absorption and reflection to make our homes more energy efficient. Since buildings and their construction account for approximately 25-30% of greenhouse gas emissions, largely in part due to their energy consumption, this is a great area to use this knowledge in!

Take Action: Using your understanding of electromagnetic radiation to design

Step 1

To introduce this activity to your students, you might like to watch this video with your students, although it isn’t necessary. This video describes how engineers utilise their knowledge of heat and the principles above to design comfortable houses that conserve energy!

Note: Some of the concepts in this video are a little complex, but it is an excellent overview of how heat energy can be harnessed through transfer as well as the aspects of radiation. Your students won’t need to understand the equations.

Heat Transfer: Crash Course Engineering #14 - Crash Course (https://www.youtube.com/watch?v=YK7G6l_K6sA)

Step 2

Divide your students into groups of 3 and provide them with various materials, different colours, reflective and non-reflective surfaces and different types of materials. These could include the following, but use whatever you have available.

Paper
Cardboard
Aluminium foil
Polystyrene
Clear plastic sheets
Fabric or cotton
Paint
Sponges

Their task is to design a tiny house out of materials to ensure the inside can be as cool as possible. The design of this house can be simple: a box with four sides and a roof. Students may like to include windows or doors. Students will place a thermometer inside of their tiny house and use a heat lamp to radiate energy to the house. You can frame this as a competition - the coolest temperature inside the tiny house at the end of 10 minutes wins! For a fair experiment, ensure that each group's lamp is the same distance and height away from the house, and the house sizes are roughly the same. This can be a design sprint challenge where each group only has 10 minutes to plan and execute their design, or you could allow a little longer!

Encourage students to measure the starting temperature of their house and the end temperature. To practice collecting data and track the change over time, you might like to get students to measure the temperature every minute and graph this later on.

Step 3

Once you have finished the activity with your students, discuss the results.

What houses performed well?
What houses didn’t perform well?
What features enabled the structures to stay cool inside?
What features didn’t?
Did any students use innovative and creative ways of keeping their house cool?
If we could upscale these features to normal houses, what would that mean for energy consumption in a house?

Reflection

Encourage students to reflect on today's lesson by answering the questions below

What are three questions you have from today?
Thinking about what you learned today, why is it important for society to use scientific knowledge to reduce the impact we are having on the environment?
How might society use this scientific knowledge to reduce the impact we have on the environment?

Thermal Energy and Efficiency: Harnessing Electromagnetic Radiation

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UN Sustainable Development Goals

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