The Power of the Sun

PDF version coming soon

Age group 3rd – 6th class
Total time: 1hr – 1.5hrs

Outline: To learn about solar energy and why renewable energies are better for the planet

Links to Primary Curriculum Key Learning points

The child should be enabled to
– learn that light is a form of energy
– investigate how mirrors and other shiny surfaces are good reflectors of light (Science: Light)
– know that heat energy can be transferred in solids (conduction), in water and air (convection), from the sun (radiation)
– explore and experiment with the properties and characteristics of materials in making structures (Area: Arts Education, Visual Arts)

This activity will cover:
– Why renewable energies are better for our planet
– How solar energy can be converted to heat energy
– How heat energy can be transferred between different materials

Notes for parents/carers and teachers

This activity can be carried out at home by a child/small group of children and an adult, by varying the types of age-appropriate tasks. The materials are available at home or easily obtainable. The activity is written out with instructions directed to the child’s parent/carer. Feel free to adapt this activity as appropriate.

What you need

Use reused/recycled materials where possible (box, old tinfoil etc)

Cardboard box/pizza box/shoe box, black paper, tinfoil, cling-film, small plate, short stick/twig, tortilla chips, shredded cheese, timer, styrofoam/other insulation material(optional), garden thermometer (optional)

1. What do you know about the Sun’s energy?

Questions to ask the children to start them thinking

What do you know about the different types of energy we use in our homes every day? (electrical, gas, solar, wood etc..) Do you know where they come from? (fossil fuels or renewables?) Do you know what are renewable energies? Does your house or school have solar water heating panels or photovoltaic panels on the roof? Let’s find out more about why we should use renewable energies in our homes and everywhere.

Why Renewable Energy?

We all know that climate change is already greatly hurting the planet and many people. We need to act fast to drastically reduce our use of dirty energy from fossil fuels which cause climate change. Reducing energy use and using greener renewable energies is vital. Renewable energy is energy that is collected from renewable sources, which are naturally replenished on a human timescale (it can be created again in one human life time), such as sunlight, wind, rain, tides, and waves. If we use more energy like energy that comes from the sun, we can help to reduce climate change. Let’s experiment with the sun and see what we can do!

Feel free to add these interesting facts into the conversation.

Did you know?

  • Earth receives more energy in one hour from the sun, than our whole planet uses in one year!
  • Since the 1950’s, space shuttles have used solar energy to power their space craft.
  • Ireland gets enough sun to use solar water-heating panels to provide 60% of the hot water in our homes

2. Let’s make yummy nachos

Note: Pick a sunny warm day for this experiment, and set the oven up by about 1pm to catch the warmest part of the day.

SOLAR OVEN
the open tinfoil-covered lid helps to reflect
more sun rays into the box

1. Having gathered the necessary materials, let your child build their own oven. Here are some pointers and key questions to help them out. They can see the photos and videos first and then decide their own design.

Think about how to best make your oven. Check the box is just big enough to fit a small plate inside, but it’s best if it’s not too big (it takes longer to heat). Think about what material will heat up most in the sun (black paper)? What material will reflect the sun’s rays the most (tin-foil)? What part of the box do we want to heat up most (the plate of food in the centre)? What material is best for a lid (see-through cling-film), so the sun’s rays can still get in? Make sure to seal the oven lid very well to keep in the heat.

2. Set the solar oven in a sunny spot facing the sun, but best sheltered if possible from any breeze.

3. Add the nacho chips and top with shredded cheese,with a thermometer inside if you have one. Seal the see-through lid very well so heat cannot escape.

4. Set a timer for 15 minutes. Record your results. Check every 15-30 minutes until the cheese melts. It will depend on how sunny and how hot the day is.

5. Once the cheese has melted, eat and enjoy!

6. If your cheese didn’t melt much, why not try improving the design of your solar oven? Did you seal the oven top properly? Could you make your box keep the heat in more? How? Make some changes and compare your results. THINK like a scientist. A real scientist carries out experiments many times to collect data and to figure out better and more efficient ways of doing things.

If you liked this experiment and still want more, think about what else you could cook in your solar oven? Melted chocolate on crackers? Invent something yummy!

3. How do sun rays melt our cheese?

Prompt them with some questions like these below. You can then read the full explanation to them, or better still, put it into your own words.

Key questions

On a sunny day, would you feel hotter in a black t-shirt or a white one? Why do you think the solar oven you made heats up more than a plain box lying in the sun? What does the black paper do to the sun’s rays ? What does the tin-foil do to the sun’s rays? How does our plastic cling-film lid help us heat the box? What else could you do to make the solar oven heat up even more? (If your design is somewhat different, think about your materials and how they work)

Explanation

Converting sunlight to heat energy

The rays emitted by the sun have a lot of energy in them. When those rays strike something, whether it’s solid, liquid or a gas, this energy is passed into the small particles or molecules in that substance, by making them vibrate inside in a tiny tiny way. This generates heat in that substance, and makes it heat up. When sun rays pass through the air and heat it up, it makes all the gas particles move and flow together. This is called convection. When the sun rays hit the cheese directly, they also cause the solid cheese molecules to move more slowly and heat up. This is called conduction.

Dark surfaces get very hot in sunlight, whereas light coloured surfaces don’t. They can absorb more of the heat energy from the sun rays. Light coloured surfaces don’t absorb much of the heat energy; instead it bounces or reflects back off them.

Retaining heat

Our transparent cling-film lid helps us keep the heat in the box, creating a heat trap, that melts the cheese. This is very like much what happens in our earth’s atmosphere because of certain gases that cause it to overheat. This is called the Greenhouse Effect which is happening to our whole planet with Climate Change. Can you explain why it is called the Greenhouse effect?

Look at the following National Geographic video and see how useful solar cookers are in other parts of the world.

Now that we’ve seen what solar energy can do, how else could we use it around our house, or other buildings? What else could we use solar energy for? Do some research on solar hot water heating and solar panels.

4. What did you like? What did you learn?

Adults and children are both welcome to answer.

What did you like most/least about this experiment?

What did you learn about solar energy and the Greenhouse Effect?

What else would you like to try in this experiment if you did it again?

5. Our Brightest Stars

Did you know that the Sun is our closest star? People who like to study the stars are called astrophysicists. Jocelyn Bell Burnell is an astrophysicist born in Belfast in 1943. Her father was an architect for the Armagh Observatory, where young Jocelyn spent much time as a child. She loved looking up at the stars and then reading about them. She was so fascinated by them that she wanted to study them when she grew up.

As a postgraduate student in Cambridge in 1967, she discovered the first radio pulsar – a spinning neutron star. These are old stars which are at the last stages of their lives. While analysing data from a radio telescope she noticed some unusual signals that were fast and regular like radio signals. Bell Burnell and her supervisor Anthony Hewish figured out that these signals must have come from rapidly spinning, super-dense, collapsed stars, which are now known as pulsars. This was one of the most significant scientific achievements of the 20th century.

In 1974, Anthony Hewish was awarded the Nobel prize in physics for the discovery of pulsars, but Jocelyn Bell Burnell was excluded, despite having been the first to observe and precisely analyse the pulsars.

The decision not to award her with the prize was heavily criticised by prominent astronomers at the time. After this, Bell Burnell went on to win a number of awards for her scientific work.

In 2018, she was awarded the Special Breakthrough Prize in Fundamental Physics. Following the announcement of the award, she decided to give the whole of the £2.3 million prize money to help female, minority, and refugee students seeking to become physics researchers. Jocelyn Bell Burnell is still working in the field of astrophysics and astronomy at the University of Oxford.

6. Extra Resources

The Educator’s Spin on it – Learning activities and games

How Solar Cookers Work

EPA Primary resources – Natural Resources

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