The purpose is to determine if wind speed is different at ground level compared to 30 or 40 feet above ground.
The rotation of the Earth and differences in atmospheric temperature give birth to an inexpensive and renewable source of energy … the wind.
Down through the centuries, wind has been a powerful source of energy that mankind has harnessed to do work. The wind fills the sails of ships and turns the blades of windmills, which once were used to grind grains and saw wood, and today are used for generating electricity.
Studying the behavior of the wind is one of the most important aspects of meteorology, and it leads to a better understanding of weather and weather forecasting.
Is the speed of the wind different at different heights above the ground? Have you ever been sitting on the ground and, while you only felt a slight breeze, you could see the tops of very tall trees swaying in what appeared to be a stronger wind? Are the blades of windmills built up high because it is usually windier up high than it is near the ground?
Hypothesize that the wind is often stronger at a higher distance from the ground.
- Nine feet of ribbon, 2 inches wide
- One-week period of time
- Several clip-type clothespins
- Use of a high flagpole
- Pencil and sketch pad
- Use of a camera (optional, but useful in making a science fair presentation)
- Possible adult supervision needed
The location of the flagpole, the height of each ribbon wind indicator, and the ribbon indicators themselves are constant. The wind speed is the variable.
Get permission to use a tall flagpole that is away from buildings and other structures. Sometimes, local businesses will have high flagpoles for promotion. Your school may also have a tall flagpole.
Cut three 3-foot lengths of ribbon, the kind used for decorative craft work. The ribbon should be about 2 inches wide.
Tie the three pieces of ribbon onto the rope that hoists up the flag. Space the ribbons so that when the rope is pulled up, one ribbon will be at the top, one at the middle, and one at the bottom of the pole.
Every day at the same time for seven days, observe the position of the ribbons. Use a sketch pad to record your observations. The ribbons will give a relative indication of wind speed. The straighter they stand out (parallel to the ground), the stronger the wind speed.
If there is a day when no wind is blowing and none of the ribbons are moving, do not record an observation. Instead, wait until another day when there is enough wind to move at least one of the ribbons.
If stormy conditions exist, do not record your observations. Being outdoors in bad weather is unsafe, especially during a thunderstorm.
If the wind is very strong during one of your observation days, and all three ribbons are standing out straight, try adding weight equally to all of them, so they will not all stand out straight. Weight can be added by clipping one or more alligator-type clothespins to each ribbon.
Write down the results of your experiment.
Come to a conclusion as to whether or not your hypothesis was correct.
- Compare your ribbon wind indicators at different times of the day: early morning, noon, and dusk.
- Can you determine any relationship between the strength or direction of the wind and a barometer reading and the type of clouds?