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Solar energy.

What Is Solar Energy?

The Sun is a star, the center of our solar system (so-lar sys-tem). The Sun appears larger than other stars because it is closest to Earth. The distance between Earth and the Sun is about 150 million kilometers.

Like other stars, the Sun is made of boiling gases called hydrogen (hy-dro-gen) and helium (he-li-um). The gases are so hot, they make the Sun glow. The temperature at the center of the Sun, or the core, is 27 million degrees Fahrenheit. The Sun's energy or solar energy (so-lar en-er-gy) comes from deep inside its core.

The scorching heat causes constant movement of hydrogen atoms. Some of the atoms (at-ores) stick together in a process called nuclear fusion (nu-cle-ar fu-sion). Fusion changes hydrogen into helium and creates energy. Solar energy is then released as heat and light.

Why Is the Sun important?

Life on Earth would not exist without the Sun. Sunlight provides enough solar energy to warm our planet and to support all plant, animal, and human life. The Sun controls the amount of daylight around the world. It also controls the four seasons on different parts of the Earth as it orbits (or-bits) the Sun.

The Sun's light is the source of all our food. Plants need the Sun to make food for themselves in a process called photosynthesis (pho-to-syn-the-sis). The part of a plant that makes it green--the chlorophyll (chlo-ro-phyll)--uses sunlight to build nutritious sugar molecules (mol-e-cules) from water and carbon dioxide (car-bon di-ox-ide). Some of the sugar is used immediately for growth; the rest is stored for later. Animals and humans then eat these nutritious plants.

Humans rely on plants and animals--all supported by solar energy. Reptiles are cold-blooded, and need the Sun's heat to warm their bodies so they can move, hunt, and escape predators. We still use many fuels that come from plants, such as oil, gas, and coal.

Solar energy is a valuable resource for supplying power. Some people use solar power to light and heat homes, cook food, and run appliances, such as refrigerators and computers.

Why Study the Sun?

Today, most power used in the United States is produced from oil, natural gas, and coal. Oil and gas are already in short supply. In just a thousand years, much of our planet's supply of coal has already been mined. It is possible we could run out of these non-renewable (non-re-new-able) fuels someday. They are being used faster than they can be replaced. Even if they could last forever, they create pollution (pol-lu-tion).

Renewable (re-new-able) sources include sunlight, water, and wind. The Sun provides a constant source of energy, but solar energy stations take up a lot of space; and they only make power when the Sun is shining. Solar technology is also expensive.

Scientists use solar probes and telescopes to learn about the Sun. They examine solar cells and develop shiny plastic films to use for solar panels. Solar energy stations can be made to work even when there is no sunlight.

One day, if more ways to harness solar energy are found, it may help us have a brighter future.

DID YOU KNOW??

Never look straight at the sun, even with sunglasses, it will burn your eyes.

Vocabulary

Match each "Sun" word with its definition.

1. central, hottest part of the sun

2. to convert or change into a vapor

3. the work a system is capable of doing

4. a mixture, blend, or combination which creates energy

5. of or having to do with the sun

6. not able to restore or make new again

7. to revolve

fusion

solar

energy

orbit

non-renewable

evaporate

core

Weekly Lab

Let's make a solar oven to make nachos. What kinds of materials do you think you'll need to build a cooker that melts cheese? Make sure your oven has an absorber (ab-sorb-er--to hold in the heat), a reflector (re-flec-tor--to reflect sunlight), and a transmitter (trans-mit-ter--to allow light through). Use solar energy to make a warm snack.

Science Says ...

Insulation (In-sul-a-tion) helps hold heat inside the oven.

You need: paper (white, black and colors), pencil, notebook, scissors, tape, watch or timer, assorted boxes, deli containers with lids, aluminum foil, plastic wrap or tortilla chips, cheese slices

Day One

Step 1: As a group, plan and sketch your oven.

Step 2: Select a box and other materials.

Step 3: Build a solar oven. Place a thermometer on the bottom of it. What do you predict will be the most important part of your oven?

Day Two

Step 4: On the blacktop, place chips and cheese in the oven.

Step 5: Record your observation and the temperature every 5 minutes.

Step 6: After 45 minutes, look at other ovens and compare how well each one worked. Discuss why.

Math

How much electric energy does a family use in a day? Ask a parent to show you the electric meter at home and help you read it. kwh is a unit of measure which means kilowatt (kilo-watt)--hours, or 1,000 watts per hour.

1. Write down today's meter reading,--kWh units

2. Read the meter again 24 hours later.--kWh units

3. Subtract the first number from the second =--units used in a day

4. How much does electricity cost? Use the sample reading to figure it out.

Sample reading: Sat. 10:00 a.m. 7,899 kWh units

Sun. 10:00 a.m. 7,928 kWh units

7,928-7,899 =--units used in a day

5. If a unit costs 12 cents, these units will cost:

Writing In Science

In your journal, or on a separate sheet of paper, write a paragraph describing why your oven cooked well or why it did not. Did you use the right materials? Which construction technique in your class resulted in the fastest-cooked snack? Explain why. How did solar energy work to help you complete your task today?

DID YOU KNOW??

The Sun's corona is an area of thin gas which extends millions of miles from the Sun. It'S heated by magnetic energy from the sun. Corona means "crown."

Also, draw a picture of your solar oven. Label the absorbers, reflectors, and transmitters.

Challenge

Renewable sources of energy never run out. If we use sunlight all day long, the Sun will still shine tomorrow. Non-renewable sources run out.

Directions: Find five, different renewable sources in a row. Color in your answer.
SOLAR BINGO

SOLAR COAL OIL DIESEL WOOD
POWER FUEL

WIND GASOLINE PROPANE WATER OIL
POWER GAS POWER

WOOD DIESEL HAY AND PROPANE WATER
 FUEL OATS GAS POWER

COAL WIND WOOD GASOLINE POWER
 POWER

SOLAR HAY AND DIESEL COAL WIND
POWER OATS FUEL POWER


Puzzle

Unscramble these solar words. Write the letters in the red boxes in the same order in the boxes at the bottom to find out what the secret phrase is. (Hint: the answer is Spanish for "hot sun".) (1)

Spanish for "hot sun" is sol ardoroso

DID YOU KNOW??

Solar flares are eruptions of gas and energy from parts of the Sun's photosphere, or surface layer, that have sun spots (spots on the surface). There are more solar flares when there are more sunspots.
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Publication:Science Weekly
Date:Mar 27, 2006
Words:1193
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