Cut the neck off a balloon, stretch the balloon over the top of a jar or small cup and secure it with a rubber band. Cut a straw in half and cut at an angle to make a point. Tape the straw to the balloon so the end is in the center and the pointed end extends over the edge of the jar or cup. Place tape over the full length of the straw that's on the balloon so that it's secure. Make a gauge by folding an index card in half (or taping two together in a V shape) so that it stands next to the straw. The card should be about twice as tall as the jar. Mark on the index card gauge the location where the straw points each day. 

Rain Gauge

Materials

• Plastic bottle, 1- or 2-liter (with straight, not curved, sides)
• Gravel
• Ruler
• Tape

Directions

Cut off the top fourth of your plastic bottle. Add about two inches of gravel to the base of the bottle. Tape a paper ruler on the outside of the bottle, with the "0" mark at the top of the gravel. Add water until it reaches the top of the gravel. Make a funnel by inverting the top of the bottle that you cut off, placing it inside the base and covering the cut edges with tape. When it rains, measure the rainfall amount on the ruler.

Anemometer

Materials

• String
• Ping pong ball
• Scissors
• Tape 
• Protractor (you can use this protractor template)

Directions

Tape one end of a piece of string to a ping pong ball and the other to the center of the straight edge of a protractor. Hold the anemometer with the straight edge on top, parallel to the floor. Note the angle of the string when the wind blows, then use it to calculate the wind speed. Check the chart on our protractor template for this calculation.

General materials

• Thermometer
• Tray or box
• Weather log

What's happening?

Weather describes the temperature, humidity, atmospheric pressure, wind, rainfall and other meteorological characteristics of the atmosphere in a specific place at a specific moment in time. Instruments help measure the weather. A barometer measures air pressure; low or falling pressure (when the straw points downward) means a storm is approaching, while high or rising pressure (when the straw points up) means sunny weather. A rain gauge measures how much rain falls at a time. An anemometer measures the speed of the wind.

Extensions

Collect data for an extended period of time. Note the daily temperature and observations of what you see outside (sun, clouds, etc.). Guess what tomorrow's weather will be by using the patterns you have observed from your weather station. You can even make a video forecast like a TV meteorologist, then check the next day to see if you were correct. 

Recommended reading

Down Comes the Rain by Franklyn M. Branley

Magic School Bus Presents: Wild Weather by Sean Callery