WHAT ARE WE MEASURING?
We are measuring Wind Wind speed Wind direction
We are measuring Precipitation Rain Snow
We are measuring Air Pressure High or Low?
We are measuring Temperature Hot or Cold
Why do we measure these things?
We want to be able to predict and describe the weather It helps us plan what to wear It can help us avoid dangerous weather It can tell how to care for plants and crops
How does a thermometer work?
A thermometer is a glass tube filled with liquid, usually mercury or alcohol
The liquid expands when it is hot and shrinks when it is cool
The tube has numbers on it to tell you what the temperature is by measuring how much of the tube the liquid takes up
What is a cool way to measure wind speed at
home
The instrument used to measure wind speed is an anemometer
You can make your own anemometer by gluing a ping pong ball to a string and tying it to a protractor
By measuring the angle of the string on the protractor you can estimate the wind speed!
How do you measure precipitation
Rainfall is measured by collecting rain in a rain gauge
Rain gauges are usually about 50 cm tall and are placed on the ground just high enough to avoid splashes
Rain water is caught in a funnel on top, runs down into a cylinder below where it can be measured
How do we measure air pressure
With a Barometer
It tells you if the air pressure is rising or falling
A rising barometer pressure means sunny and dry weather
A falling barometer pressure means stormy and wet weather