Weather affects everyone. We all want to know what the weather will be like over the next few days — will we need to wear sandals and shorts or a coat, boots and gloves? How does the weather forecaster on TV predict rain tomorrow when the sky is blue today? In these experiments, you will be making some observations that will help you gain a better understanding of weather.
Earth's atmosphere surrounds the planet; it is the mixture of gases we breathe as air. As weather patterns move around, air particles may “bunch up” over a particular area. More particles mean increased atmospheric pressure.
When pressure is high, it prevents clouds from forming, and the weather is likely to be fair. When air pressure is low, clouds form more easily and there is a greater chance of rain or snow.
In this experiment, you will use a balloon to make a barometer that will measure changes in atmospheric pressure.
Cloud in a bottle
We have seen that air pressure is one factor in cloud formation. What are some of the other factors that cause clouds and precipitation? In this experiment, you will create a cloud in a bottle.
Measuring relative humidity
You may have noticed that humidity (the amount of water vapor in the air) makes a difference in how comfortable you feel outside. When the humidity is high in the summer we say it is "muggy." When it is cool and humidity is high we may say that it feels "clammy."
Humidity can make a warm day feel warmer and a cool day feel cold. In this experiment, you will put together a device called a psychrometer, with which you can calculate the relative humidity in the air.