Rocket steps outside in a T-shirt and shivers. "The sun is out!" he says. "Why is it so chilly?"
Raven zips her jacket. "What do you notice? Sunny does not always mean warm."
Nova hovers above the porch. "Feelings can trick us," she says. "Tools give us numbers."
Rocket grins. "Then let's measure it!"
Weather is what the air outside is like at one place and time.
Scientists measure weather with tools, so they get numbers instead of guesses.
| Tool | What it measures |
|---|---|
| Thermometer | Air temperature, in degrees Fahrenheit or Celsius |
| Rain gauge | How much rain falls |
| Wind vane | Which direction the wind comes from |
| Anemometer | How fast the wind blows |
Rocket felt chilly in the sun. Raven felt fine in her jacket.
Feelings are different for different people. A thermometer gives everyone the same number.
Numbers can be written down and compared from day to day.
That is why scientists use tools to measure weather.
| Statement | True or false? |
|---|---|
| A thermometer can measure in degrees Fahrenheit or Celsius. | ? |
| A rain gauge measures how fast the wind blows. | ? |
| Weather tools give numbers instead of guesses. | ? |
| Sunny always means warm. | ? |
You know your weather tools! Tomorrow we read real weather data from a real city.