What’s in the wind?
Many objects move through the air as the wind blows, even though we might not see them. For example, dust from the Sahara desert has been carried as far west as Puerto Rico by winds! Strong winds from tornadoes have been known to pick up all sorts of objects — cars, wood, trees, even frogs! — and drop them off in new locations. Some plants depend on wind to disperse their seeds.
What’s in the wind near you? Find out with this experiment (courtesy of Weather Wiz Kids®).
What you need:
- A few plastic lids (white or light in color, if possible)
- A few plastic lids
- Petroleum jelly
- Magnifying glass
- Paper punch
- Yarn
- Windy day
What to do:
- Punch a hole at one end of each lid.
- Thread each hole with a length of yarn and knot the ends of the yarn together to form a loop for hanging.
- Spread petroleum jelly over one side of each lid.
- Take the lids outdoors on a windy day and hang them in various areas.
- Leave them outside for about an hour or two to collect what may be blowing in the wind.
- Retrieve the lids and see what they have collected. Some of the items that may have been collected include insects, dirt, seeds and leaves. Use the magnifying glass for further observation.
Image: Seeds from many plants can be found in the wind. Seed images from the Family Guide for Fruits and Seeds, courtesy of the U.S. Department of Agriculture’s Agricultural Research Service.
5 three ounce paper Dixie Cups
2 soda straws
pin
paper punch
scissors
stapler
sharp pencil with an eraser
PROCESS:
Take four of the Dixie Cups and use the paper punch to punch one hole in each, about a half inch below the rim.
Take the fifth cup and punch four equally spaced holes about a quarter inch below the rim. Then punch a hole in the center of the bottom of the cup.
Take one of the four cups and push a soda straw through the hole. Fold the end of the straw and staple it to the side of the cup across from the hole. Repeat this procedure for another one-hole cup and the second straw.
Slide one cup and straw assembly through two opposite holes in the cup with four holes. Push another one-hole cup onto the end of the straw just pushed through the four-hole cup.
Bend the straw and staple it to the one-hole cup, making certain that the cup faces the opposite direction from the first cup. Repeat this procedure using the other cup and straw assembly and the remaining one-hole cup.
Align the four cups so that their open ends face in the same direction either clockwise or counter-clockwise around the center cup.
Push the straight pin through the two straws where they intersect.
Push the eraser end of the pencil through the bottom hole in the center cup. Push the pin into the end of the pencil eraser as far as it will go.
Now your anemometer is ready for use!
EXPLANATION:
An anemometer is useful because it rotates with the wind. To calculate the velocity at which your anemometer spins, determine the number of revolutions per minute (RPM). Next, calculate the circumference (in feet) of the circle made by the rotating paper cups. Multiply your RPM value by the circumference of the circle and you will have an approximation of the velocity of at which your anemometer spins (in feet per minute). Your anemometer doesn’t need to be pointed in the wind for use.
Note: Some forces are being ignored including drag and friction for this elementary illustration, so the velocity at which your anemometer spins is not the same as wind speed.