e-mail: earthfriends@rdslink.ro

Spoken words are in blue

Scene: It is a hot summer day. Child 1 and Child 2 are in a hurry to reach the meeting place to exchange postage stamps. Everyone has a stamps holder full of lovely, interesting stamps. They meet together in the park and are now shaking hands like real businessmen ready to start their important work.
Not far away, a bench is heated by the pitiless sun’s rays.
In an instant both of them decide to sit on the bench and start the exchange of stamps. But… both of them are jumping-up immediately because the bench is burning their skin. They seem scared looking the bench, unable to understand what is happening.
In the same moment, Father stops nearby and cannot resist smiling - looking at the children’s faces.

Father: For sure you’ve encountered one of the effects of solar radiation, haven’t you? Maybe it would be better to find a place in the shade.

Child 2: Won’t the bench be hot there?

Father: Why not find out for yourself?

Child1: Does this mean there is no solar radiation occurring?

Father: No, solar radiation is influencing the whole planet, however hot or cold the weather. Without solar radiation life is impossible. Only the shadow produced by trees or buildings or other obstacles situated in front of the solar rays is protecting us against the overheating of our body and offering a more pleasant place to sit. But here we are. What do you say about that bench? Don’t be scared. So, what do you say?

Both children, together: Much better!

Child 1: You know, we wanted to make some stamp exchanges, but why not tell us more about the power of the Sun?

Father: Let’s start, then!
The Sun is a star with its own heat. The Sun has a very high temperature, it is incandescent and it lights all the planets around it. It is not only lighting them but it is heating them more or less, depending on the distance between it and them. A large part of the Sun’s heat is lost in space and just a small part is heating our planet, the Earth. The Sun radiates 174,423,000,000,000 kilowatt hours of energy to the Earth per hour. In other words, the Earth receives 1.74 x 1017 watts of energy.

Both children, together: Wow! No wonder the bench was hot!

The atmosphere, the air blanket that surrounds the Earth, also captures some of the heat coming from the Sun, and the oceans as well as the glacial areas situated at the N and S poles, are reflecting heat back into space like mirrors. However, as you’ve felt on your skin, the heat that touches the land and all the objects and beings existing on Earth- is quite significant. That’s why your mothers gave you white hats, to protect you against the excessive heat because black coloured clothes capture heat rather than offering protection from it.

Child 2: If solar radiation is so strong, it would be interesting to use it. For example, isn’t it possible to use it instead of using gas for kitchen stoves? Wow, I’m on the way to an epochal discovery! Cooking with the Sun!

Child 1: OK, I understand, you are always hungry, that’s why you are speaking only about cooking. But I can invent a system able to heat water with solar radiation.

Father: Excellent! Both of you have brilliant ideas, but unfortunately or maybe fortunately these inventions were made many years ago. People have been using the Sun’s power to heat water and to preserve food for thousands of years.

Child 1 and Child 2 are looking very sad.

Child 1: For a moment thereI thought I’d be the youngest inventor in the world…

Father: Don’t worry. In a way you are inventors because you didn’t know that all those things have already been invented. But you can be also creators of equipment that use solar energy.

C1 and C2 are happy

Both children, together: Great, but how, what can we do?

Father: If you want, we can go to my workshop and with some luck and skill, we will enjoy some food prepared with the Sun. That’s OK for you?

Both children, together: Let’s go now!

Child 1: …To eat something… Laughs

On the way the group walks nearby a kiosk with two red plastic tables and white plastic chairs. Father invites the kids to touch with their fingers first the red tables and then the white chairs.

Child 1: The table seems to be even hotter than the bench.

Child 2: But the chair is not hot at all. How is it possible? Hmm, that means the red colour is attracting the solar radiation and the white colour is reflecting the heat.

Father: That’s right. Do you know, black attracts most of the Sun’s rays.

Child 1: Don’t mirrors reflect heat?

Father: The mirrors reflect not only the light but also heat. Based on this observation, people made concave mirrors (parabolic) that focus the heat in a point and in this way they are obtaining a very high temperature able to boil water in seconds. - Arriving at the workshop.- Here we are, and we'll start immediately to catch the Sun before it goes to bed. - Taking some paper out of a drawer.- First we make some drawings. Second we will make the solar cooking box.

Child 2: You too, with the food! I thought that only he - pointing at the other child - is the hungry one.

Father: I'll say! - I’m also hungry, but the main reason of choosing to build a solar cooking box is because its easy.

Father and children are doing the drawings - camera focus on the drawings while Father speaks about what they are doing.

The list of necessary materials and tools is also written down.

The camera is focussing on the materials and tools on a table. The explanations are coming from off camera.

They cut the cardboard boxes, aluminum foil, and they already have a steel plate and the glass to cover the boxes.

The work is finished and Father brings a pan with water and peaches. They will prepare peaches compote. The pan and its lid are black matt.

Father: Why do you think the pan and lid are matt black?

Child1: The red table was hotter than the whilte chairs and I remember you said that black attacts the most heat.

Father: Well done!

- They are going outside and place the cooking box in a sunny place.-

The sun is working…and, after one hour, three happy people are enjoying the compote made with Sun power. Clean and cheap - sustainable.