In this submitted lesson, students will track the weather and notice patterns in air pressure. Students will also see how understanding density differences can be used to measure temperature.
This covers standard 6.3.2:
Investigate the interactions between air masses that cause changes in weather conditions. Collect and analyze weather data to provide evidence for how air masses flow from regions of high pressure to low pressure causing a change in weather. Examples of data collection could include field observations, laboratory experiments, weather maps, or diagrams.
This lesson uses Galileo thermometer and a liquid globe barometer.
How does the thermometer work?
A Galileo thermometer uses the principle of buoyancy to indicate temperature changes by the movement of glass balls in a sealed glass tube. The thermometer contains a clear liquid and several glass balls of different weights and colors, each filled with a liquid. The balls float or sink based on their density relative to the liquid and the temperature. A rising ball indicates a temperature drop, while a falling ball indicates a temperature rise. The temperature can be read from the metal tag attached to the lowest floating ball in the top half of the thermometer. As the temperature increases, the liquid expands and becomes less dense, causing the balls to sink. When the temperature decreases, the liquid contracts and becomes denser, causing the balls to float. The thermometer is named after Galileo Galilei because he discovered that a liquid’s density changes in proportion to its temperature.
How does the globe barometer work?
A weather globe barometer uses a glass tube connected to a globe filled with water. The air trapped in the globe maintains a steady pressure, and the water level in the tube rises or falls based on the atmospheric pressure.
Directions:
Have students chart weather daily or weekly. (see attached chart) Sunrise and sunset information can be found in a weather app. Encourage students to compare the app to Galileo’s thermometer. Point out that the thermometer uses the density differences of liquids to show the temperature. After tracking for a few weeks or over the course of months, see if students can see the following differences.
1. As the length of day increases, temperature tends to go up and conversely as the length of day decreases, temperature tends to go down.
2. Notice how the Galileo thermometer is not as specific as a modern thermometer or the online information. Also the barometer does not use precise measurements.
3. Depending on when you choose to have students track, hopefully they can see that before storms, the pressure in the barometer changes usually the day before.
