Boyle’s Law and Charles’ Law (Student Exploration)

Vocabulary: absolute zero, Boyle’s law, Charles’ law, Gay-Lussac’s law, Kelvin scale, pressure Prior Knowledge Question (Do this BEFORE using the Gizmo.) A small helium tank measures about two feet (60 cm) high. Yet it can fill over 50 balloons! How can such a small tank contain enough helium to fill so many balloons? The tank can hold enough helium because the gas in the tank is under tremendous pressure. Gas will contract under high pressure, and expand under low pressure. When the helium goes into the balloons, it occupies much more space because there is less pressure in the balloons than in the tank Gizmo Warm-up The Boyle’s Law and Charles’ Law Gizmo™ shows a container of gas. In the container, the small purple spheres represent molecules. 1. Observe the particles. Are they all moving at the same speed? No, the particles are moving at different speeds 2. How do the particles interact with the walls and lid of the container? The particles bounce off the walls and lid of the container These interactions contribute to the pressure on the walls of the container. Pressure is defined as force per unit area. The SI units of pressure are newtons per square meter (N/m2 ), or pascals (Pa). 3. Slowly drag the temperature (T) slider back and forth. (Note: In this Gizmo, the Kelvin scale is used to measure temperature. On the Kelvin scale, 0 degrees is absolute zero, the coldest possible temperature. Absolute zero is equal to -273.15 °C or -459.67 °F) A. How does the change in temperature affect the speed of the molecules? Moleculesmove faster B. How does the change in temperature affect the volume of the container? Volume increases