A backyard weather station is a hands-on way to measure the atmosphere where you live. By building simple instruments and collecting data every day, students can connect classroom science to real weather patterns. A two-week project can reveal changes in temperature, humidity, air pressure, rainfall, and wind.
These measurements also make it possible to compare your observations with a local forecast and judge its accuracy.
Key Facts
- Temperature measures how hot or cold the air is, usually in degrees Celsius or degrees Fahrenheit.
- Relative humidity is the percent of water vapor in the air compared with the maximum it can hold at that temperature.
- Rainfall depth can be measured with a rain gauge using V = A x h, where V is volume, A is collection area, and h is rain depth.
- Wind speed can be measured with an anemometer, and wind direction is named for where the wind comes from.
- Air pressure is measured with a barometer, and falling pressure often signals changing or stormy weather.
- Percent forecast accuracy = correct forecasts / total forecasts x 100%.
Vocabulary
- Thermometer
- An instrument that measures air temperature.
- Hygrometer
- An instrument that measures relative humidity in the air.
- Rain gauge
- A container with a scale that measures the depth of rainfall over a period of time.
- Anemometer
- An instrument that measures wind speed.
- Barometer
- An instrument that measures air pressure.
Common Mistakes to Avoid
- Placing the thermometer in direct sunlight gives readings that are too high because the instrument heats up more than the surrounding air.
- Reading the rain gauge on a slanted surface is wrong because the water depth will not be level and the scale reading will be inaccurate.
- Changing the observation time each day makes trends harder to compare because temperature, humidity, and wind often change throughout the day.
- Calling a forecast wrong without defining the target is misleading because forecast accuracy depends on what you compare, such as rain or no rain, high temperature, or wind speed.
Practice Questions
- 1 A rain gauge has a collection area of 50 cm2 and collects 75 cm3 of water during a storm. What rainfall depth h was measured, using V = A x h?
- 2 Over 14 days, a local forecast correctly predicted rain or no rain on 11 days. What was the percent forecast accuracy?
- 3 Your weather station shows falling air pressure, increasing humidity, and stronger winds compared with yesterday. Explain what kind of weather may be approaching and why.