Properties of Gases

Introduction

Have you ever wondered why a hot air balloon inflates when you fill it with hot air?  Or, why your bicycle tires seem more inflated during the summer than winter?  In this webquest, you will be able to explore the fascinating properties of gases to solve these mysteries!  

Gases have various properties that we can observe both with our senses and with instruments.  Three such properties are pressure, temperature and volume.  It has long been known that these three properties are related to each other.  By understanding these relationships, it is possible to explain why gases behave a particular way under different conditions. 

This Webquest allows you to develop a better understanding of the properties of gases using a computer simulation.  In particular, you should learn how changes in volume, temperature and pressure interact in a closed system.   

Task

After reflecting on what you already know about gases from experience with your partner, you will experiment with the simulation to develop a better understanding of how a gas’s temperature, volume and pressure interact in a closed system.  With this knowledge you and your partner should be able to answer several questions about the properties of gases and be able to make predicitions about real life scenarios.  You should e-mail your answers to the teacher when you are finished.  

Process and Resources

Step One.      Download and save this document to your computer: http://www.mediafire.com/?sv1x5vn2nhxxkci.

Step Two.      Answer the first question on the document:

                    

What do you know about the properties of gases?  For example, what happens when you heat a gas in a closed space?  Or, what happens to the pressure of the gas when you decrease the volume? Write as much as you know.

Step Three.    Skim through the information in the following links to familiarize yourself with the Ideal Gas Law:

Visual description: http://www.youtube.com/watch?v=WScwPIPqZa0

Written description: http://cnx.org/content/m12598/latest/

Step Four.      Run the gas simulation: http://phet.colorado.edu/en/simulation/gas-properties.  Answer questions 2 to 5 on the document.

Step Five.      E-mail your document to your teachers: marsh344@umn.edu and ytdl@hotmail.com.

Step Six.        Post your real-life example as a comment on this blog.  We will be using these examples in class at a later time. 

Evaluation

The evaluation is based on completion of the worksheet that you turn into the teacher. The following rubric pertains to the questions asked on the worksheet.

Question 1	Student answered the question and provided examples.	Student answered the question, but did not provide examples.	Student did not answer the question.
Question 2	Student correctly answered at least 80% of the table.	Student answered 50 to <80% of the table correctly.	Less than 50% of the table was answered correctly.
Question 3	All three of the graphs display proper relationships between the variables.	Two of the three graphs display proper relationships between variables.	One or none of the graphs display proper relationships between variables.
Question 4	Three or more of the scenarios had an accurate answer describing the phenomena.	Two of the scenarios had an accurate answer describing the phenomena.	One or none of the scenarios had an accurate answer describing the phenomena.
Question 5	A relevant example was provided by the student, and an accurate description of what variables were at play was given.	A relevant example was provided by the student, but no description was given.	Either an inaccurate example or no example at all was provided.

Conclusion

By completing this Webquest, you should have a better understanding of how a gas’s temperature, pressure and volume are related.  Furthermore, you should be able to use this understanding to explain what is happening in several real-life situations.