Student Exploration: Boyle’s Law and Charles’ Law
Vocabulary: absolute zero, Boyle’s law, Charles’ 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 is compressing the helium into a denser state but when it is put in the balloons it expands and takes up more space. __________________________________________________________________________
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Gizmo Warm-up
On the Boyle’s Law and Charles’ Law Gizmo™, check that the BOYLE’S LAW tab is selected. The Gizmo shows a container of gas; the little purple spheres represent molecules.
1. Observe the particles. Are they all moving at the same speed? _____No_______________________________
2. How do the particles interact with the walls and lid of the container? _They run into them and bounce off and go in another direction. ________________
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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? __If the temperature is colder the molecules move slower and if the temperature is hotter the molecules move faster.