[1]
Purpose
To illustrate for students how a gas can be compressed (but not all the way) because of empty space between the particles.
Description
Show the states of matter simulation from the Molecular Workbench http://mw.concord.org/modeler/ [2]. After selecting Gas, click Run to start the simulation. Click Start Compression to move the plunger down. See the Implementation Tips below for more information on using the simulation.
Questions to Ask Students
- What do you think each of the dots represents?
- What are all of the dots doing? Describe how they are moving.
- What is between the dots?
- Can the plunger go all the way to the bottom of the container?
- How is this simulation similar to what you experienced with the syringe?
Student Thinking
- The demonstration confronts the following misconceptions:
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- Gases are continuous (Benson et al., 1993; Séré, 1986) [3]. In reality, gases, like all matter, are made of particles.
- Gases are nothing (Durmuş & Bayraktar, 2010; Stavy, 1988) [3]. In reality, gases, like all matter, have mass and volume.
Implementation Tips
- Tell students that the simulation will allow them to see a model of what they cannot see, even with the strongest microscope.
- Spend some time with the simulation before sharing it with the students. To run the simulation, you’ll first have to download the Molecular Workbench library by clicking Download MW. It should take only a minute. Once it has downloaded, click on the file to open it. Once you open it, click Browse Entire Library, and click on States of Matter under Chemistry. Then click on States of Matter to run the simulation.