Name: ___________Naomi Scharf___________________________
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. __________________________________________________________________________
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. ________________
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. _______
B. How does the change in temperature affect the volume of the container? __As the temperature decreases the container gets smaller and as the temperature increases the size of the container increases. _______
Get the Gizmo ready:
On the BOYLE’S LAW tab, set the temperature to 300 K and press OK.
Question: How does pressure affect the volume of a gas?
1. Form hypothesis: In this experiment, you will pile weights on the lid of the container of gas. What do you think will happen as more weight is added to the lid?
_if the pressure is increased, then the volume will decrease. ________________________________________________________________________
2. Notice: Look at the DESCRIPTION pane. What is the mass of the lid? ___10 Kg ______________
How much pressure does the lid exert on the gas? ____98.1 ____________________________
3. Collect data: Using the Select mass slider to place weights on the lid, record the pressure and volume of the gas for each of the following settings.
Added mass on the lid
Total mass (lid + added mass)
*This model does not include atmospheric pressure, which is 101,325 N/m2.
4. Analyze: As the pressure increases, what happens to the volume of the gas? ___it decreases________
This relationship is called Boyle’s law.
5. Calculate: Compare the pressure and volume values in your data table.
A. How did doubling the pressure change the gas volume? _it was half of the volume ____________________
B. How did tripling the pressure change the gas volume? __it was 1/3 of the...
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