Peer Review

Charles' Law

Material Detail page

Reviewed:: May 15, 2005 by Physics

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Ratings

Overall Rating:

Content Quality:

Effectiveness:

Ease of Use:

Overview:: This is a computer simulation that provides a qualitative visualization of the
origins of Charles' Law. A slider bar allows the user to vary the temperature
of a gas sample confined to a fixed volume. The speeds of the particles varies
as the temperature is changed. A meter shows the resulting gas pressure.

The text describes the relationship between the speed of the atoms and
temperature, and gives Charles' Law.
Type of Material:: Simulation
Recommended Uses:: In class demo or student assignment.
Technical Requirements:: Java applet
Identify Major Learning Goals:: To help students visualize the microscopic physics underlying Charles' Law.
Target Student Population:: High school and lower division undergraduate.
Prerequisite Knowledge or Skills:: Students should be familiar with the definition of pressure and the relationship
between temperature and average kinetic energy of a particle ensemble.

Content Quality

Rating:

Strengths:

The graphics clearly show the relationship between temperature and particle
speed, and pressure in a gas. A little bit of quantitative work can be
done, since the temperature and pressure are given, and the temperature
can be varied by the user.

Concerns:

It is a little difficult to tell, but it seems that the gas "atoms" all have the same speed rather than a Boltzmann distribution. This simulation should be presented as a qualitative model.

The scale on the pressure gauge has no units.

The terms momentum, speed and kinetic energy are used interchangeably by the
author (as being dependent on changes of T). This could be a bit confusing to
the beginning user. The meaning of the constant of proportionality (between P
and T) is not addressed.

Potential Effectiveness as a Teaching Tool

Rating:

Strengths:

This applet would make a nice in-class demo, and could be the basis of simple
student assignments.

The simulation is effective in that it illustrates, with moving atoms and a
moving barometer, the relationship between the kinetic energy of the atoms in a
gas and pressure.

Concerns:

The built-in exercise doesn't seem to test anything other than the student's
ability to read a pressure gauge.

The quantitative exercise has a wide range of acceptible answers.
The built-in exercise doesn't seem to test anything other than the student's
ability to read a pressure gauge.

The quantitative exercise has a wide range of acceptable answers.

Ease of Use for Both Students and Faculty

Rating:
Strengths:: Controls are simple and obvious. The applet has an attractive and easy to use
interface.
Concerns:: The scale on the pressure gauge should have more tics if useful numerical
readings are to be obtained.

Other Issues and Comments:: If the user enters no answer and clicks the "check the answer" button in the
quantitative exercise, the applet tells the user they are "correct".
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