How can you get the most heat energy from the sun?

How can you get the most heat energy from the sun?

Materials needed

• · Three identical jars
• · Paper and pencil
• · Black paper
• · Aluminum foil
• · Tape
• · Three thermometers
• · Sand

Procedure

1. Fill the three jars with sand.

2. Cover one jar with black paper, including the top,and tape the paper in place.

3. Cover the second jar with aluminium foil, including the top, and the tape the foil in place.

4. Leave the third jar uncovered.

5. Record the temperature shown on the thermometers. Be sure all three indicate the same temperature.

6. Insert one thermometer into the sand in each jar. With the two covered jars, puncture a hole in the top covering and insert the thermometer through the hole.

7. Place all three jars in sunlight. All should receive the same direct sunlight.

8. Check and record the temperature of the three thermometers every 15 minutes for about two hours.

9. How o the temperatures compare? What can you say about the effect of a black surface and a shiny surface on absorption of energy from the sun?

10. Remove the jars from the sunlight and continue to record the temperature of the three thermometers for two more hours.

Questions. How do the temperature changes compare? What can you say about the effect of a black surface and a shiny surface on heat loss?

For problems solvers

 here are more ways to compare the effect of color on heat absorption. Place a thermometer on a paper plate and lay a sheet of black paper over it.

Prepare a second plate using a thermometer and white paper, then a third using aluminum foil. On a warm, sunny day day, place all three plates in direct sunlight. Check and record the temperatures on the thermometers on the thermometers after one-half hour, then again after one hour.

If you live in a cold climate, place papers of various color on snow bank, in the sunlight.use a black paper, a white paper and a piece of aluminum foil of the same size. Use other colors also if you’d like to. Line them up, so the all have direct sunlight. After an hour, check the snow under the papers to find out how much has melted. Check them again after two hours.

Hydro Power Experiment

Warming up with wheels: Why were wheels so important in history? What can one do better with a wheel? Play with wheels and write down 5-10 things that wheels can help you do. The pictures below can give you a hint or two.

Introduction:

For thousands of years people have used the pushing power of water to drive machines. Early wheeled vehicles were pushed or pulled by people and animals. Since Roman times wooden waterwheels have powered millstones to grind corn. Later, waterwheels became the main power source for industry. The modern day water turbine was developed from the waterwheel.

All waterwheels direct water around wheel blades to start the wheel spinning. Water creates its own pressure due to its weight. Energy from fast-flowing water turns a waterwheel. The constant movement from the revolving wheel can then be put to work. You can harness the work from your water wheel to raise a bucketful of water.

Materials:

    small (590-ml) plastic soda bottle
    large (2-L) plastic soda bottle
    scissors
    straw
    hammer and punch
    toothpicks
    pencil
    tape
    large screw-type bottle cap
    glue
    0.5 meters of kite string
    sink with running water
    small weights
    paper towels (just in case!)


Classroom Management:

Students should build their water wheels in small groups of 3-5 students. Teachers may wish to have stations with materials already cut for student construction. If it is too difficult to obtain the materials, one waterwheel can be made for demonstration to the entire class.


Activity Steps:

Imagine talking to people on top of a mesa who are tired of bringing up water from the stream at the foot of the mesa. They want you to design a way to save them the trip. The first step is to design and build a water wheel that will life water out of a stream and dump water into a bucket. Later you will have a chance to design a system of lifting water up to the mesa dwellers. Make a drawing of your water wheel.


Design challenge : Power of a Waterwheel
Cut out the bottom of a small plastic soda bottle. Cut out five evenly-spaced flaps around the sides of the bottle and fold them as shown.

Hydro Power Experiment

An adult should punch a hole in the bottom of the waterwheel with a punch and hammer. Insert a straw through the hole so that it freely rotates.

Cut the side of the large plastic soda bottle large enough to place the waterwheel inside. Place two holes on either side of the soda bottle for the straw to pass through.

Hydro Power Experiment

Place the waterwheel inside the bottom of the large soda bottle. Carefully ease the straws through the holes and secure with toothpicks.

Make two holes in the top of the large soda bottle and insert the pencil. Tape a short piece of straw under the end of the pencil.
Make a bucket from the bottle cap. Glue a matchstick across the top. Tie it to around a 0.5 meter of string. Feed the string through the short piece of straw on the pencil and tie it to the closest waterwheel straw.

Place the entire apparatus inside the sink. Direct the flow of the faucet down the mouth of the large plastic bottle. Slightly turn the faucet on.


Watch the water wheel work as the falling water hits the blades.

1) What happens to the bucket when it is empty? ...filled with water?

2) Try putting a small weight in the empty bucket. Does the bucket still rise?

3) What happens if you increase the force of the water from the faucet in a sink? Does the wheel do more work? [Niagara Falls versus a small creek]

4) What happens if you increase the distance that the water falls on the wheel? [Hint: The further the water has to fall, the more stored energy it has.] Discuss with your group and then write a few sentences describing the relationship between force and distance with wheels
See Also:

Make Your Own Water Rocket 

• Research based Biology Science Fair Projects
• Research based Chemistry Science Fair Projects
• Research based Earth,Energy,Environmental, Science Fair Projects
• How to make best Science Fair Project Demo video
• Make Your Own Water Rocket