Because the weather changes from time to time and place to place, scientists use instruments to measure the weather conditions. They often group the instruments at one location, called a weather station. The scientists use the information they collect from many stations to make weather forecasts.
To make a weather station at home, consider the making or buying some of the following equipment:
- • Outdoor thermometer to measure temperature
- • Anemometer to measure wind speed
- • Wind or weather vane to record wind direction*
- • Rain gauge to measure precipitation*
- • Barometer to measure pressure*
- • Hygrometer to measure amount of moisture in the air*
*The Franklin Institute has an excellent section describing how to build the weather vane, rain gauge, barometer and hygrometer.
You may make a thermometer to see how one works, but you will need a regular thermometer to be able to take reliable readings outdoors. Watch the video to see how to make a simple thermometer in this blog post about water and thermometers.
A Simple Weather Vane
Gather for each child:
- • A plastic drinking straw (body of vane) – straight, not the bendy kind
- • A pencil with a sturdy eraser (support the vane)
- • Index card, piece of file folder or heavy construction paper (for tail of vane)
- • Dressmakers pin
- • Scissors
- • Tape (optional)
- • Markers and/or crayons
- • Container about the size of a small flowerpot, or old flowerpot
- • Soil, pebbles or similar material to hold pencil upright in the container
- • Compass to find north, east, west and south, only one needed to share
Cut two slits across one end of the straw, about one inch long.
Make a decorative tail for the vane. Cut the index card or paper into a weather-related shape, such as a raindrop, a sun or a flat-bottomed cloud. Make it about two inches in length. Have the children color their decoration. Slip the midline of the tail into the slits in the straw. If it doesn’t fit tightly, add a bit of tape to keep it in place. If you plan to use it for an extended period outside, you might want to consider laminating the tail.
Fill the container at least part way with soil or pebbles. Place the pencil upright in the middle of the soil, with the eraser end up. Push into the soil until the pencil will stand up on it’s own, with the top eraser at least a few inches above the rim of the container. Add more soil as needed.
An adult will need to supervise this step closely. Insert the dressmaker’s pin through the straw about two inches from the tail, in such a way that the fan is oriented up and down. The wind will be blowing from the side, so the tail should be positioned to catch the wind. Because the tail adds weight, the pin needs to be nearer the tail, rather than in the center, to balance. Once the pin is in place and oriented correctly, then push the pin into the top of the eraser. Blow on the weather vane to see if it can spin freely. If not, make the necessary corrections and try again.
To finish, take the weather vane outside where the wind might blow. Use the compass to determine the directions. Mark the container with north, south, east and west. Once the pot/container is marked, leave it in place. If it gets moved, be sure to correct the position with the compass. Record the wind direction as it changes over time.
You can easily modify the weather vane into an anemometer, which is a device to measure wind speed rather than direction. Or make another using the directions above.
- •Weather vane and materials above
- • Large needle or sharp nail
- • Two pieces of cardboard about 1½ inches wide by about 18 inches long
- • 4 foil muffin tin liner cups, or bathroom-sized paper cups
- • Staples or tacks
- • Watch or timepiece with minute hand
Remove the pin/straw from the eraser, but leave the rest of the weather vane intact. Cross the two pieces of cardboard and mark the center. Cut a slit half way through the middle of each, turn one over and then slide the two pieces together. They should overlap and form an X-shape.
If you are using paper cups, cut the rims off to reduce the weight. Staple or tack the muffin cups or small paper cups to the ends of each strip of cardboard, so they are all facing the same direction, for example in a clockwise direction. These are the cups that will catch the wind and be pushed around. Chose one arm and color the cardboard with a marker. This will help you count how fast the anemometer is revolving.
An adult will need to help with this step. Take the needle or sharp nail and drive it through the center of the cardboard X in such a way that the cups will rotate around from side to side. Once the needle through, push the point into the pencil eraser as before. Blow on the muffin cups and see if they will spin. Adjust accordingly. You may have to replace the needle if it is too short, or trim up the cardboard arms. Add staples if it is out of balance. Make the hole in the center larger, if it is too tight.
Take the anemometer outside. Place on a table or other structure, so it isn’t on the ground. Count how many times the colored arm passes per minute as a measure of wind speed.
Take your equipment outside at least once a day. Record the results. Check with local forecasts to see if your results match theirs. Note: Often the official weather station is in a shed or box to prevent the equipment from being exposed to direct sunlight. How might that change their results from yours?