Thames & Kosmos Solar Mechanics User manual

EXPERIMENT MANUAL

GENERAL ADVICE AND WARNINGS
. Please read these instructions, follow the safety rules,
and keep them for reference. We recommend you build the
models in the order given. You will then be able to under-
stand the way the parts connect together, and go on to cre-
ate many more different models.
. This kit has been designed for children over  years of age.
It aims to help children discover solar power and how it
works while creating a variety of models.
. Discuss the safety warnings and possible risks involved
with the children before allowing them to build these
models.
. In order to prevent a short circuit and damage to the solar
motor unit, do not expose the solar panel to a high tempera-
ture light bulb for a long period of time.
. While activating the solar powered models with a light
bulb, please keep your hands away from the light bulb and
fixture to avoid burning yourself.
. Please experiment with at least a  watt light bulb or out-
door sunshine. A normal electric flashlight is too weak to ac-
tivate the solar vehicles.
SAFETY ADVICE

IMPORTANT INFORMATION
WARNING! Not appropriate for use by
children under  years of age. There is a
danger of suffocation due to the possibili-
ty of swallowing or inhaling small parts.
The kit contains some small parts, such as
anchor pins, gears, and axles, so it is abso-
lutely essential that you keep it out of the
reach of young children.
Save the packaging and instructions, as
they contain important information.
Dear Parents,
Solar power is an exciting, cutting-edge
technology, and it isn’t really all that
hard to understand. This kit makes the
science of solar power — generating
electricity from light — tangible and
fun for young scientists.
This experiment kit is designed to help
bring the fascinating world of mechan-
ics and solar power a little bit closer to
your child. With its multipurpose mate-
rials and easy-to-grasp examples, it will
provide a first look into the world of
physical measurements and laws —
and thus also contribute to a better un-
derstanding of what your child will be
learning in school.
The individual experimental setups are
assembled step by step out of pieces
with variably interconnecting parts.
The assembly will take a little patience
and practice at first. It will be ideal if
you can help your child until he or she is
familiar with all the connection
methods.
We wish your child a lot of fun discover-
ing and learning!


EQUIPMENT
✔No. Name Qty.
 Large frame 
 Square frame 
 Long rod 
 -hole rod 
 -hole dual rod 
 -hole flat rod 
 -hole rod 
  degree converter - L 
  degree converter - R 
 Shaft pin 
 Joint pin 
 Anchor pin 
 Axle lock 
 -hole flat rod 
 Curved elbow rod 
 Part separator tool 
 Small gear wheel 
 Medium gear wheel 
 Large gear wheel 
 Long axle 
 Medium axle 
 Short axle 
 Motor axle 
 Wheel ( mm) 
 . Volt Solar Motor Unit 
Total 
If you are missing
any parts, please
contact Thames &
Kosmos customer
service.
Any materials not
contained in the kit
are marked in italic
script in the “You will
need” boxes.
Checklist: Find – Inspect – Check off
Additional things
you will need:
sunlight, desk lamp with incandes-
cent bulb, fluorescent lighting, in-
dex card, wooden blocks, tape mea-
sure or yard stick, chalk or tape,
stopwatch or timer, plank of wood


Powering Up: Solar Cells
Pages 9 to 24
Learn how solar cells convert
sunlight into electricity, and
how to use that electricity
✔
You will find supplemental
information on pages ,  to
,  to , and .
CHECK IT OUT
Gearing Up:
Transmissions
Pages 4 to 9
How to move mechanical
energy from one place to
another
The Models: Part 1
Pages 25 to 38
Assemble solar powered
vehicles
The Models: Part 2
Pages 39 to 56
Assemble other solar
powered devices and
machines

CONTENTS

Transmissions allow you to move mechanical energy from
one place to another. Your solar-powered models will depend
heavily on transmissions to make their wheels and other
components work. In this section, you will learn how the
gears are used to make transmissions that either increase
the speed of a wheel or increase the turning force of a wheel.
Gearing Up:
TRANSMISSIONS


HERES HOW
. Assemble the parts as shown.
. Slowly turn gear A one time around ex-
actly, which is called one rotation. Care-
fully observe gear B as you do this.
How many times does gear B turn for
each full rotation of gear A?
. Now slowly rotate gear B around once.
Observe gear A as you do this.
How many times does gear A turn for
each full rotation of gear B?
Gear test 1
YOU WILL NEED
→  parts from the kit:
For each rotation of gear A, gear B ro-
tates three times. Gear A has  teeth
and gear B has  teeth. Thus, after the
gears have meshed  teeth together,
the small gear has already spun around
once, while the large gear has only made
it a third of the way around. For each ro-
tation of gear B, gear A turns a third of a
rotation.
Gear B spins faster at its center than
gear A. So you see, gears can be used to
change rotational speeds.
→WHATS HAPPENING
B
A
 Teeth
 Teeth
2
1
X1
X1 10
X1
19 17
X1
X1
22
X2
Which of these four locations for the
red gear will allow it to turn when the
yellow gear turns?
A B
C D
EXPERIMENT 1
Gearing Up: Transmissions | 

HERES HOW
. Assemble the parts as shown to the
right.
. Before you do anything else, make a
prediction:
When you turn the big yellow gear clock-
wise (as indicated by the blue arrow
above), in which direction will the small
red gear turn?
. Now turn the gear and test your
hypothesis.
Gear test 2
YOU WILL NEED
→  parts from the kit:
A B
A B
問題：
問題：
A B
A B
問題：
問題：
A B
A B
問題：
問題：
2
1
X1
X1 10
X1
19 17
X1
X1
22
X2
The red gear turns counterclockwise
when the yellow gear is turned clock-
wise. Gears that mesh with each other
change the direction of rotation. So, not
only can gear trains — series of inter-
locking gears — be used to change the
speed of a gear, they can also be used to
change the direction a gear is spinning.
→WHATS HAPPENING
Answer B: The red gear turns
clockwise.
Answer A: The red gear turns
counterclockwise.

EXPERIMENT 

HERES HOW
. Assemble the parts as shown on the
right.
. Now make a prediction.
When you turn the small red gear to the
left, in which directions will the medium
blue gear and large yellow gear turn?
. Now turn the gear and test your
hypothesis.
Gear test 3
YOU WILL NEED
→  parts from the kit:
A B
A B
問題：
問題：
A B
A B
問題：
問題：
A B
A B
問題：
問題：
The blue gear turns clockwise and the
yellow gear turns counterclockwise. So,
the yellow gear is actually spinning in
the same direction as the starting red
gear, because the direction has been
changed twice. Has the gear train accom-
plished any change then? To answer
that, observe the speed of the yellow
gear in relation to the red gear.
→WHATS HAPPENING
Answer B: The blue gear turns clock-
wise and the yellow gear turns
counterclockwise.
Answer A: The blue gear turns coun-
terclockwise and the yellow gear
turns clockwise.
2
1
X1
X1 10
X2
19
17
X1
X1
22
X2
21
18
X1
X1
Gearing Up: Transmissions | 
EXPERIMENT 

HERES HOW
. Assemble the parts as shown.
. Now make your prediction:
When you turn the yellow gear clock-
wise, in which direction will the blue
gear turn?
Gear test 4
YOU WILL NEED
→  parts from the kit:
The blue gear will turn clockwise. The
gear train turned a corner! Here you see
that these gears can be positioned at
right angles from one another, changing
the plane of motion.
→WHATS HAPPENING
2
1
X1
X1
10
X2
19
17
X1
X1
22
X2
21
18
X1
X1
5
X4
Answer B: counterclockwiseAnswer A: clockwise
Gear Ratio =
Number of teeth
on driven gear
Number of teeth
on driver gear

EXPERIMENT 

MACHINES
For something to be called a machine, it has to have
a source of power and a way to transmit power from
one place to another — a transmission. Power can
come from many sources, like heat or electricity.
Power can be transmitted in many ways. Gear trains
like the ones you have just experimented with in Ex-
periments – are good examples.
This kit contains a special machine called the solar
motor unit. It is a single-piece device that takes light
and converts it into motion. The light source can be
sunlight or even light from a powerful lamp. The mo-
tion is the spinning of an axle that sticks out from ei-
ther side of the unit.
But how exactly does the solar motor unit convert
light into motion? The solar panel on the top — a se-
ries of photovoltaic panels — generates electric cur-
rent when exposed to enough light. That electric cur-
rent in turn goes to powering an electric motor,
which results in the spinning of the motor’s shaft.
From there, a transmission consisting of four gears
carries the motion all the way to the axles on the
sides of the unit, which can be used to activate your
models!
The solar panel and the electric motor will be ex-
plained in the next section. First, let’s look at how
the transmission in the solar motor unit works.
INCREASING
TORQUE
In Experiment , your gear
train had a gear ratio of :.
For every one rotation of the
large yellow driver gear, the
small red driven gear rotated
three times.
Inside the solar motor unit,
the opposite happens. A se-
ries of four gears takes a fast-
spinning motor shaft and re-
duces the speed.
But why would you want to
slow it down? The answer is
simple: when you reduce the
speed of an output gear in a
gear train, you increase the
torque of the output gear.
Torque is a measure of the
turning force of a rotating ob-
ject. In this case, you can
think of it as the strength of a
gear to turn another gear.
So, by decreasing the speed,
the solar motor unit has in-
creased the strength of the
motor to turn gears and axles
and power your vehicles and
devices!

teeth
 teeth
 teeth
 teeth
Gear Ratio =
Number of teeth
on driven gear
Number of teeth
on driver gear
CHECK IT OUT
Gearing Up: Transmissions | 

To make the motor run, you need electricity
supplied by the solar panel. In this chapter, you
will conduct a series of experiments with a test
car that will teach you how the solar panel
works and under what conditions it works best.
Powering Up:
SOLAR CELLS


HERES HOW
. Assemble all the parts as shown,
following each picture step by step.
Build your
test car
YOU WILL NEED
→  parts from the kit:
22
25
24
2322
20
18
17
12
8
7
5
4
X2 X1 X1 X2
X3 X2 X1
X1
X1 X1 X4 X1
TIP
To remove anchor pins, use the
part separator tool as a lever!



→ → → → →
Powering Up: Solar Cells | 
EXPERIMENT 

23
20
Build your
test car
The model
will run
better with a
 mm gap
between the
gear and
frame.




You assembled a simple test vehicle with
which you can now conduct a number of
experiments to learn about putting solar
power to work!
→WHATS HAPPENING

EXPERIMENT 

HERES HOW
Test how well your solar motor unit
powers your model car in the following
light conditions.
. Outside on a sunny day, with the sun
high in the sky.
. Outside on a cloudy or overcast day
. Inside under a desk lamp with an incan-
descent bulb ( watts or greater
recommended).
. Inside under fluorescent lighting, such
as long fluorescent tubes or compact
fluorescent bulbs.
Under which light source does the mod-
el run the fastest along the ground?
Which light sources do not provide
enough energy to run the motor at all?
What do you notice about the relation-
ship between the intensity of the light
and the speed of the motor?
Light sources
YOU WILL NEED
→ test car model
→ a sunny day
→ an overcast day
→ desk lamp with
incandescent bulb
→ fluorescent lighting




Sunlight on a sunny day should power
the motor to run the fastest. An incan-
descent bulb will also run the motor, if
the lamp is close enough to the solar
panel. Even though a fluorescent bulb
appears very bright to us, it does not
emit the amount of light energy needed
to run the motor. A cloudy day however
may actually provide enough sunlight to
power the motor — the sun is that
powerful!
→WHATS HAPPENING
Powering Up: Solar Cells | 
EXPERIMENT 

HERES HOW
. Put the test car outside in the sunlight
or under a desk lamp so that the motor
is running.
. With a small card, such as an index card,
cover a third of the solar panel’s surface
area and note the speed of the motor.
. Cover half of the solar panel’s surface
area and again note the speed.
. Cover two-thirds of the solar panel.
Does the motor still run?
Testing different
light levels
YOU WILL NEED
→ test car model
→ a sunny day or a desk lamp
with incandescent bulb
→ small card (e.g. index card)
The surface area of a solar panel is di-
rectly proportional to the electrical pow-
er output. Assuming the same light con-
ditions, the larger your solar panel, the
more electricity it will generate.
→WHATS HAPPENING

EXPERIMENT 

HERES HOW
. Take the test car outside on a sunny
day and prop it up on a block of
wood so it doesn’t roll away.
. Using different blocks, position
the car so that the solar
panel sits at different
angles relative to the
sun.
What orientation
of the solar panel makes
the motor run the fastest?
Optimum tilt of
the solar panel
YOU WILL NEED
→ test car model
→ a sunny day, when the sun is
high in the sky
→ small blocks of wood
The motor runs the fastest when the so-
lar panel is most directly facing the sun.
Because the sun is so far away, its rays
hit Earth virtually parallel to one anoth-
er. When the solar panel’s surface is di-
rectly facing the sun, the light rays hit it
perpendicularly. When the solar panel’s
surface is tilted at an angle to the sun,
the light rays hit it at an angle. The more
perpendicular the angle is, the more en-
ergy per surface area there is. See page
 to learn more about this.
→WHATS HAPPENING
Powering Up: Solar Cells | 
EXPERIMENT 

A solar cell is a flat device that uses an elec-
tronic material called a semiconductor to
convert photons, or particles of light ener-
gy, into electrical energy. The semiconduc-
tor creates a voltage, or difference in elec-
trical 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 technology
is called photovoltaics.
The phenomenon of electricity is nothing
more than the movement of negatively
charged particles, called electrons, through
a material, called a conductor. Electricity
flows easily 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 conductors under
special conditions. These are called
semiconductors.
load
(motor)
electron flow
p-n junction
n-type layer
p-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
1. Two layers of silicon
There are two layers of treated silicon in
the solar cell. Phosphorus is added to the
first layer, resulting in an abundance of
free electrons. Because electrons have a
negative charge, this layer has a negative
charge, and is thus called n-type doped sil-
icon. The other layer is doped with Boron,
resulting in an absence of electrons, or
more holes for electrons. This gives the
layer an overall positive charge, and is
thus called p-type doped silicon.
2. The layers come together
The n-type silicon layer is positioned right
next to the p-type layer. All of the free ex-
tra electrons in the n-type layer flow to fill
up the holes in the p-type layer, creating
an electric field. Right along the line where
the two layers meet, something
load
(motor)
electron flow
p-n junction
n-type layerp-type layer
n-type layer
p-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
How Does a Solar Cell Work?
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 electrons, or more “empty holes” for electrons. To achieve this electron flow, pure sil-
icon must be treated to become a better conductor. This is done by adding impurities, or
other elements, to the silicon, in a process called doping.


→ →


load
(motor)
electron flow
p-n junction
n-type layerp-type layern-type layerp-type layer
n-type layer
p-type layer
photons (sunlight)
contact layer
contact layer
load
(motor)
electron flow
n-type layerp-type layer
sun
electron electron
hole free electron
sun
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 layer
p-type layer
sun
electron electron
hole free electron
sun
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).
cover glass
antiglare layer
top contact layer
n-type silicon
p-type silicon
bottom contact layer


→ →
third generation photovoltaic,
which does not use the tradi-
tional 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.
3. Let there be light
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.
With contacts and wires at-
tached 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.
4. The electrons flow
When an electron moves, the
hole it was previously sitting
in becomes empty, and anoth-
er electron can easily move
into its position. 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 photovolta-
ic. A second generation photo-
voltaic has many layers and
multiple p-n junctions, to ab-
sorb more light. There is also a
CHECK IT OUT
Powering Up: Solar Cells | 

HERES HOW
. With your tape measure or yard stick,
measure a distance along the smooth,
flat ground and mark the start and end
points with chalk or a piece of tape. For
our example, we will choose three feet.
But you can experiment with different
distances.
. Using the stopwatch or timer, time how
long it takes the test car to travel be-
tween the start and end points. Record
the time.
Time trials
YOU WILL NEED
→ test car model
→ tape measure or yard stick
→ chalk or tape
→ stopwatch or timer
→ area of smooth, flat ground
outside on a sunny day
Distance (D)
Test car A
→ → → → →

EXPERIMENT 