Elenco Solar Energy User Manual

SUN POWER

Make your own solar energy lab!

Tree of Knowledge

WARNING:

BE CAREFUL WHEN USING PARTS WITH SHARP POINTS OR EDGES.
KEEP AWAY FROM CHILDREN UNDER THREE YEARS OF AGE.
ALL EXPERIMENTS THAT ARE IN DIRECT SUNLIGHT SHOULD BE
PERFORMED WHILE WEARING SUNGLASSES.
ADULTS ARE ADVISED TO READ MANUAL AND SUPERVISE WHEN
NECESSARY.

© 1999 Tree of Knowledge (1979)

No park of this publication may be reproduced or transmitted, in any form or
by any means, without permission in writing from the publisher.

THE PARTS IN YOUR KIT

parabolic reflector

test tube

reflector pin

reflector support

lens

support
reinforcer

thermometer

heat absorber bag

test tube holder

(tube and scale)

LETTER TO SUPERVISING ADULT

Dear Adult,

This solar energy kit has been designed for children from the age of 8 and up. It is
primarily for playing with, and learning about solar energy and temperature. While
performing the activities, one learns how to conduct and follow them through, as well
as learning how to draw conclusions.

The theory behind solar energy is difficult. We have attempted to explain a very small
part of this theory. It is not essential for the child to read or understand this theory,
however, if you can explain, it would be helpful for encouraging the child to learn.

In the booklet, there are several experiments/activities which require certain household
objects. The opportunity for the child to look around the house and search for each
item is valuable as this helps to show that science is part of everyday life.

Most of the activities can easily be performed by children, however, we do suggest that
you read this short booklet together with the child. You may feel that there are
certain activities which are not suitable for your child at this stage of his/her
development. There are a few experiments which we feel require adult supervision.
These experiments are marked with this sign:

When working with the child, it is important to stress that all parts of the kit not in use
should remain in the box. After experimenting, the parts should be returned to the box.

This kit must be kept out of reach of children below the age of three years as it
contains small parts that may be choking hazard.

We hope that both you as an adult, and the child playing with this kit will enjoy
experimenting and learning together.

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TABLE OF EXPERIMENTS

Experiment no. 1 The thermometer
Experiment no. 2 Converting sunlight into heat
Experiment no. 3 Sunlight shining through a window
Experiment no. 4 The heat from an electric light bulb
Experiment no. 5 Black water
Experiment no. 6 The solar heater
Experiment no. 7 Solar heater and reflected light
Experiment no. 8 Solar heat can be reflected
Experiment no. 9 The solar pond
Experiment no. 10 Determining the focal point
Experiment no. 11 Burning a feather
Experiment no. 12 Singeing a piece of rubber
Experiment no. 13 Cold water in sunlight
Experiment no. 14 Dark liquids in sunlight
Experiment no. 15 Influence of ink
Experiment no. 16 Brewing tea
Experiment no. 17 Melt a candle
Experiment no. 18 Frying an egg white
Experiment no. 19 Additional sunlight
Experiment no. 20 The focal point of lens
Experiment no. 21 Concentrated heat
Experiment no. 22 Charring paper
Experiment no. 23 A lense’s shadow
Experiment no. 24 The solar trap
Experiment no. 25 Homemade solar reflector
Experiment no. 26 Alterations and variations

INTRODUCTION TO SUN POWER

The energy we use today is usually obtained from fossil fuels, such as oil, gas or coal.
Even electricity is a fossil fuel, because most of the electricity generated today is made
by burning one of these three kinds of raw material.

Fossil fuels like coal, gas and oil, which we use for things like heating, lighting, and
cooking, won’t last forever. One day the world’s supply will run out. So what will take
their place? One possibility is energy from the sun. which we call solar energy. For
many years now scientists have been developing ways of collecting and using solar
energy, because it is clean, sate and something the world cannot run out of – though
obviously some parts of the world have more of it than others!

The experiments in this kit should give you some idea about how the sun’s rays create
energy. As this kit deals with solar energy, there are some experiments that may not
give you good results without strong sunlight. These experiments are marked with this
sign:

You will find a few experiments that require adult supervision. These experiments are
marked with this sign:

After reading this short introduction, you are ready to start with your experiments.

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Experiment no. 1 The thermometer

There are many types of thermometers; the one enclosed in your kit is the most
common kind. It contains a bulb of liquid at one end and a long thin bore which runs
up the center of the glass tube. When the liquid in the bulb is heated, it expands and
moves up the bore; when it is cooled, it moves down.

To determine the temperature we see how far the liquid has moved up or down
the bore and read off the temperature from the plastic base.

The scale of your thermometer is calibrated in both the Celsius and Fahrenheit scales.

The Celsius (sometimes referred to as
Centigrade) scale is the one most commonly
used in scientific work. On the Celsius scare

o

is the freezing point of water and 100o is

0
the boiling point of water. The range between
the freezing and boiling point of water is divided
into 100 equal parts of degrees. Degrees Celsius
are written as oC.

The United States still uses the Fahrenheit
scale of temperature, you will very often come
across this unit of temperature measurement.
In the Fahrenheit scale water freezes at 32

o

and boils at 212o . The temperature range
between the freezing and boiling point of water
is divided into 180 equal parts of degrees. The
common abbreviation for a degree Fahrenheit
is oF.

TEMPERATURE SCALE CONVERSION
FAHRENHEIT- CENTIGRADE- KELVIN

water boils

human body
temperature

220

200

180

160

140

120

100

110

100

90

80

70

60

50

40

380

370

360

350

340

330

320

310

room temperature

There is one other temperature scale which
is in common use in more advanced scientific
work; it is the Kelvin scale. Knowing that a

water freezes

gas when cooled one degree centigrade loses
1/273 of its pressure, Lord Kelvin reasoned
that at 273oC below zero –absolute zero – a
gas would not have any pressure. He devised
a scale where 0oK is that theoretical point
where gases do not exert any pressure and
each degree is identical to a degree centigrade.

Included here you will find a comparative
chart of all these temperatures.

WARNING: Your thermometer is only capable of measuring up to 50oC.

Make sure that you do not leave it in boiling water, which is 100
or 212oF.

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80

60

40

0

-20

-40

-60

30

20

10

0

20

-10

-20

-30

-40

-50

o

C,

300

290

280

270

260

250

240

230

220

Experiment no. 2 Converting sunlight into heat

This experiment seems so easy, elementary, even childish, that you probably won’t
want to try it! Go ahead, do it all the same. It is worthwhile!
Take 3 transparent cups of the same size that are either glass or plastic. Place one on
a dark sheet of paper and two on white paper. Stand these outside in sunlight and pour an
equal amount of cold water into each, about half a cupful should be enough. Measure
the temperature of the water in each with the thermometer.
Now, cover one of the cups that is on the white paper, with a transparent saucer, or even
some cling film.

Measure the temperature of the three cups

-after 10 minutes

-after 30 minutes

-after 60 minutes

Did you notice any differences? Did any of the results surprise you?
Some facts to help you with your observations and recordings:
a) A dark background generally absorbs more heat than a light background.
b) Glass or plastic absorbs a small quantity of the sun’s ray.
c) The glass of plastic retards the evaporation of water.
d) When water evaporates, some of the heat is lost since it is used up during the
evaporation process.

Experiment no. 3 Sunlight shinning through a window

Repeat Experiment No. 2, but this time, perform it on a table in a room with the
window closed. In other words, you will test sunlight which has passed through glass
windows.

Before you start, have a guess what the results might be. Even the scientist who
developed these experiments was not sure what the results would be until he tried it!

Experiment no. 4 The heat from an electric light bulb.

What would you expect to find if, instead of sunlight, you were to use the light of an
electric lamp on the ceiling of your room? Try it.

An electric light bulb gives out heat. It is absorbed in the room and y our thermometer
is not sensitive enough to register the difference.

Experiment no. 5 Black water

Supposing you were to dye the water you place in
the glasses black. Would you expect to obtain a
higher temperature? Could this idea be put to practical
use? Perhaps you could design an experiment to test
this idea (hypothesis).

cartridge

If you have no black ink, you could make some by
dripping some water into the top of a dried felt tip
pen, collecting the water as it emerges from
the bottom. As an extra bonus, the dried out felt

ink

tip pen will write again!

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