An anemometer is a device that tells you how fast the wind is blowing. The device you can build is a model of a wind speed indicator. A real one will be able to accurately measure how fast the wind is blowing. Yours will give you only approximation of how fast it's blowing. It can't give you an exact wind speed.

The energy in the moving wind can be used to generate electricity. But you have to know how fast the wind is blowing before you can harness wind power.

What You'll Need

· Scissors
· 4 small paper cups (like drinking cups)
· A marking pen (any color)
· 2 strips of stiff, corrugated cardboard -- the same length
· Ruler
· Stapler
· Push pin
· Sharpened pencil with eraser on the end
· Modeling clay
· A watch that shows seconds

What to Do

1. Cut off the rolled edges of the paper cups to make them lighter.
2. Color the outside of one cup with the marking pen.
3. Cross the cardboard strips so they make a plus (+) sign. Staple them together.
4. Take the ruler and pencil and draw lines from the outside corners of where the cardboard strips come together to the opposite corners. Where the pencil lines cross will be the exact middle of the cross.
5. Staple the cups to the ends of the cardboard strips; make sure the cups all face the same direction.
6. Push the pin through the center of the cardboard (where the pencil lines cross) and attach the cardboard cross with the cups on it to the eraser point of the pencil. Blow on the cups to make sure the cardboard spins around freely on the pin.
7. Place the modeling clay on a surface outside, such as a a porch railing, wooden fence rail, a wall or a rock. Stick the sharpened end of the pencil into the clay so it stands up straight.

Your anemometer is now ready for use!

Measuring Wind Speed

This anamometer cannot not tell the wind speed in miles per hour, but it can give you an idea of how fast the wind is blowing.
Using your watch, count the number of times the colored cup spins around in one minute. You are measuring the wind speed in revolutions (turns) per minute. Weather forecasters' anemometers convert the revolutions per minute into miles per hour (or kilometers per hour). Keep a record of the wind speeds you're measuring for the next few days.
Measure the wind speed at different times of the day. Is it the same in the morning; the afternoon; the evening? Move your anemometer to another location. Is it windier in other places? Do trees or buildings block the wind?


Make A Thermometer

A thermometer is an instrument that measures the temperature. Temperature is measured in a scale called Fahrenheit (by most people in the United States) and in Celsius or Centigrade (used by scientists and by people in many other countries). The point where water freezes is 32 degrees Fahrenheit (F for short) and 0 degrees Celsius (C). The point where water boils is 212 degrees F and 100 degrees C. If you want to know how to convert from F to C or from C to F, see the end of this page.
Some scientific thermometers use the Kelvin scale, where 0 degrees Kelvin is called absolute zero -- a place where there is no movement of any parts of matter, where substances have no thermal energy. It's about minus 273.15 degrees C (below 0° C) or 459.67 degrees below 0° F. Scientists have never been able to measure anything at absolute zero, though they have gotten very close.
Thermometers help us know what the weather will be like. If it will be 90°F outside, we're not going to put on a winter coat. Or if it's below zero, we won't be wearing shorts. Here's a way to show how a simple thermometer works.
What You'll Need
· Tap water
· Rubbing alcohol (do not drink this)
· Clear, narrow-necked plastic bottle (11-ounce water bottles work well)
· Food coloring
· Clear plastic drinking straw
· Modeling clay
What to Do

8. Pour equal parts of tap water and rubbing alcohol into the bottle, filling about 1/8 to a 1/4 of the bottle.
9. Add a couple of drops of food coloring and mix.
10. Put the straw in the bottle, (DO NOT DRINK MIXTURE) but don't let the straw touch the bottom.
11. Use the modeling clay to seal the neck of the bottle, so the straw stays in place.
12. Now hold your hands on the bottle and watch what happens to the mixture in the bottle.
Congratulations!!! You just made a thermometer. Just like any thermometer, the mixture expanded when it was warmed. This made the liquid no longer fit in the bottom of the bottle. As the alcohol expanded the colored mixture moved up through the straw. If the bottle were to get very hot, the liquid would have come through the top of the straw.
You can watch your thermometer and see how the liquid changes throughout the day. What happens if your thermometer is in shadow or in sunlight? What happens when it gets colder? How does wind affect the thermometer?
Of course, in order to accurately read the temperature, you will need to buy a real thermometer that is carefully calibrated for temperature changes. This one is to see how a thermometer works -- just for fun.
After you're done with your thermometer, dispose of the liquid properly and rinse the bottle well. Cut it in half, or have a parent cut it in half, so the bottle can't be reused. Then recycle the plastic. The used bottle could have some left over alcohol in it, and you don't want anyone to reuse the bottle for drinking water. So, it's best to recycle the bottle.

Changing Temperature Scales
The Fahrenheit scale was named after Gabriel D. Fahrenheit who lived from 1686 to 1736. He devised a way of measuring temperature. The Celsius scale was named after Anders Celsius, its inventor, who lived from 1701-1744. The Celsius scale is also called Centigrade. The Centi in centigrade means 1/100 (one one-hundredth) for the 100 equal divisions on the scale and is used by scientists. It is the temperature scale used by most of the world. The difference between the temperature where water freezes and boils is an even number of degrees...100. In the Fahrenheit scale, the difference between freezing (32° F) and boiling (212° F) is 180.

You can change the temperature in Fahrenheit into Celsius using math.
Take your number; subtract 32° from it; and divide the remainder by 1.8.
Change 75 degrees Fahrenheit into Celsius.
75 - 32 = 43
43 / 1.8 = 23.88° C
So, 75° F is equal to 23.88° C

To change the temperature in Celsius to Fahrenheit: Multiply your number by 1.8 and add 32°.
Change 12 degrees Celsius into Fahrenheit.
12 x 1.8 = 21.6
21.6 + 32 = 53.6° F
So, 12° C is equal to 53.6° F