Margaret Bell Miller
Middle School
Technology Education Department
Solar Energy
&
battery Energy
Mr. Torbic
Mr. Wingrove
©
Spring 2002
TABLE OF CONTENTS
|
CONTENT |
PAGE
|
|
SOLAR ENERGY IN THE
PAST
|
2 |
|
SOLAR ENERGY DEFINED
|
3-5 |
|
EXAMPLES OF SOLAR
ENERGY
|
5 |
|
BATTERY ENERGY
|
6-7 |
|
ELECTRICAL TERMS
|
8-13 |
|
LAB EQUIPMENT
|
14-15 |
|
EQUIPMENT HANDLING
|
15-17 |
|
ACTIVITY # 1 Wire
Leads
|
18-19 |
|
ACTIVITY # 2
Resistance
|
20-21 |
|
ACTIVITY # 3 Voltage
|
22-26 |
|
ACTIVITY # 4 Amps
|
27-31 |
|
GLOSSARY
|
32-34 |
|
STANDARDS AND
OBJECTIVES
|
35-36 |
|
WEB REFERENCES
|
36 |
|
quiz
|
37 |
sOLAR ENERGY IN THE PAST
The time is around 212 B.C. and the Roman naval fleet is making a charge on
the shores of Syracuse. It is a sunny day and a Greek genius is
attempting to defeat the strong roman navy with an idea most think to be
crazy. The genius, Archimedes, uses large mirrors to reflect the suns
rays toward the ships causing the wooden ships to burn and sink. The
idea works and the Romans do not invade Syracuse.
The most simple and inexpensive approach for obtaining energy in the form of
heat from the sun’s rays was developed in the middle of the eighteenth century
by Nicholas De Saussre. His design of a solar oven could reach
temperatures up to 150 degrees. The oven consisted of glass plates,
chemically coated, on top of an insulated box with a black surface. The
sunlight would pass through the glass and be absorbed by the black surface.
In 1839, a French scientist named Edmund Becquerel observed that light,
falling on certain materials, produced
electricity.
The amount of electricity varied with the amount and intensity of light.
Scientists made solar cells of selenium in the 1880s. Modern solar cell
technologies were developed at Bell Labs and RCA Labs in the mid 1950s.
Solar Energy Defined
The previous three examples are early forms of solar energy. Solar
energy is energy given off by the sun in the form of heat and light.
Flat-plate solar collectors collect this energy. There are
three basic types of collectors.
The liquid (hydronic) type has water running in tubes inside the
collector plate. The plate is angled in the suns rays and uses the heat
of the sun to heat the water in the tubes for use in the home.
The next type is known as air type. Airways, known as baffles,
are located inside the collectors. When the suns rays hit the collectors
the air is heated and distributed throughout the home. Even on those
cold winter days the suns rays can still heat the air in the baffles helping
to lower the running time of the furnace.
The
type most commonly known to the classroom student is the solar, or
silicon type. Solar cells have no moving parts. Power is
produced when sunlight strikes the semiconductor material and creates an
electric current. Solar cells are used to power remote residences, satellites,
highway signs, water pumps, communication stations, navigation buoys,
streetlights and calculators. The type known as photovoltaic cells
are wafer thin and are lightweight, relatively low in power (.5 volts), but
are a good source of long term power for operating satellites. In this
class, we will use the solar panel, or the photovoltaic cell. The photovoltaic
cell consists of a single silicon chip. The solar panel is several solar
cells wired together in a collector and the photovoltaic cell.
PHOTOVOLTAIC CELL
SOLAR PANEL
Photovoltaic System
What Are Solar Cells?
- Thin wafers of
silicon.
- Similar to computer
chips
- Much bigger
- Much cheaper
- Silicon is abundant
(sand)
- Non toxic and safe
- Light carries energy
into cell.
- Cell converts light
energy into electric energy.
- Sunlight is the fuel.
Flat-plate
collector
Battery Energy
The
next step in the evolution of electrical energy storage was the invention of
the lead acid storage battery in 1859 by the French physicist Gaston Plante.
This chemical battery used a liquid electrolyte, and was not easy to move.
This situation changed with the development of the dry cell battery, which was
based on the pioneering work done between 1867 and 1877 by Georges Leclanche
in France. In the dry cell battery, the electrolyte is a damp paste so that
there is no liquid to leak out, and thus quite portable. Thomas Alva Edison
developed the alkaline storage battery, in common use today, in 1914. It is so
called because the electrolyte has an alkaline base, rather than acidic base.
Like the electrolyte in a dry cell, it is not a liquid, so it can be easily
transported.
Batteries
are widely used as sources of direct-current electrical energy in automobiles,
boats, aircraft, ships, portable electric/electronic equipment, and lighting
equipment. In some instances, they are used as the only source of power; while
in others, they are used as a secondary or standby power source.
A battery consists of a number of cells assembled in a common container and
connected together to function as a source of electrical power. A
cell is a device that transforms chemical energy into electrical energy
The types of batteries most commonly used today are the dry cell and the wet
cell. The
dry cell
battery is used in items such as cameras, flashlights, toys, and other small
portable devices. It contains a
direct current,
unlike the outlets and switches in most homes, which contain
alternating current.
The
polarity
of the
cathode
is positive, and the polarity of the
anode
is negative. The
wet cell
is more for the larger machines like cars, boats, and heavy machinery.
DRY CELL
WET CELL
ELECTRICAL TERMS
VOLTS
Electromotive force
(Voltage). Electromotive (electron-moving) force or voltage is
electrical potential, which provides energy for the movement of electrons in a
circuit.
This electrical potential results from a difference in electron energies at
two points in a circuit. This difference in electron energy levels in a
circuit can be compared to the potential energy of water stored in a high
water tower and the kinetic energy of water flowing through the pipe.
Voltage
is measured in units called
volts
(a difference variable) and is abbreviated with the letter symbols
V.
Compared to a water system, a volt would be similar to a measure of water
pressure in a pipe, such as pounds per square inch.
Amperage
Electron flow (Amperage). An electric current is a flow of electrons
along a conductor. The speed of this flow is nearly equal to
the speed of light, 186,000 miles per second. The number of electrons that
pass a point in a wire in one second measures the flow of electricity. An
ampere is a measure of electron flow; it represents a flow of 1 coulomb of
electricity (6 billion electrons) past a point in a wire in one second. Amps
are the unit that measures current. It is abbreviated by the capital
letter I. Compared to a water system, an ampere would be similar
to a measure of water flow through a pipe, such as gallons per minute.
RESISTANCE
Resistance to current flow (Resistance). Resistance is the
ability of a material to resist electron flow. Materials vary in their
number of valence electrons and in the ease with which electrons may be
transferred between atoms. A conductor is a material through which
electrons can flow freely. An insulator is a material that provides
great resistance to electron flow. Electrical Resistivity is measured
in units called ohms. The symbol for resistance is R, and the
symbol for ohms is the Greek letter omega (Ω). Measuring for
continuity is measuring for the ability for electrons to flow.
Ohm's Law
The physicist, George Simon Ohm, discovered that the flow of electrical
current through a conductor is directly proportional to the electromotive
force that produces it and inversely proportional to the resistance in the
conductor. If the resistance to electron flow through an electrical device is
cut in half, the current amperage doubles. If the resistance remains constant,
but the voltage is doubled, the current amperage will double. This
relationship is expressed in Ohm's law as
E = IR.
I
equals current in amperes.
E
equals potential energy in volts.
R
equals resistance in ohms.
IN SIMPLE TERMS
If you
had a tank of water with a valve at the bottom and a water line extending from
the valve, the tank of water would be the potential force (volts) that would
pass or move through the valve when opened (amps), and the size of the pipe or
anything inside of the pipe would decide the flow rate (resistance).
When
using a photovoltaic panel or cell the sun is the potential force (volts) and
the flow of free electrons from the cell/panel to the load is the current
(amps). The resistance would be clouds or rain if you’re outside, but if
your inside it could be the brightness of the light.
The water tank is like a battery holding the force of pressure. The
valve is the switch that controls the flow of water. The pipe is the
path in which the flow of water travels, but is restricted to that path. In an
electrical circuit, the battery holds the potential force. The amps are
the flow of that force past a given point in time. The resistance or
ohms is anything that slows or restricts the flow.
Series/paralleL circuits
When
components are
connected one following another in a ring, the components are said to be in
series with each other and the circuit is called a series circuit.
+ --
Single Source Series Circuit
2 Source’s In
Series Circuit
When
components are connected between a ring of electricity they are connected in
parallel. The voltage is the same for each load in the circuit.
This type of wiring allows for more than one path for electricity to travel.
2 Source’s In A
Parallel Circuit
Lab equipment
MULTI-METERS
PHOTOVOLTAIC CELL
SOLAR PANEL
DRY CELL BATTERIES
MOTOR (LOAD)
Proper handling and storage
To ensure that
future classes will have the same chance for completing this activity, you
must handle and store the lab equipment in a correct manor.
1.
First make sure you carry the equipment in the palm of your hands.
2.
Do not carry the meters or panels by the wires.
3.
Be sure to change the leads of the meter by pulling at the throat of
the lead.
4.
Store the wires of the meter wrapped around the meter as shown in the
picture.
5.
Store the meters and panels in the cabinet in a safe and respectful
manor.
6.
Never force the equipment into the drawer. If it doesn’t fit do
not force it.
7.
Never poke or jab anyone with the leads or alligator clips of the
wires.
8.
Never run with the equipment in your hands.
Look at the pictures for further support of the rules.
Place the cells and motors
neatly
Remove and return the
in the drawer.
equipment with care.
Carry
the solar panel in the palm
Return the meters with wires wrapped
of your hands.
and place in the drawer as shown.
Wrap
wires and carry carefully.
Remove the wire by the end, not
by the wire.
Do not
carry
the panels by the wires.
Activity #1 Making wire leads
Background
In this activity, you will make two separate wire leads with alligator clips
to use in the remaining activities. These leads will be used to make the
necessary connection from the source to load, and to the meter.
Each group member will make a lead from the wire provided by the teacher.
The members of the group will be responsible for their leads throughout the
wiring activities.
Materials/ tools:
·
Wire (2
pieces about 12 inches long)
·
Alligator
clips (4)
·
Straight
head screwdriver
Procedures:
1.
Using the wire strippers set in the proper gauge, strip away about ½
inch of insulation exposing the bare wire.
2.
Slide the clip cover onto the wire.
3.
Loosen the holding screw on the alligator clip and slide the bare wire
into the barrel of the alligator clip.
4.
Tighten the holding screw to secure the wire to the alligator clip.
5.
Slide the clip cover over the clip barrel and repeat process for the
other side of the wire.
Activity #2 rESISTANCE
Background
When
learning to use the multi-meters the important thing to remember is to never
have the source or power supply on or in the circuit when measuring ohms.
Never test solar cells, batteries, or electrical outlets for resistance.
The reason for this is because the meters have fuses in them and if a
power supply is applied to the meter it could blow the fuse. In this
activity you will be measuring the continuity of different materials to decide
if they are conductors (material that will carry the flow of electrons
easily), or if they are insulators (things that resist the flow of electrons).
Materials
·
Paper clip
·
Coin
·
Stick
·
Multi-meter
Activity #2 Measuring Resistance In Materials
Worksheet
Objective for Activity #2
·
Use the ohms
setting for measuring resistance of the material (look at picture below).
·
Using the
multi-meter place the red and black probes from the meter on different sides
of the material and record the reading on a separate piece of paper.
·
A reading of
0.00 - .30 means the material has little resistance and it is a conductor.
·
Readings of
1.00 means that the material resists flow and is an insulator.
Never test solar cells,
batteries, or electrical outlets for resistance.
|
Material |
Reading |
Insulator |
Conductor |
|
Paperclip |
|
|
|
|
Coin |
|
|
|
|
Stick |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
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|
|
|
aCTIVITY #3 VOLTAGE
Background
In this
activity, you will measure the voltage of three sources: the solar
photovoltaic panel, the photovoltaic cell, and several different batteries.
All three sources will be measured as a single source, 2 sources in series,
and 2 sources in parallel.
By the completion of this activity you will be able to see through the meter
readings that each source has voltage available for a circuit. The
results discovered in the single source and the parallel sources should be
similar in measurement. The series voltage reading will show how the
voltage is added when wiring in series.
On page #23 & #24 are drawings for the proper placement of the meter leads to
the source. These drawings will also show the proper wiring of sources
in series and parallel.
On page #24 are the photos of the meters used in this class, set for measuring
voltage. Take notice of the placement of the leads on the meter, and be
sure your meter matches the one in the photo.
Measuring Voltage Of A Single Source
Measuring Voltage
Of 2 Source’s In Series
Measuring Voltage
Of 2 Source’s In Parallel
VOLT
SETTING
aCTIVITY #3 VOLTAGE Worksheet
Materials
·
Meter
·
Wires with
alligator clips
·
2 solar
panels
·
2
photovoltaic cells
·
Batteries (2
of the same size)
·
Contacts
Objective for Activity #3
Using the table below,
measure the voltages of the different sources and record the meter reading.
The photovoltaic cell, and the solar panel, will need to have a reading inside
the classroom and outside in the sunshine.
|
Source |
Single |
Series |
Parallel |
|
Cell inside |
|
|
|
|
Cell outside |
|
|
|
|
Panel inside |
|
|
|
|
Panel outside |
|
|
|
|
“D” Size Battery |
|
|
|
|
“C” Size Battery |
|
|
|
|
“AA” Size Battery |
|
|
|
|
“AAA” Size Battery |
|
|
|
|
“9 Volt” Battery |
|
|
|
Which
of the sources produced the highest voltage? ____________________
Will
the voltage increase with a series or a parallel reading? ______________
Do
your readings for the batteries match your classmates? ______________
If not, why? _______________________________________________
How
did the inside readings compare to the outside readings? ____________
__________________________________________________________________________________________________________________________
measuring voltage in series circuits without a load
measuring voltage in a parallel circuit without load
Activity #4 amperage
Background
In this
activity, you will measure the amperage (amps) of a circuit using three
different sources: the photovoltaic panel, the photovoltaic cell, and several
different batteries. All three sources will be wired in circuits as a
single source, 2 sources in series, and 2 sources in parallel.
By the completion of this activity, you will see, through the meter readings,
the flow of electrons through the circuit. The results found from
measuring a single source and the series sources should be similar in size.
The parallel circuit should reveal an increase in amps.
This activity also finalizes and combines all of the information about
resistance, voltage, and amperage. Being able to measure and read these
aspects of a circuit will help in determining the proper amount of volts, or
amps, along with resistance, through the use of ohms law (E= I x R).
Page #28 & #29 have the drawings for proper placement of the meter in the
circuit. Page #29 has the proper setting of the leads on the meter.
Measuring Amps In A Single Source Series Circuit
Measuring Amps In A
2 Source Series Circuit
Measuring Amps In A
2 Source Parallel Circuit
AMP SETTING
aCTIVITY #4 Amperage Worksheet
Materials
·
Meter
·
Wires with
alligator clips
·
2 solar
panels
·
2
photovoltaic cells
·
Batteries (2
of the same size)
·
Contacts
Objective for Activity #2
Using the table below,
measure the amps of the different circuits and record the meter reading.
The photovoltaic cell, and the solar panel, will need to have a reading inside
the classroom and outside in the sunshine.
|
Source |
Single |
Series |
Parallel |
|
Cell inside |
|
|
|
|
Cell outside |
|
|
|
|
Panel inside |
|
|
|
|
Panel outside |
|
|
|
|
“D” Size Battery |
|
|
|
|
“C” Size Battery |
|
|
|
|
“AA” Size Battery |
|
|
|
|
“AAA” Size Battery |
|
|
|
|
“9 Volt” Battery |
|
|
|
Which
of the sources produced the highest amps? ____________________
Will
the amps increase with a series or a parallel reading? ______________
Do
your readings for the battery circuits match your classmates? __________
If not, why? _______________________________________________
How
did the inside readings compare to the outside readings? ____________
__________________________________________________________________________________________________________________________
Glossary
Alternating Current (AC)
Electrical energy, which alternates
cyclically between positive and negative in polarity. In many countries,
including the U.S., the polarity reversal is made to occur 60 times per second
(60 hertz). The current travels in two directions.
Ampere (I)
Unit of measurement of electric flow, or
current, like volume of water in a stream. A count of how many electrons pass
a given point in one second. A closed circuit is necessary for current flow.
Named after Andre Ampere, the French mathematician and physicist who
quantified electric flow around about the year 1820.
Anode
The positive terminal of an electrolytic cell
or battery.
Battery
A group of interconnected
electrochemical cells. Single cells are considered to be a battery if they are
used alone. A battery cell contains an anode, a cathode, and the electrolyte.
The nominal voltage of a lead-acid cell is 2 volts.
Cathode
The negative terminal in an electrolytic cell
or battery.
Cell
A device that transforms chemical energy into
electrical energy.
Circuit
A continuous path allowing and directing the
flow of electric current.
Conductor
A material that electrons can flow through
freely.
Direct Current(DC)
Electrical energy that does not cyclically
alternate in polarity: e.g. electrical energy from a battery or solar cell.
The electricity flows in one direction.
Dry Cell
A closed container, usually a can, made of
zinc with a carbon rod in the center surrounded with a wet part containing
ammonium chloride with particles of manganese dioxide and powdered carbon
Electrical Resistivity
The resistance of the flow of electricity
through material. Measured in ohms.
Electricity
The movement of electrons through a
conductor. In conductors, such as gold, copper, and aluminum electrons
can be easily forced to break orbit and flow to a new orbit around at a
neighboring atom. Each electron leaving an atom is replaced by another
in a musical chairs like dance. Electrons can only flow in a closed
circuit.
Electromotive Force (emf)
The force that causes electrons to flow
because of a difference in electrical potential (measured in volts).
Electron
A negatively charged particle, which orbits
the positively charged nucleus of an atom. Electrons have 1/1837 the mass of
hydrogen (the lightest atom ), therefore electrons are subatomic!
Energy
The capacity to do work.
Flat Plate
A photovoltaic surface installed to face
south at a tilt angle equal to the latitude.
Hydro
A prefix meaning produced by or derived from
water or the movement of water, as in "hydroelectricity".
Insulator
Any material through which electric current
will not flow.
Load
The part of the system that supplies the
voltage and current that causes the sparks or discharges between the electrode
and work piece. It is usually housed in a cabinet separate from the machine
tool and connected to it by a cable.
OHMS
Unit of measure for resistance.
Parallel
A connection between cells or batteries (also
PV's) to increase the current capacity. The voltage stays the same when we
wire positive to positive and negative to negative, but the capacity in
battery amp-hrs is the sum of the batteries wired in parallel.
Photovoltaic (PV)
Pertaining to the production of electricity
from light.
Polarity
The designation of positive (+) or negative
(-) electrical potential to the electrode.
Resistance Opposition to the flow of current
Unit of measurement is called an Ohm, stated
as R, or by the Greek letter omega. All conductors have some resistance, this
is necessary because if a conductor had no resistance the connection would be
a short circuit with excessive current flow. Insulators have high resistance
and conductors have low resistance. Bad connections ( loose, corroded, or
dirty ) have high resistance and can result in little current flow.
Series
A connection from one cell or battery to
another (or from one PV module to another), negative to positive, which
results in twice the voltage. Note that the current stays the same when series
interconnecting.
Solar Cell
Device made of semiconductor materials, which
produces a voltage when exposed to light.
Solar Electricity
Electricity produced directly by action of
sunlight.
Solar Energy
Generating electrical energy from solar light
by means of solar cells.
Solar Panel
A group of modules combined on a mounting
structure. May be wired in series for increased voltage, or in parallel for
increased current, or a combination called series-parallel.
Valance Electrons
The outer most electrons of an atom that
transfers from atom to atom creating the flow of electricity.
Voltage
Electric potential.
Volts ( V )
The electromotive force, which will cause
current to flow. A standard definition of the volt is: an emf of 1 Volt is
necessary to move a current of 1 Amp through a 1-Ohm resistor. A voltmeter
measures the difference in potential between two points. It may be helpful to
think of voltage to electricity flow as pressure is to water flow.
Voltmeter
An instrument that measures voltage.
Wet Cell
A zinc and a copper pole placed in a liquid.
Used in car batteries.
PENNSYVANIA STATE STANDARDS
Academic Standards
for Science and Technology
3.1.7B. Describe the use
of models as an application of scientific or
technological concepts.
3.1.7C. Identify patterns
as repeated processes or recurring elements in
Science and technology.
3.1.7E. Identify change as
a variable in describing natural and physical
systems.
3.2.7B. Apply process
knowledge to make and interpret observations.
3.2.7C. Identify and use
the elements of scientific inquiry to solve
problems.
3.4.7B. Relate energy
sources and transfers to heat and temperature.
3.7.7A. Describe the safe
and appropriate use of tools, materials and
techniques to answer questions and solve problems.
3.7.7B. Use appropriate
instruments and apparatus to study materials.
3.8.7A. Explain how
sciences and technologies are limited in their
effects and influences on society.
3.8.7C. Identify the pros
and cons of applying technological and
scientific solutions to address problems and the effect upon
society.
OBJECTIVES
1.
Explain systems by outlining a
system’s relevant parts and its purpose and/or designing a model that
illustrates its function.
2.
Identify and describe patterns
that occur in physical systems (e.g., construction, manufacturing,
transportation), informational systems and biochemical-related systems.
3.
Describe the effect of making a change in one part of a system on the
system as a whole.
4.
Interpret data, formulate models, design models, and produce solutions.
5.
Conduct a two-part experiment.
6.
Explain the conversion of one form of energy to another by applying
knowledge of each form of energy.
7.
Describe safe procedures for using tools and materials.
8.
Apply knowledge of different measurement systems to measure and record
objects’ properties.
9.
Identify changes in society as a result of a technological development.
10.
Describe ways technology
extends and enhances human abilities.
Web Resources
Brain Pop
www.brainpop.com
Solar Information Links
www.solarexpert.com/
About Photovoltaic
www.eren.doe.gov/pv/
Photovoltaic video
www.eren.doe.gov
Kid Safe Web Site
http://www.kidgrid.com/
Solar energy site with
links to pictures of many different types of
Photovoltaic
installations
http://www.epsea.org
Name
______________________________________
Date _____________
Technology Education
Mr. Wingrove
SOLAR ENERGY AND
BATTERY ENERGY QUIZ
Sunlight
Series
Insulator
Cathode Average
Resistance
Anode Amps (Ampere)
Voltage Parallel
Conductor
Photons
Increases
- The potential or
pressure in an electric source is known as _____________.
2.
The solar panel and photovoltaic cell produce electricity from
__________.
3.
_____________ is the opposition to current flow and is measured in
ohms.
4.
Testing for continuity will tell you if a material will pass electrons
(___________), or resist the flow of electrons (___________).
5.
An electric circuit that has only one path for the electricity to
travel is a _____________ circuit.
6.
The positive (+) end of a battery is known as the _____________, and
the negative (-) end is known as the _____________.
7.
An electric circuit that has several paths for electricity to travel on
is known as a _____________ circuit.
8.
The flow electrons or current of in an electrical circuit is measured
in ___________.
9.
In a series circuit the voltage ______________, and in a parallel
circuit the voltage is the __________ of the sources.
10.
The sun sends out _____________, which push electrons from the valence
electron shell into the circuit creating electricity in a photovoltaic cell.
11.
– 14. Draw a series circuit on the back
of the paper that contains a: battery, switch,
load, and pathway. Label the positive and negative poles of the battery.
MBM
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