Solar+Energy

=Solar Energy Overview= toc The Solar Energy Module consists of four investigations that allow students to experience solar energy first hand and to investigate the variables that affect solar-energy transfer.

Objectives:

 * 1) become aware of the potential of solar energy, an inexhaustible source, as an alternative energy source to fossil fuels, a nonrenewable resource
 * 2) observe differences in size and position of shadows as a result of the relative positions of Earth and the Sun
 * 3) gain experience using a compass to orient objects on Earth
 * 4) become proficient in using a thermometer to monitor temperature change in a variety of materials
 * 5) observe solar-energy transfer in a variety of situations
 * 6) relate the rate and amount of temperature change to variables involved in energy transfer
 * 7) design solar water heaters and passive solar spaces heaters
 * 8) apply mathematics in the context of science
 * 9) acquire vocabulary associated with solar energy and energy transfer
 * 10) use scientific thinking processes to conduct investigations and build explanations: observing, communicating, comparing, organizing, and relating

Vocabulary List Audio Podcasts of Solar Energy Stories

Investigation 1

 * Light travels in a straight line.
 * Shadows are the dark areas that result when light is blocked by an opaque object.
 * The length of a shadow depends on the position and orientation of Earth relative to the Sun.
 * The lengths of shadows on Earth change as the Sun's position in the sky changes during the day due to the Earth's rotation.

Investigation 2

 * Change of energy from one form to another or from one object to another is called energy transfer. The law of conservation of energy states that energy can not be created or destroyed, only changed from one form to another.
 * Energy from the Sun is absorbed and released by different materials at different rates.
 * A heat sink is a material, such as water, that can absorb a large amount of heat for its volume and release the energy slowly.
 * A thermometer is a tool that can be used to measure the temperature (amount of heat) of a solid, liquid, or gas.

Investigation 3

 * The color of the collector in a solar water heater affects the change in water temperature.
 * Placing a clear cover on a solar water heater affects the change in water temperature.
 * The surface area of the collector in a solar water heater affects the change in water temperature.

Investigation 4

 * Change of energy from one form to another or movement of energy from one object to another is called energy transfer.
 * A heat sink is a material, such as water, that can absorb a large amount of heat for its volume and release the energy slowly.
 * Insulation can be used in a solar house to maintain its inside temperature.
 * Space heating is the transfer of heat energy to air in an enclosed space.

How do shadows form?
You can watch the effects of the sun's movement around the earth by observing shadows throughout a day. A shadow occurs when an opaque (not able to be seen through) object blocks light from the sun or other light source. Observing the behavior of shadows is an easy way to investigate some of the properties of light.

In the morning, just as the sun rises in the East, the shadow is long and points towards the West. The shadow shortens until the sun reaches it's highest point in the sky. As the sun travels on it's journey West, the shadow lengthens and steadily swings farther and farther East.

As the year passes and the seasons change, so does the sun's path in the sky. During December in the Northern Hemisphere the path of the sun is not very high In the sky. The shadows made in winter are the longest shadows you will see all year.

Points to understand include:
 * Light travels in straight lines
 * A shadow of an object will move due to either the motion of the object or of the light source
 * Even seemingly transparent objects can form shadows if they absorb or reflect some of the light striking them.

What is a Compass Rose?
The compass rose has appeared on charts and maps since the 1300's when the portolan charts first made their appearance. The term "rose" comes from the figure's compass points resembling the petals of the well-known flower.

A compass always points to the north and can be used to determine direction.

How does the sun move?
In ancient times, as people watched the sun move across the sky each day, they thought that the sun traveled around the earth. Scientists later found out that the sun remains in one place while the earth and the other planets travel around it. But we know now that the sun moves too!

The sun is just one star in a huge group of stars called a galaxy. Our galaxy, called the Milky Way, is spinning around like a phonograph record. And the sun is traveling around the center of the galaxy at a speed of about 481,000 miles per hour. At that speed, the sun will travel around the center of the Milky Way once in about 225 million years.

The Milky Way itself is moving around the center of a group of galaxies, like a planet moving around the sun. And this group of galaxies may be traveling around the center of the universe. So the sun is really moving in two or three directions at once!

Like the sun, all other stars are traveling through space at high speeds, but they’re so far away that to us, they look like they never move! solar eclipse interactive: http://teacher.scholastic.com/activities/science/moon_interactives.htm

Day and night happen because the Earth rotates once on its axis every twenty-four hours. Day occurs when our side of the Earth faces the Sun and night occurs when our part faces away. As the day progresses, the Sun appears to follow a path from its rising in the east to its setting in the west. Important points to understand include:

The Sun appears to move across the sky due to the rotation of the Earth about its axis.The Sun's path for a certain day is determined by the location of the observer on the Earth.Shadows that form in the morning and late afternoon will be longer than the shadows that form at noon. As you move closed to a light source, shadows get shorter in length. As you move further away from a light source, shadows get longer in length.

Heating the Earth
The sun has produced energy for billions of years. Solar energy is the sun’s rays (solar radiation) that reach the Earth. This energy can be converted into other forms of energy, such as heat and electricity. Energy from the sun is //free//. It's also //clean//, meaning it causes no pollution. Since the sun gives off more energy than we would ever need, it's //renewable//. It will never run out.

The sun radiates it solar energy into space in all directions. A very small amount of this solar energy reaches the Earth. About 90% of the energy reaching the surface of the Earth is visible light energy that we can see and infrared energy that we can feel when it hits our bodies or objects that we touch. Earth's surface (land and water) absorbs about one half of this energy, Earth's atmosphere absorbs about one sixth and the remaining one third of the energy is reflected back into space.

When an object absorbs light, the object becomes warmer. In the process light energy transforms into heat energy. This energy transfer changes the temperature of the material. http://www.wisc-online.com/Objects/ViewObject.aspx?ID=SCE304 Some of the energy that is absorbed by Earth is re-radiated from the surface as infrared radiation (heat energy). The water vapor and gases in the Earth's atmosphere trap some of the re-radiated heat and helps to maintain a fairly uniform global temperature.

Often the concepts of heat and temperature are thought to be the same, but they are not.Perhaps the reason the two are usually and incorrectly thought to be the same is because as human beings on Earth our everyday experience leads us to notice that when you add heat to something, say like putting a pot of water on the stove, then the temperature of that something goes up. More heat, more temperature - they must be the same, right? Turns out, though, this is not true.

The atoms and molecules in a gas are in constant motion. Temperature is a measure of the speed with which they move. (More exactly it is a measure of their .) The higher the temperature, the faster the molecules move.

The surface of our planet is about three-fourths water and one-fourth rock. The solid earth materials that make up the continents absorb the Sun's energy differently than water. Land surfaces heat up more quickly when exposed to solar energy and reach higher temperatures than water surfaces. During the night, when the earth's surface is not being subjected to solar energy, land surfaces cool off more quickly and reach much lower temperatures than water surfaces. The difference in the amount of solar radiation absorbed by land and by water results in temperature differentials that influence the movement of air masses, a powerful force affecting global weather.

There are a number of reasons for the temperature differences between land and water. More heat is required to warm a volume of water than to warm an equal volume of water than to warm an equal volume of almost any other substance. Water requires five times as much heat energy as solid rock to rise the same number of degrees.

A heat sink is any cool mass that can absorb excess heat, including bodies of water, the ground, and massive building materials. Water is a very good heat sink because it has a big capacity to absorb and store energy. It is a particularly effective heat sing because it releases energy slowly when the energy source disappears. Other reasons for the temperature differences between land and water include: These differences between land and water have interesting effects on climate. Coastal cities enjoy a moderate climate, usually without temperature extremes. Inland cities experience a greater range of temperatures through the seasons.
 * land is opaque, water is transparent. Solar radiation can penetrate water so the hear is distributed to a greater depth than on land.
 * land is solid while water is usually liquid. Heat moves slowly though rock by conduction and quickly through water by mixing.
 * some of the solar energy absorbed by water is lost during evaporation.

How is solar energy used?
When converted to **thermal (or heat) energy**, solar energy can be used to:
 * Heat water — for use in homes, buildings, or swimming pools
 * Heat spaces — inside homes, greenhouses, and other buildings
 * Heat fluids — to high temperatures to operate a turbine to generate electricity

Solar energy can be converted to electricity in two ways:
 * **Photovoltaic (PV devices) or “solar cells”**change sunlight directly into electricity. Individual PV cells are grouped into panels and arrays of panels that can be used in a wide range of applications ranging from single small cells that charge calculator and watch batteries, to systems that power single homes, to large power plants covering many acres.
 * **Solar Thermal/Electric Power Plants** generate electricity by concentrating solar energy to heat a fluid and produce steam that is used to power a generator. In 2009, there were 13 solar thermal-power generating units operating in the United States, 11 in California, 1 in Arizona, and 1 in Nevada.

The main benefits of solar energy are: Two limitations of solar energy are:
 * Solar energy systems do not produce air pollutants or carbon-dioxide
 * When located on buildings, they have minimal impact on the environment
 * The amount of sunlight that arrives at the Earth's surface is not constant. It varies depending on location, time of day, time of year, and weather conditions.
 * Because the sun doesn't deliver that much energy to any one place at any one time, a large surface area is required to collect the energy at a useful rate.

Although it's not a perfect analogy, you can think of the Earth sort of like your car sitting out in a parking lot on a sunny day. You've probably noticed that your car is always much hotter inside than the outside temperature if it's been sitting there for a while. The sun's rays enter through your car's windows. Some of the heat from the sun is absorbed by the seats, the dashboard and the carpeting and floor mats. When those objects release this heat, it doesn't all get out through the windows. Some is reflected back in. The heat radiated by the seats is a different wavelength than the light of the sun that made it through the windows in the first place. So a certain amount of energy is going in, and less energy is going out. The result is a gradual increase in the temperature inside your car.

What is the greenhouse effect?
A greenhouse is a house made of glass. It has glass walls and a glass roof. People grow tomatoes and flowers and other plants in them. A greenhouse stays warm inside, even during winter. Sunlight shines in and warms the plants and air inside. But the heat is trapped by the glass and can't escape. So during the daylight hours, it gets warmer and warmer inside a greenhouse, and stays pretty warm at night too.

Earth's atmosphere does the same thing as the greenhouse. Gases in the atmosphere such as carbon dioxide do what the roof of a greenhouse does. During the day, the Sun shines through the atmosphere. Earth's surface warms up in the sunlight. At night, Earth's surface cools, releasing the heat back into the air. But some of the heat is trapped by the greenhouse gases in the atmosphere. That's what keeps our Earth a warm and cozy 59 degrees Fahrenheit, on average. If the greenhouse effect is too strong, Earth gets warmer and warmer.

What blocks the Sun’s energy from escaping from the Earth? Unlike a greenhouse, the Earth does not have a layer of glass over it! Instead, molecules in our atmosphere called greenhouse gasses absorb the heat. Greenhouse gasses include water vapor, methane, ozone, nitrous oxide, and carbon dioxide. There may not be much of some of these gasses in our atmosphere, but they can have a big impact. Each greenhouse gas molecule is made of three or more atoms that are bonded loosely together. These molecules are able to absorb heat, which makes them vibrate. They eventually release the heat energy and it is often absorbed by another greenhouse gas molecule.

The greenhouse effect is useful because trapping some energy keeps the temperatures on our planet mild and suitable for living things. Without its atmosphere and the greenhouse effect, the average temperature at the surface of the Earth would be zero degrees Fahrenheit. However, too many greenhouse gases can cause the temperature to increase out of control. Such is the case on Venus where greenhouse gases are abundant and the average temperature at the surface is more than 855 degrees Fahrenheit (457 degrees Celsius).

Calendar
Create a Wordle || media type="custom" key="10351422" || early dismissal ||  || summary table 1 summary table 2 summary table 3 summary table 4 summary table 5 summary table 6 summary table 7 ||  || audio: http://www.fossweb.com/modules3-6/SolarEnergy/audio_stories/audio_stories.html || Tree Shadow Puzzle || || (Two group's data and graph of earth materials) || || 1. this wiki calendar 2. the class notebook 3. edline calendar || || || || HW: Investigation 3 Part 1 || media type="custom" key="11087124" || Solar Power from the Wind || || Investigations 3 and 4 ||  ||
 * September 1 ||  || finished scientist drawing ||   ||
 * September 2 ||  || CW: Traits of a scientist ||   ||
 * September 5 ||  || No School ||   ||
 * September 6 ||  || CW: What is a Scientist
 * September 6 ||  || CW: What is a Scientist
 * September 7 ||  || CW: The Nature of Science
 * September 8 ||  || no school ||   ||
 * September 9 ||  || no school || media type="custom" key="10351420" ||
 * September 13 ||  || CW: The Nature of Science
 * September 13 ||  || CW: The Nature of Science
 * September 13 ||  || CW: The Nature of Science
 * September 14 ||  || CW: Shadows ||   ||
 * September 15 ||  || CW: Shadow Play || media type="custom" key="10471850" ||
 * September 16 ||  || CW: Guided Reading || The Sun
 * September 19 ||  || CW: Shadow Tracking || [[file:shadow tracker.pdf]] ||
 * September 20 ||  || no science due to 4 sight testing ||   ||
 * September 21 ||  || CW: Sun Tracking || [[file:student response sun tracking.pdf]] ||
 * September 22 ||  || CW: Sun Tracking ||   ||
 * September 23 ||  || CW: Problem of the Week || [[file:math extension invest 1.pdf]] ||
 * September 26 ||  || CW: Thermometer in the Sun and Shade || [[file:thermometer in the sun and shade.pdf]] ||
 * September 27 ||  || CW: i check quiz ||   ||
 * September 28 ||  || Notes: Thermometer || media type="custom" key="10647150" ||
 * September 29 ||  || No school ||   ||
 * September 30 ||  || CW: Review quiz ||   ||
 * October 3 ||  || CW: Guided Reading - differential heating || [[file:differntial heating story.docx]] ||
 * October 4 ||  || Earth Materials in the sun and shade
 * October 3 ||  || CW: Guided Reading - differential heating || [[file:differntial heating story.docx]] ||
 * October 4 ||  || Earth Materials in the sun and shade
 * October 4 ||  || Earth Materials in the sun and shade
 * October 5 ||  || CW: Wrap Up
 * October 6 ||  || CW: Investigation 2 Heating the Earth Big Ideas || [[file:Investigation 2 Heating the Earth Summary Big Ideas.docx]] ||
 * October 7 ||  || CW: Response Sheet - Heating the Earth || [[file:response sheet heating the earth.pdf]] ||
 * October 10 ||  || CW: Study guide || [[file:2 Heating the Earth Study Guide.docx]] ||
 * October 11 ||  || ICheck Quiz ||   ||
 * October 12 ||  || Notebook test || This is an open book test that verifies that students have the necessary papers in their notebooks and that they are correcting our classwork as we go along. Students can not study for this test but they can be prepared by checking their notebooks against
 * October 12 ||  || Notebook test || This is an open book test that verifies that students have the necessary papers in their notebooks and that they are correcting our classwork as we go along. Students can not study for this test but they can be prepared by checking their notebooks against
 * October 13 ||  || Parent conferences ||   ||
 * October 14 ||  || No school for students - teacher inservice day ||   ||
 * October 17 ||  || CW: review for test || [[file:Investigations 1 and 2 Study Guide.docx]] ||
 * October 18 ||  || Unit Test - Investigations 1 and 2 ||   ||
 * October 19 ||  || Alternative Energy Project || [[file:Intermediate Energy Infobook.pdf]]
 * October 19 ||  || Alternative Energy Project || [[file:Intermediate Energy Infobook.pdf]]
 * October 20 ||  || Work on Project ||   ||
 * October 21 ||  || Work on Project ||   ||
 * October 24 ||  || Work on presentation ||   ||
 * October 25 ||  || finish presentations ||   ||
 * October 26 ||  || Presentations ||   ||
 * October 27 ||  || Presentations ||   ||
 * October 28 ||  || Guided Reading: Predicting Weather ||   ||
 * October 31 ||  || CW: Solar Water Heaters and The Nature of Light || [[file:solar water heater.pdf]]
 * October 31 ||  || CW: Solar Water Heaters and The Nature of Light || [[file:solar water heater.pdf]]
 * October 31 ||  || CW: Solar Water Heaters and The Nature of Light || [[file:solar water heater.pdf]]
 * November 1 ||  || CW: Class chart and solar energy graph || [[file:solar energy graph.pdf]]
 * November 2 ||  || Notes: Solar Water Heater
 * November 3 ||  || Guided Reading: Solar Technology || [[file:Guided Reading Solar Techonology.docx]] ||
 * November 4 ||  || Lab: Surface Area Effect || [[file:math extension invest 3.pdf]] ||
 * November 7 ||  || Graph results || [[file:solar energy graph.pdf]] ||
 * November 8 ||  || Study Guide || [[file:3 Solar Water Heater Study Guide.docx]] ||
 * November 9 ||  || I Check 3 quiz ||   ||
 * November 10 ||  || Review Quiz ||   ||
 * November 11 ||  || Solar Heating Orientation || [[file:space heating.pdf]] ||
 * November 14 ||  || graph results || [[file:solar energy graph.pdf]] ||
 * November 15 ||  || Solar Energy Color || [[file:space heating.pdf]] ||
 * November 16 ||  || graph results
 * November 15 ||  || Solar Energy Color || [[file:space heating.pdf]] ||
 * November 16 ||  || graph results
 * November 17 ||  || study guide || [[file:4 Solar Heating Study Guide.docx]] ||
 * November 18 ||  || I Check 4 Quiz ||   ||
 * November 21 ||  || Study Guide || [[file:5 Solar Energy Unit Study Guide.docx]] ||
 * November 22 ||  || Notebook Test ||   ||
 * November 23 ||  || Unit Test