What You Will Do:
- Explore how the motion of air molecules changes with temperature and how these motions form a Maxwell-Boltzmann distribution, a curve showing the range of molecular speeds in a gas.
- Use your Observe Temperature Sensor to collect real-time temperature data and watch how the predicted particle speeds shift as the air warms or cools.
- Analyze a histogram of simulated molecular speeds in Desmos and compare it with the theoretical Maxwell-Boltzmann probability curve and the calculated root mean square velocity (Vrms).
- Watch the Khan Academy video "Maxwell-Boltzmann Distribution" to learn how molecular speeds are distributed in a gas and how temperature affects the shape of the curve.
- The root-mean-square velocity (Vrms) is a type of average speed that represents the typical motion of gas molecules. It is calculated by squaring each molecular speed, finding the mean of those squares, and then taking the square root.
- The Vrms value comes from the Maxwell–Boltzmann distribution, which shows how molecular speeds are spread out at a given temperature. As temperature increases, the entire distribution shifts toward higher speeds, and the Vrms also increases.
- Click this link Molecular Speeds Worksheet to open the worksheet in a new browser tab. Click ‘Make a copy’ to save your version to your Google Drive. Use the simulation as you answer these questions.
- Click to watch this Khan Academy video to learn more about these concepts.
- Click the Show Directions button in the upper-right corner to learn how to collect temperature data for this simulation activity.
Directions:
- Use a USB-C cable to connect the Observe Temperature Sensor to your computer’s USB port.
- Click the Connect button at the top-left corner of this page.
- Select the USB serial port (COM X) and click Connect. The “X” varies by computer.
- Confirm that the status in the top-right corner says “Connected.”
- Set the sensor on the table and do not touch the metal tip. This will measure your room’s temperature.
- Click Start Collection to begin. Click Stop Collection to finish. Particles remain still until you start.
- Hold the sensor in ice water, then move it to hot water, and observe the simulation changes.
Vrms: —