Thames & Kosmos 623715 User manual

WARNING — Science Education Set. This set contains
chemicals and/or parts that may be harmful if misused. Read
cautions on individual containers and in manual carefully. Not
to be used by children except under adult supervision.
EXPERIMENT MANUAL

Safety Information
Dear Parents,
This experiment kit will introduce your child to the exciting world of solar technology. Equipped with this manual and the material
in this kit, your child could well be on his or her way to becoming a future engineer designing high-tech energy systems.
But first, it is natural to have concerns about safety. The experiment set in front of you conforms to U.S. and European safety stan-
dards. These standards include requirements for manufacturers, but they also require that parents stand by their children’s side
with help and advice. Please tell your child to read all directions and safety instructions and to keep them close at hand for easy
reference. Emphasize to your child that he or she should always follow all the instructions and rules of the experiments.
For performing experiments without solar energy, a 1.5-volt AA battery is required, which could not be included in this kit due to its
limited shelf life. Please be sure to remove any dead battery from the kit and dispose of it appropriately.
We wish you and your young solar hobbyist a lot of fun and success with these experiments.
Safety Warning for Parents:
• Warning: Intended exclusively for children at least 8 years of age!
Safety Warnings for Children:
• Do not insert the cables into an electrical outlet.
• Do not connect the motor box to other power sources.
• The experiment kit should not be connected to other energy sources.
• Do not charge non-rechargeable batteries.
• Different battery types or new and used batteries are not to be used together.
• Use only the recommended battery types.
• Always insert batteries with positive and negative ends in the proper direction!
• Dispose of dead batteries properly and without delay.
• Do not attach the connection clamps to each other.
• Safety equipment, such as components for restricting current, should not be tampered with.
First Edition. Franckh-Kosmos Verlags-GmbH & Co. KG, Stuttgart/2004
This work, including all its components, is copyright protected. Any use, outside the specific limits of the copyright law,
without the consent of the publisher is prohibited and punishable under law. This applies specifically to reproductions,
translations, microfilming, and storage and processing in electronic systems. We do not guarantee that all material in this
work is free from other copyright or other protection.
© 2004 Franckh-Kosmos Verlags-GmbH & Co. KG, Stuttgart
Text: Tobias and Reinhold Pehle
Project Manager: Gerhard Gasser
Photos: Medien Kommunikation, Unna, up to p. 6, p. 7 top: Kopf AG, Umwelt- und Energietechnik, Sulz-Bergfelden,
p. 11 bottom: HONDA, Deutschland; Inside back cover: public domain image courtesy of NREL.
Original Layout and editing: FROMM MediaDesign GmbH, Selters im Taunus
Second Edition, Thames & Kosmos LLC, Providence, RI, U.S.A.
© 2006, 2012 English Translation
® Thames & Kosmos is a registered trademark of Thames & Kosmos LLC.
Translation: David Gamon
Editorial and Production: Ted McGuire
Copy Editing: Jed Wilcox, Christa Raimondo, Stephanie McQuillan
Printed in Taiwan/Imprimé en Taiwan
PRINTED ON RECYCLED PAPER

Experiment Manual
Tobias and Reihold Pehle
and David Gamon
Franckh-Kosmos Verlags-GmbH & Co., Stuttgart, Germany
Thames & Kosmos LLC, Portsmouth, RI, USA

Kit Contents
The crane hook and the cord holder (28) have to be fastened to the cord.
17
18
19
20
21
22
23 24
5
678
9
10
14
11
12 13
15
16
1
3
2
4
25
26
27
28
30
29
2

2 x base plate
6 x long frame
6 x short frame
8 x short rod
6 x long rod
4 x large gear wheel
4 x medium gear wheel
10 x small gear wheel
4 x small sprocket wheel
4 x medium sprocket wheel
4 x large sprocket wheel
1 x large pulley wheel
1 x medium pulley wheel
1 x small pulley wheel
4 x tire wheels
5 x long axle shaft
2 x medium axle shaft
5 x short axle shaft
1 x engine shaft
1 x black cable
1 x red cable
1 x battery holder
1 x solar panel
1 x solar engine
5 x shaft plug
28 x anchor pin
2 x attachment plates
1 x crane hook
with spool
and cord
200 x chain link
1 x anchor pin lever
Table of Contents
> For some of the experiments, you will also need:
l 1.5-V AA battery
l various lamps in the house, especially a desk
lamp with at least 75 Watts of illumination
l 1 sheet of tracing paper or transparent wax
paper
l even surface (e.g. tabletop or pavement)
l uneven surface (e.g. gravel path or lawn sur-
face)
l large, smooth, solid piece of cardboard (e.g.
back of a pad of 8 1/2 x 11-inch drawing or
writing paper)
l chunks of brick or rocks for a payload
l kitchen or postal scale
l small piece of cardboard (approx. 8 x 11 cm)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
No.
702 495
702 498
702 497
702 500
702 499
702 506
702 505
702 504
702 507
702 508
702 509
702 516
702 518
702 519
702 591
702 501
702 502
702 503
702 801
702 593
702 592
702 531
702 530
702 800
702 525
702 527
702 496
702 512
702 513
702 595
702 510
702 590
Quantity and Description Part No.
Contents List Tips and Tricks for Model Building and Experiments. . . 4
Follow the Instructions Closely ..................... 4
About Connecting Frames and Rods ................. 4
About Wheels and Pulleys ......................... 4
About Mounting Wheels .......................... 4
Understanding the Sun and Solar Power .............. 5
The Sun’s Energy ................................ 5
The Solar Engine ................................ 5
Where Does Our Energy Come From? ............... 6
History of the Solar Cell ........................... 7
How Does a Solar Cell Work? ...................... 7
Powering an Engine with the Energy of the Sun ....... 8
The Solar Module ................................ 8
Your New Solar Engine ........................... 8
Little Shadows .................................. 9
Artificial Clouds ................................. 10
Artificial Sun .................................... 10
The Artificial Sun’s Power ......................... 11
Ambient Light ................................... 11
Reverse Movement ............................... 12
Switching the Solar Module ........................ 13
Battery Power ................................... 13
Your First Solar Vehicle ............................ 14
Solar Tractor .................................... 14
Under the Artificial Sun ........................... 14
Driving in Reverse ............................... 17
A Drive in the Sunshine ........................... 17
A Drive on Bumpy Ground ........................ 18
A Downhill Drive ................................ 18
An Uphill Drive .................................. 19
Driving with the Battery ........................... 19
Your Engine’s Performance ........................ 19
Load and Speed .................................... 20
Conversion to a Transport Vehicle .................. 20
Adding a Load ................................... 21
Maximum Payload ............................... 21
Transporting a Load Uphill ........................ 21
Weight and Speed ............................... 22
The Purpose of Chains ............................. 23
Drive Chains .................................... 23
Too Tight or Too Loose ........................... 24
Caterpillar Tracks ................................ 24
Driving Over an Obstacle ......................... 25
Driving Over Uneven Terrain ...................... 25
Large Platform Elevator ............................ 26
Your Solar Car ..................................... 30
Truck with Large Cargo Bed ........................ 34
Large Drawbridge .................................. 38
“Iron Annie” Airplane .............................. 43
Windmill with Wind Wheels ......................... 48
Mobile Crane Car .................................. 54
Heavy Duty Construction Crane ..................... 59
Designing Your Own Solar Models .................... 64
3

Tips and Tricks for
Model Building and Experiments
Frames (2, 3) and rods (4, 5) are
connected to each other with the help
of the anchor pins (26).
The short end of the axle
shaft (16, 17, 18) is built
so that the shaft can’t
slip through a hole.
If wheels or pulleys are
mounted too close to
other components, it is
hard to turn them.
If a wheel is mounted too
tightly on an axle shaft,
you can push out the axle
shaft with another.
If wheels have enough
“play,” they turn easily.
short end
long end
Follow the Instructions Closely
With this experiment kit, you will assemble a variety of
solar models and conduct a lot of experiments. It is best to
assemble the models in order. Then, it will be easier for you
to construct the complicated models at the end. For all the
models, it is important that all the individual components
are put together properly. Only then will everything work
right. To help you with this, there is a picture correspond-
ing to every step in the assembly process. The instructions
that go with the picture tell you exactly which pieces to use.
Following each piece mentioned in the instructions, there is
a number in parentheses. This is the number that you will
find in the overview of the kit contents on pages 2-3. So if
you aren’t quite sure which piece you are supposed to be
using, you can check on pages 2-3 to verify exactly which
piece it is.
About Connecting Frames and Rods
The basic construction of all of
the models consists of frames
and rods, which are connected
to each other with the help of
anchor pins. Some anchor pins
are already permanently mounted
to all of the frames and rods. But
for most of the connections, you
will need the red anchor pins
(26). They are simply inserted
into the holes of the frames and
rods and serve to ensure a secure
assembly.
To make it easier to remove
the anchor pins from the holes,
your kit comes with a small tool,
the anchor pin lever (30). It has
two different sides, marked “A”
and “B.” The narrow side with the
“A” serves to lever out the anchor
pins. The other side, marked with
the “B,” is wider. You can use it to
remove shaft plugs (25) from the
frames or rods.
You can use the narrow side of the
anchor pin lever (30) to pull the
anchor pin (26) out again.
With the help of the shaft plugs (25),
you can mount individual gear wheels or
sprocket wheels to frames or rods.
The shaft plugs can be levered out with
the broad side of the anchor pin lever.
About Wheels and Pulleys
In this box of solar experiments, you
will find four types of wheels: gear
wheels (6, 7, 8), sprocket wheels (9, 10,
11), pulley wheels (12, 13, 14), and tire
wheels (15). They all perform different
functions.
Gear and sprocket wheels are used
in all of the models. They have two
functions: first, they serve to transfer
the rotary motion of the solar engine
to other components. Second, they
are used to secure axles (16, 17, 18, 19)
so that they don’t slip. The tire wheels
are used to transfer the power of a
vehicle’s engine to the ground surface.
The pulley wheels serve to guide the
cord. In most cases, wheels and pulleys
are secured with the help of the axle
shafts (16, 17, 18). You can also attach
wheels and pulleys to the engine shaft
(19) or secure them individually with
the small red shaft plugs (25).
About Mounting Wheels
The axle shafts (16, 17, 18) and the en-
gine shaft (19) each have two different
ends: one short and one long. On the
short end, wheels and pulleys can only
be pushed on a little way. But if you
push them onto the long end, you can
position wheels and pulleys wherever
you want on the shaft.
The short end is constructed in
such a way that the axle shaft can’t slip
through a hole. To secure an axle shaft
to a rod or frame, it will suffice to push
a wheel, sprocket, or gear onto the
long end to serve as a bracket. When
building a model, you have to pay close
attention to which direction an axle
shaft is inserted.
With all of the models, wheels and
pulleys have to be able to rotate freely.
Otherwise, the solar engine won’t be
able to turn them. For that reason, it is
very important that wheels and pulleys
have enough “play” — as the profes-
sionals call it — and not be mounted
too close to other components. So
always leave a little room between a
wheel or pulley and other components.
Then, everything will go smoothly.
Sometimes, it may be difficult to
remove a wheel from its axle. If that
happens, use another axle shaft as a
tool; hold the wheel tight and push
with the other axle shaft against the
axle that the wheel is mounted on (see
picture at right).
4

Understanding the Sun
and Solar Power
The Sun’s Energy
Have you ever really thought about
what the Sun means to us, and what
it does for us? Let’s start right at the
beginning, or more precisely, let’s start
early…
What happens when the Sun rises?
It gets light out. The Sun produces
light — just like a lamp, except much,
much brighter. As you know, you need
electricity to turn on a lamp. Electricity
is a form of energy. We can use this
electricity in many different ways, just
one of which is illuminating a filament
in a light bulb. The Sun, on the other
hand, needs no electricity to create
brightness. Actually, it is just the oppo-
site. The Sun is itself an energy source
that provides us with our daylight. Its
power is so great that not even all the
lamps in the world could produce as
much light as the Sun.
The energy from the Sun is called
radiant energy. About 600 million tons
of hydrogen are fused into helium
in the Sun’s interior every second,
producing a radiant energy of 63,000
kilowatt-hours per square meter
(kWh/m2). At a distance of 150 million
kilometers, where the Earth orbits the
Sun, the power of this radiation still
amounts to 1,400 kWh/m2 (or Joules).
Only about half of that energy is
absorbed by the Earth, while the other
half is reflected back into space.
The Sun’s radiation is highly vari-
able in different regions of the world.
That has to do with cloud cover and
the tilt of the Earth. In Pennsylvania,
about 1,000 kWh/m2 of solar energy
are available per year, while the figure
Solar cells make it
possible to convert
the Sun’s energy into
electricity. The Sun can
deliver 13,000 times
more electricity than
the entire world uses in
one year.
is about 1,700 in Los
Angeles, 2,000 kWh/m2
in the Caribbean, and
2,200 kWh/m2 in the
Sahara desert. Com-
pare these numbers to
the fact that the aver-
age American uses only
about 13,500 kWh in a
whole year.
We can do some
calculations to find that
the Earth gets about
5.45 x 1024 Joules of energy from the
Sun every year. That’s 545 with 22
zeros after it! To put this in perspec-
tive, the amount of energy produced
and consumed in one year by everyone
on Earth is only about 4.26 x 1020
Joules. Thus, the Sun gives us about
13,000 times more energy than we
consume in a year! This means that in
less than an hour, the Sun delivers as
much free energy as all of the Earth’s
inhabitants combined use in an entire
year. So scientists have naturally asked
themselves the following question:
How can we capture the Sun’s energy
and use it for other purposes?
This is where the solar cell comes in.
A solar cell is a device that converts
sunlight into electrical current. The
word “solar” comes from the Latin
language, in which “sol” means Sun.
There are many ways that solar cells
can be used. In this experiment kit,
we will be using the Sun’s energy to
power a small motor used in various
models. Solar cell technology is also
called photovoltaic technology.
The Solar Engine
You are probably already familiar with
many kinds of engines, such as the
gasoline-powered engines in cars.
Those only run as long as there is fuel
in the tank. And you know about toy
cars that run on batteries, which will
run only until their batteries are used
up. Both of these kinds of engines
have major disadvantages. First of all,
fuel and batteries are expensive. On
top of that, they pollute the environ-
ment. Cars emit toxic and environ-
mentally harmful gases. Used batter-
ies get thrown into the trash. Since
they contain environmentally harmful
materials, they have to be disposed of
in time-consuming and labor-intensive
ways. In addition, they add useless
mass to our landfills.
Your solar engine, on the other
hand, needs neither gas nor batteries.
After it is made, it produces its own
electricity for free, for a long time. It
creates no toxic gas emissions, nor
does it add to the landfill. So a solar
engine is environmentally friendly as
well as inexpensive.
There is one small disadvantage
to a solar engine. In order to run, it
needs light — ideally, bright sunlight.
Since sunlight doesn’t reach us
at night, a solar cell can only produce
electricity from the Sun’s energy dur-
ing the day. However, the electricity
produced by a solar cell from sunlight
can also be stored. To do that, you
need special rechargeable batter-
ies and extra equipment. In order to
produce and store as much electricity
as possible in a photovoltaic installa-
tion, at the level that a family might
need, you need a lot of solar cells.
These are housed in large, flat panels
or modules, which you can already see
on some buildings.
5

Did you know . . .
. . . that the temperature on the
surface of the Sun is over 6,000° C
(about 10,800° F)?
In the center of the Sun, the temperature is 15-20
million ° C (~27-36 million ° F). The diameter of the
Sun, at 1,390,600 km, is over 100 times that of the
Earth. Its surface is 12,000 times as great as that
of our planet. The Earth itself would fit into the Sun
1,300,000 times. If you picture the Sun as a ball
20 m across, the Earth would be about the size of
a soccer ball 2 km away. The actual distance of the
Sun from the Earth is about 149,500,000 km.
. . . and that the
Sun is only mid-
dle-aged?
Even though the Sun is
estimated to be about 4.6
billion years old, scientists
calculate that it will con-
tinue to shine at its current
energy level for another 5
billion years. So the Sun’s
energy will be available for
human usage for a long
time to come.
Where Does Our Energy Come From?
Most of the energy we use comes from the Sun, in one way or another. This table provides a lot of information about our
eight most popular energy sources, how they work, where they come from, and whether or not they are sustainable. Sustain-
able means that they can continue indefinitely without running out or causing other problems over time.
Name Examples Definition Energy Origin
Percentage of world’s
power coming from
this source
Is it renewable,
relative to
human life?
Fossil Fuels Gasoline in a car, oil in
a furnace, natural gas
stove, coal in a power
plant
Fossil Fuels are organic materials that release a lot
of heat when they are burned. The heat can be used
to heat water to turn turbines to generate electricity.
They also produce a lot of pollution when burned.
The remains of prehistoric plants
and animals, which grew and stored
energy from the Sun
Petroleum: 38%
Coal: 24%
Natural Gas: 24%
No, only over mil-
lions of years
Hydro Waterwheel used to grind
meal, hydro-electric
dam used to generate
electricity
Hydro power is simply power from falling water.
Today, it is mainly used in the form of dams that
trap water and funnel it through turbines to produce
electricity.
The Sun evaporates water from the
oceans, the evaporated water rains
out of the sky to help form rivers
which run back to the ocean.
7% Yes
Nuclear Big reactors in power
plants and submarines
A complex system sets off a chain reaction of fis-
sion, or splitting, of uranium atoms. This produces
lots of heat, which is used to spin turbines which in
turn produce electricity.
The energy stored in the bonds inside
uranium atoms
6% No, Earth has a
limited amount of
uranium in it
Geothermal Geothermal power plants Geothermal power is generated using heat from
deep inside the Earth to create steam which is used
to drive turbines to produce electricity.
The temperature at Earth’s core is
estimated to be 5,000 to 6,000° C.
This heat was originally generated
when Earth formed, and additional
heat is formed as radioactive elements
decay inside the planet.
<1% Yes
Solar Photovoltaics (solar
cells) produce electricity,
solar water heaters heat
water, solar towers col-
lect heat to turn turbines
to produce electricity
Solar power is energy from the Sun. It can be cap-
tured and converted into useful energy in a variety
of ways. Without the Sun, there would be no life as
we know it on Earth. All living things need energy
from the Sun, either directly or indirectly, to survive.
Nuclear fusion reactions in the Sun
fuse hydrogen atoms together into
helium atoms, yielding huge amounts
of energy.
<1% Yes
Wind Windmills, wind power
generators
Naturally occurring wind (moving air) is used to
turn turbines to generate electricity. In the past,
windmills turned wind power into mechanical
energy used to grind corn.
Winds occur on Earth for two reasons.
First, the Sun heats the Earth in
different places at different times,
causing certain areas to have warmer
air than others. This causes pressure
differences, and air will flow from
areas of high pressure to areas of low
pressure. This, combined with the fact
that Earth rotates, causes the winds to
blow as they do.
<1% Yes
Biomass/
Wood
Sugar cane converted
into a combustible fuel,
animal waste converted
into methanol fuel
Biomass is an umbrella term used to describe any
organic, non-fossil material that can be used as
fuel. It is often plant and animal “waste” products
that are not useful for another purpose. Biomass
commonly used for fuels includes corn stalks, sugar
cane, wood by-products, animal manure and even
household waste.
Biomass grows because of energy
from the Sun, either directly as in the
case with plants, or indirectly, as in
the case with animals that eat plants
to grow.
<1% Yes, theoretically
biomass can be
grown at the rate
it is consumed
for fuel
Tidal Turbines in tidal areas Tidal power is power from the movement of the
tides in the ocean. It can be harnessed by placing
turbines in parts of the ocean with strong tidal cur-
rents. The currents turn the turbines that produce
electricity.
The tides are caused by the gravita-
tional pull of the Sun and the Moon
on the water in the oceans.
<1% Yes
6

History of the Solar Cell
In 1839, the French physicist Alexandre-Edmond Becquerel
discovered that light can influence electrical processes. He
determined that metal electrodes immersed in acid produce
more electricity when they are placed in the sunlight. Later,
scientists named this the photoelectric effect, or photovol-
taic effect. This was a very important discovery because it
clearly showed that under certain circumstances, light can
be converted into electrical energy.
In 1883, an American inventor named Charles Fritts built
the first solar cell, but it was very inefficient. A lot of time
passed and a lot of research was done before the first mod-
ern solar cell was patented by another American named
Russell Ohl. In 1958, the U.S. sent the first solar-powered
satellite into space, showing how much photovoltaic tech-
nology had progressed in just over 100 years.
How Does a Solar Cell Work?
A solar cell is a flat device that uses an electronic compo-
nent called a semiconductor to convert photons, or the
massless particles of light energy, into electrical energy. The
semiconductor creates a voltage, or difference in electrical
potential energy, between two surfaces when it is exposed
to light. You can think of it like a battery, which also has a
voltage between to points. This is just a brief explanation
of how a solar cell works. To explain it more thoroughly, we
must first discuss electricity.
The phenomenon of electricity is nothing more than the
movement of negatively charged particles, called electrons,
through a material, called a conductor. Electricity flows eas-
ily through some materials, like metal, and poorly or not at
all through other materials, like plastic. We have discovered
materials, like silicon, which are naturally poor conductors
in pure form, but can be treated to become better conduc-
tors under special conditions. These are semiconductors.
In a solar cell, electrons are excited into motion by
exposure to energy from light. The solar cell is designed to
make the electrons flow in a specific direction, creating a
negative pole on the side where there are more electrons
and a positive pole on the side where there are fewer elec-
trons, or more “empty holes” for electrons. To achieve this
electron flow, pure silicon must be treated to become a bet-
ter conductor. This is done by adding impurities, or other
elements, to the silicon, in a process called doping.
There are two layers of treated silicon in the solar cell.
Phosphorus is added to the first layer, resulting in an abun-
dance of free electrons. Because electrons have a negative
charge, this layer has a negative charge, and is thus called
n-type doped silicon. The other layer is doped with Boron,
resulting in an absence of electrons, or more holes for elec-
trons. This gives the layer an overall positive charge, and is
thus called p-type doped silicon (Figure 1).
The n-type silicon layer is positioned right next to the
p-type layer (Figure 2). All of the free extra electrons in the
n-type layer flow to fill up the holes in the p-type layer, creat-
ing an electric field. Right along the line where the two lay-
ers meet, something interesting happens: electrons are able
to move from the n-type layer into the p-type layer, but not
from the p-type layer into the n-type layer. This area where
the two layers meet is called the p-n junction. You can think
of it like a hill, where electrons can easily roll down the hill
(to the p-type layer) but it is very hard for them to go back
up the hill (to the n-type layer).
When the cell is exposed to light, the energy from
the light excites the electrons in the p-type layer, and they
break free from their holes (Figure 3). With contacts and
wires attached to conduct electrons out of the p-type layer,
through a load (such as a light bulb or motor), and back to
the n-type layer, we now have a complete solar cell circuit.
When an electron moves, the hole it was previously sitting
in becomes empty, and another electron can easily move
into its position (Figure 4). And because electrons can only
travel in one direction through the p-n junction, they must
pass through the wire and load to get back to the n-type
layer. This creates the electric current.
This basic solar cell with one p-type layer, one n-type
layer, and one p-n junction is called a first generation pho-
tovoltaic. A second generation photovoltaic has many layers
and multiple p-n junctions, to absorb more light. There is
also a third generation photovoltaic, which does not use the
traditional p-n junction at all.
This is a simplified description and we encourage you
to find out more about how solar cells work from books, the
internet, and your science teacher.
cover glass
antiglare layer
top contact layer
n-type silicon
p-type silicon
bottom contact layer
load
(motor)
electron flow
p-n junction
n-type layerp-type layern-type layerp-type layern-type layerp-type layer
photons (sunlight)
contact layer
contact layer
load
(motor)
electron flow
n-type layerp-type layer
sun
electron electron
hole free electron
sun
Diagram of the layering in
a modern solar cell
7

Powering an Engine
with the Energy of the Sun
The Solar Module
If you are going to be a solar engineer and make use
of the Sun’s energy, you first need a solar cell to con-
vert light into electricity. In your experiment kit, you
will find a small solar module (23) with several solar
cells. They are integrated into the black strips located
under the protective layer of plexiglass. If you turn the
module over, you can see the individual
cells quite clearly. Your module is just
like the big ones that you see on
the roofs of houses, except
that it is smaller and can’t
produce as much elec-
tricity.
Your experiment kit includes a battery holder (22)
onto which the solar module is mounted. In the bat-
tery holder, the electrical current is passed on to the
two sockets located on top of it on the left and right.
The electrical cables (20/21) are inserted into these
sockets. One cable is red, and the other is black. So
the battery holder has two functions: it serves as
something to attach the solar module to, as well as
something that connects the electrical cables to the
module. You can connect all kinds of electrical equip-
ment (the technical term is “electrical load”) — most
importantly, the motor — to these cables.
Your New Solar Engine
In our first experiment, we will use the Sun’s energy
to drive your kit’s engine and turn a small sprocket
wheel.
Experiment 1
> You will need: parts from the parts list (next
page, upper right)
Instructions
Insert the small gray engine shaft (19) with a small
sprocket wheel (9) mounted on it into the engine
(24). Secure the engine and the solar module (23)
with the battery holder (22) to the base plate (1),
as shown in the photo at the top of the next page.
Then connect the engine and battery holder with the
electrical cables (20/21). The red cable is the positive
The solar module (23)
In order to pass on the power of the Sun, each of your
module’s two brackets has a round metal conductor.
It is through these two terminals that the positive and
negative current produced by the solar cells becomes
usable.
The battery holder (22) isn’t just for mounting the module (23). The
cables that will supply the engine with electricity are also attached to it.
In most of the models, the small engine shaft (19) is inserted into the
solar engine (24) in order to transfer the engine’s power to the model.
8

Parts List
1 x base plate 1 1 x small sprocket wheel 9
1 x engine shaft 19 1 x black cable 20
1 x red cable 21 1 x battery holder 22
1 x solar module 23 1 x solar engine 24
line and the black one is the negative line. Be sure to
pay attention to the plus and minus symbols on the
battery holder and the engine when you attach the
cables. Then take your model into bright sunlight and
orient the module toward the Sun. What happens?
Results
As soon as enough light falls on the solar module,
the engine will start to turn. Direct sunlight is bright
enough to get your engine going. In shade, it isn’t
bright enough — the engine won’t move. Light and
shadow are like the on-off switch for the solar engine.
The solar cell has the ability to convert light into
electrical current, and it is this electrical current that
drives the engine. The engine stops when not enough
light falls on the solar module. In your house — of-
ten, even right next to the window — the light isn’t
intense enough. The bigger a solar cell is, the more
current it can produce. It also makes a difference how
the solar cell is constructed. On your module, there
are just a few small solar cells that are only capable
of producing a little current. That is why your engine
needs a lot of light in order to turn.
In our first experiment, a small sprocket wheel (9) mounted on the
engine shaft is turned. Mount it so that it sits flush at the front.
Your first solar model turns the small sprocket wheel inserted onto the
engine shaft.
Little Shadows
It would be interesting to know just how much light
your solar module needs in order to run the engine.
Experiment 2
> You will need: your solar model from the previ-
ous experiment
Instructions
Set your solar model in bright sunlight so that the
engine turns. Next, hold your finger over the solar
cell. Does the sprocket wheel still turn? What happens
when you hold two or more fingers over the solar
module? Try adjusting the distance between your
fingers and the solar module.
Results
When you hold your finger over the solar module, it
creates a small shadow. The shadow in turn darkens
a small part of the surface of the panel in which the
solar cells are located. The rest of the panel still gets
enough light to run the engine. The more of the panel
that you cover in shadow with your fingers or hand,
the less light the solar cells get. When there isn’t
enough light, the engine won’t move.
IMPORTANT NOTE ABOUT LIGHT SOURCES!
Not all light sources produce enough light for the solar cell to
power the motor. We recommend at least a 75 Watt incandescent
bulb in a suitable desk lamp fixture. Fluorescent lights, flashlights,
and low-voltage halogen lights will not work well. Of course, the
Sun is much more powerful than household lamps and should be
used if possible.
9

Your solar engine doesn’t only run in bright sunlight. It will also run on bright light from a lamp. Use a 75 Watt incandescent bulb in a desk lamp.
Artificial Clouds
You know the story: it’s a bright sunny day, then it
gets cloudy and the nice weather is over. You have to
go inside if the sky darkens with heavy black thunder-
clouds. And worst of all: your solar engine won’t work.
But why is it that the sunlight on an overcast day isn’t
enough to power the engine?
Experiment 3
> You will need: bright sunlight, your solar model,
a sheet of 8 1/2 x 11-inch transparent paper (white
tracing or wax paper)
Instructions
Hold the transparent paper over your solar module
while the engine is turning. Then fold the paper down
the middle and hold this smaller surface over the
solar cells. Fold the paper again and again, observing
what happens each time you hold it over the solar
module.
Results
When you hold the unfolded thin, transparent sheet
over the solar cell, enough light still gets through and
the engine still turns. When you fold it, the sunlight
has to get through another layer in order to reach the
solar cell. The more you fold the sheet, the more lay-
ers you create. Each layer absorbs some of the light.
When there are too many layers, there isn’t enough
light getting through to the cell and the engine stops.
When the sky gets overcast, the same thing hap-
pens. Layers of clouds come between the Sun and
the Earth. Enough light can still get through a thin
layer of cirrus clouds to power the solar model. But
not enough of the Sun’s rays can get to your model
through thicker layers of cloud cover.
Artificial Sun
As you know, light isn’t only produced by the Sun. A
lamp with an incandescent or halogen bulb can also
provide light. Will this kind of light also run your mo-
tor?
Experiment 4
> You will need: daylight, your solar model, an as-
sortment of lamps in your house
Instructions
On a bright sunny day, turn on several lamps in your
home, such as floor lamps, overhead lights, and desk
lamps. Hold your solar module directly under the
lamps. What happens?
Results
Your solar cells don’t just convert sunlight into electri-
cal current. If a lamp produces enough light, it can
also run the solar engine. In that sense, lamps work
just like an artificial Sun.
Not all of the lamps in your house will provide
enough light. The incandescent bulbs in electric lights
have different levels of strength. The strength of these
kinds of lights are indicated in watts (W). A bulb with
60 watts creates much brighter light than one with 15
watts. Also, some lights use a reflector to focus their
light, creating greater brightness at a specific point.
Reflectors are usually silver-colored.
There are some kinds of lighting that have built-in
reflectors as well as ones that concentrate light.
Because there are so many different kinds of lamps
and lighting, one might be bright enough to run the
engine while another might not.
10

Did you know . . .
. . . that there is a world championship for solar cars?
Every year, a solar car world championship is held in Australia. In the contest, the cars have to drive about 3,000 km
across the entire continent. The one that finishes first is the world champion. The fastest solar cars reach speeds of
over 100 km/h, driving on normal roads. During the race, the solar cars are accompanied by separate cars driven by
their team members. Most of the teams in the contest come from universities. Many of the electricians and mechan-
ics are students who take part in the race for fun. All the race cars are unique models, each one different from the next.
That means they are also very expensive. These solar race cars typically cost more than $300,000 to build.
The Artificial Sun’s Power
Why doesn’t the solar engine run in every part of your
home — even in a particularly bright room? The next
experiment should shed some light on this.
Experiment 5
> You will need: solar model and a light in your
house that is strong enough to move the solar engine
when you hold the engine directly beneath it
Instructions
Hold your solar model directly under the light that
is strong enough to run the engine. Then gradually
increase the distance between the lamp and solar
module. What happens?
Results
The farther away you get from the lamp, the less light
is emitted from it. You can see that particularly clearly
on a street at night, when a car drives toward you with
its headlights on. When the car is still far away, all you
see is two small points of light. But when it drives
by you, the light of the car is much, much brighter.
Because the brightness of a light source drops with
distance, the solar cell won’t get enough light to run
the motor when it is too far away.
Ambient Light
During the day, daylight enters your home. A term for
this kind of light is ambient light (literally meaning
“surrounding light”). In the next experiment, we will
see if ambient light has any effect on the solar cell.
Experiment 6
> You will need: solar model, a long ruler, a light
in your house that is strong enough to run the solar
engine when you hold the module directly beneath it.
A desk lamp works the best.
Instructions
In the middle of a sunny day, hold your model under a
light that is strong enough to run the engine. In-
crease the distance until the engine stops. There has
to be a lot of sunlight entering the room. Measure
the distance between the lamp and the model. Write
down the measurement. Repeat the experiment after
sundown and compare the distances measured. If
you don’t want to wait until evening, you can just shut
the blinds.
Results
During the day — even when the sky is overcast —
sunlight enters your house. The solar cell can make
The Honda Dream, a spectacular solar race car.
11

use of this light. Even when just a little enters in, it
can be used to produce electricity. But most of the
time, it will be too weak to start the engine. The more
light that reaches the solar cell, the more electricity it
produces. Starting at a certain level of brightness, the
cell will produce enough electricity to run the engine.
During the day, sunlight combines with the light from
the lamp. That is why the engine runs at a greater
distance from the lamp than in the evening. After the
Sun sets, there is no more daylight and the light from
the lamp has to run the solar engine by itself.
Reverse Movement
Up to now, your solar engine has only run in one
direction. Now we’ll find out how to make it run in
reverse.
Experiment 7
> You will need: your solar model
Instructions
Run your model in bright sunlight. Watch the direc-
tion that the small sprocket wheel turns. Then remove
both electric cables from either the engine or the bat-
tery holder and plug them back in, but this time in the
opposite sides. Hold your model in bright light again.
What happens?
Results
After you reverse the cables, the wheel turns in the
opposite direction. That is because electrical current
always flows in just one direction. The engine rotates
in the same direction that the current flows. The
direction of flow can be changed by reversing the cur-
rent supply — which is exactly what you do when you
switch the cables. It makes no difference whether you
switch them at the battery holder or the engine. The
direction of current flow is determined by the solar
cell. Remember what you read on page 7 about how
solar cells work?
If the solar module is turned around, the current flows in the opposite
direction. That makes the rotation direction of the engine change, too
(see the text on p. 13).
You can change the rotation direction of the engine by reversing the
connections of the cables to either the engine or the battery holder.
The rotation direction of the engine follows the direction of the flow
of current. The solar module producing the current determines its
direction of flow (see the text on p. 13).
12

Switching the Solar Module
If it is the solar module that determines the direction
of the flow of current, it should be possible to change
the rotation direction of the engine by mounting the
module the other way around.
Experiment 8
> You will need: your solar model
Instructions
Run your model in bright sunlight. Note the direction
of rotation of the sprocket wheel. Mount the solar
module the other way around on the battery holder.
What happens?
Results
When the module is turned around, the electricity
flows in the other direction, which makes the engine
run in the opposite direction as well. If you want to re-
verse the direction of movement of a model — wheth-
er to make a vehicle go forwards and backwards or to
wind a cord up or down — it is easiest just to mount
the module the other way around.
Battery Power
The Sun only shines in the day — so it can’t run your
engine at night. That is why the engine also runs on a
battery, so you can still perform your experiments.
Experiment 9
> You will need: your solar model, a 1.5-V AA bat-
tery
Instructions
Switch out your solar module for a 1.5-V AA battery.
When you insert it, pay attention to the plus and
minus signs. Watch what happens.
Results
The battery turns the motor and the wheel just as well
as the solar module. Of course, the engine doesn’t
stop when you change the lighting, as it does with
the solar module. If you want to shut off the engine,
you have two options: either remove the battery from
the holder or pull out one of the cables. It makes no
difference whether you remove the cable from the
engine or the battery holder.
You can also change the rotation direction of the
engine in exactly the same manner as when it is run-
ning by solar power — the engine runs in the oppo-
site direction when you reverse the orientation of the
battery. Or, of course, you can still switch the cables at
the battery holder or the engine.
Batteries cost money, get used up quickly and pollute
the environment. The Sun’s light, on the other hand,
is available in large quantities for free, and it doesn’t
pollute the environment. Therefore, whenever light
conditions permit, you should avoid using battery
power. It is only a solution of last resort. If you do use
batteries, it is best to use rechargeable ones, since
they are more environmentally friendly. Large solar
facilities, in fact, charge rechargeable batteries during
the day so that electricity is also available at night.
If the Sun isn’t shining, you can also run your engine with a battery.
This should only be done when absolutely necessary, though, and not
as a rule.
The battery holder with battery
13

Parts List
4 x long frames 2 1 x short frame 3
1 x short rod 4 2 x medium gear wheels 7
3 x small gear wheels 8 1 x small sprocket wheel 9
1 x medium sprocket 10 2 x long axle shafts 16
4 x tire wheels 15 1 x black cable 20
1 x engine shaft 19 1 x battery holder 22
1 x red cable 21 1 x solar engine 24
1 x solar module 23 8 x anchor pins 26
2 x shaft plugs 25
Your First Solar Vehicle
The solar tractor works with a gear drive. The small gear wheel on the
engine turns the rear axle.
Solar Tractor
Your new solar engine works particularly well for pow-
ering vehicles. The first one we will build is a tractor.
Experiment 10
> You will need: the parts from the parts list, artifi-
cial Sun
Instructions
Carefully study the tractor assembly instructions on
the following pages and follow them to assemble your
model. You will need all the parts in the list on the
left.
Be careful to connect the parts exactly as shown in the
pictures. It is particularly important to count the holes
in the rods and frames so you insert the anchor pins
in exactly the right ones. For the tractor to run well, all
the wheels have to be able to turn easily. After assem-
bling the axles and wheels, make sure that everything
has enough play (see page 5).
When you have finished assembling the tractor, hold
it under an artificial Sun, e.g. a desk lamp. Carefully
observe how the power of the engine is transmitted to
the other parts of your model.
Results
The small sprocket wheel mounted on the small en-
gine shaft drives the medium sprocket wheel on the
rear axle of the tractor. That turns the rear axle and
the large wheels attached to it. So the power of the
engine is transmitted through two sprocket wheels.
The teeth of both wheels are constructed so that they
mesh with each other precisely.
14

1 2
3
5
4
6
78
1. Insert the engine shaft (19) into the solar engine (24). The short end
of the shaft goes in the engine block. Then mount a small sprocket
wheel (9) on the shaft.
2. The solar engine is mounted on a long frame (2). The engine’s
anchor pins go in the second, fourth, and sixth holes from the right.
3. From the other side, attach a second long frame (2) to the engine.
Press both frames together firmly, so the assembly is stable.
4. The anchor pins on the long frames serve to attach another long
frame (2), which you mount vertically.
5. Another long frame serves to provide additional strength. This one is
set right on top of the two long frames with the engine.
6. Now we’ll prepare the axles. Take two long axle shafts (16) and insert
a small gear wheel (8) over the short end of each one.
7. Push the two axle shafts through the outer holes of the frames at the
bottom. The gear wheels should be on the side away from the engine
shaft.
8. Insert a small gear wheel (8) and a medium sprocket wheel (10) on
the other side. The teeth of the sprocket wheel should mesh with those
of the wheel on the engine.
15

910
11
12
13
+—
14 15
9. Now mount the first two tire wheels (15) on the axle shafts. The
wheels should sit flush with the end of the axle.
10. Now mount one tire wheel (15) on each of the axle shafts on the
other side of the model.
11. Align the wheels and axles as shown in the picture, and be sure that
the axles turn easily.
12. Mount a short rod (4) on the top of the long frame sticking up
straight in the rear.
13. The battery holder (22) with the solar module (23) goes on this short
rod. Pay attention to the “+/-“ signs.
14. Take a short frame (3) and insert 8 anchor pins (26) into it as shown
in the picture.
15. At the front, your model will get two ornamental “headlights.” Start
by inserting two shaft plugs (25) into the frame.
16

16
17
18
19
16. Next, attach the “headlights”: Mount two medium gear wheels (7)
on the shaft plugs.
17. Now mount this small frame at the front of the model. The end with
the red anchor pins goes on top.
18. Now attach the cables to the engine. The red cable (21) attaches to
the positive pole, the black one (20) to the negative pole.
19. When you attach them to the battery holder, make sure that the red
one goes to the positive side and the black one goes to the negative
side.
Under the Artificial Sun
In the next experiments, we will find out how strong
your engine is, and what kind of performance your
solar module can deliver.
Experiment 11
> You will need: your model, artificial Sun, smooth,
flat surface such as a table top
Instructions
Now place your tractor on a smooth, flat surface,
such as the top of a desk. Hold an artificial Sun
— e.g., a desk lamp — directly over the solar module.
Watch what the vehicle does.
Results
As soon as enough light strikes the solar module,
your tractor starts moving. When the tractor moves
beyond the cone of light, it stops: The solar module
isn’t getting enough light anymore.
Driving in Reverse
If you attached the cables correctly, your vehicle
moved forward. Now we’ll make it go backward.
Experiment 12
> You will need: your model, artificial Sun, smooth,
flat surface
Instructions
Remove the solar module from the battery holder
and mount it the other way around, as shown in the
pictures on the left half of page 12. Place the vehicle
under the artificial Sun and let it move.
Results
When you turn the solar module, the direction of the
flow of current is reversed as well. So now the tractor
drives backward.
Experiment 13
> You will need: your model, artificial Sun, smooth,
flat surface
Instructions
Now switch the cables at the battery holder or the
engine. What happens?
Results
Your tractor drives forward again. When the cables
were switched, the direction of current flow was
reversed yet again.
17

On a bumpy surface, little rocks or twigs can create obstacles for your
model. Unfortunately, its engine isn’t powerful enough to overcome
them.
On a smooth surface, your solar vehicle runs flawlessly. Of course, the
Sun has to be shining brightly enough.
A Drive in the Sunshine
In the next experiments, we will see how your tractor
drives in the sunlight.
Experiment 14
> You will need: your model, bright sunlight, the
back side of a large 11 x 17-inch pad of drawing paper
or other large, solid, smooth piece of cardboard
Instructions
Lay a pad of drawing paper with its back side up, or
some other smooth, strong cardboard, in bright sun-
light. Orient the module toward the Sun. Be sure that
the cardboard is lying flat. Then let your solar tractor
drive on it.
Results
As soon as enough sunlight hits the solar module,
the engine starts to run, which turns the axles and the
wheels. The power of the sunlight is enough to run
your tractor on a smooth, even surface — your tractor
is running on solar power.
A Drive on Bumpy Ground
Up to now, you have only run your vehicle on a
smooth surface — the back side of the drawing pad.
Now we’ll see how it does on a bumpy surface.
Experiment 15
> You will need: bright sunlight, solar model, level
but bumpy ground (e.g. a level gravel path or a lawn
that isn’t too steep)
Instructions
Let your solar tractor run in bright sunlight on a
bumpy surface. Make sure that it isn’t going uphill or
downhill. How does it perform now?
Results
Your tractor either won’t start correctly or won’t move
at all. As soon as the tires hit any little obstacle, you
have to give the model a push to get it moving again.
The engine isn’t powerful enough to overcome these
little obstacles. The solar cells simply produce too lit-
tle electricity to drive the tractor over level but bumpy
ground. The same goes for all of the model vehicles
in this experiment kit. In order to get the models to
run well on bumpy ground, you would need much
larger and more powerful solar cells. But they would
be very costly.
A Downhill Drive
You know from riding a bicycle that you have to use
much less energy to go downhill. Does the same ap-
ply to your solar vehicle? You will find out in an experi-
ment on an “inclined plane.” An inclined plane is a
firm, flat surface that can be used to make a downhill
slope.
Experiment 16
> You will need: light, solar model, large drawing
pad or other strong cardboard
Instructions
Let your solar tractor drive down the inclined plane.
Use the back side of a drawing pad, lifting the end of
18