Mini-Lab: Investigating Gas Laws

Tania Lauby, South St. Paul High School, South St. Paul, MN

The concept of mini-labs originated from Dr. Dan Branan and Dr. Matt Morgan. See mini-labs.org for more details!

Summary

In this chemistry lab activity, students investigate gas laws based on in-class mini-labs. Students are given no background and are required to complete two activities on their own to determine the relationship between gases and certain variables (temperature, volume and pressure). Students are then required to watch a demonstration and determine what variables are involved. Their final piece is to research and determine what laws they are dealing with (in this case, Charles or Boyle's). The outline is attached below.

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Learning Goals

Students will investigate two of the gas laws: Charles and Boyle's through a lab activity. They should be utilizing observation, inquiry and critical thinking skills.

Concepts:
1. Charles Law relates to temperature and volume. It states that as the temperature of a gas changes, so does its volume. It demonstrates a direct relationship between the two variables (ex: as one goes up, the other goes up).
2. Boyle's Law relates to volume and pressure. It states that as the volume of a gas changes, so does its pressure. It demonstrates an inverse relationship (ex: as one goes up, the other goes down and vice-versa).

Key Terms:
Temperature
Pressure
Volume
Direct
Inverse
Charles Law
Boyle's Law

Context for Use

This mini-lab is best used in a physical science class, where students are investigating gas laws. The educational level should be 9th grade or close to it and class size isn't much of a factor (dependent on supplies perhaps). Materials include Erlenmeyer flasks, balloons, hot plates, tongs, syringes, mini-marshmallows, pop cans, and a cold water bath. No previous knowledge is required. This activity could be furthered by incorporating activities about Ideal Gas Laws, Dalton's Law, Avogadro's Law, etc.

Description and Teaching Materials

In this lab, students will investigate Charles and Boyle's Law with no previous knowledge of either. Materials used are described in the section above. See the outline attached for further description. This mini-lab was adapted from demonstrations I had done in class. My goal was to put the responsibility of knowledge back on the students shoulders and to hold them more accountable for their understanding of gas laws. The concept of mini-labs was originated by Dr. Dan Branan and Dr. Matt Morgan. With Dr. Matt Morgan's consent, I have created a mini-lab of my own. See mini-labs.org for more details! Mini-Lab: Investigating Gas Laws (Microsoft Word 2007 (.docx) 16kB Aug3 09)

Teaching Notes and Tips

I have not personally done this activity as a lab in class yet. In the past, I have simply done a variety of demonstrations to help students understand Charles and Boyle's Law. In the future, I'd like to extend this lab to include other gas laws. Please feel free to email me with suggestions on how to improve this mini-lab. I appreciate all comments and suggestions. I feel that is the best way to improve myself as an instructor. Thank you.
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Community Contributions

Aug 26, 2024
I used this activity as a minilab for my G11 Chemistry class as an inquiry/exploration activity before we got into the gas laws. I had to slightly modify it due to complications (had to teach away from my classroom and used video demos for anything involving a hotplate).

I would be more specific with the instructions on how to prepare the syringe in STATION 2. The way it is written it is not clear for the students to seal the syringe after the marshmallow is in.

Assessment

I will require that the students complete the lab and turn it in at the end of the hour. Each will be required to turn one in, and all must complete the last question individually. From there, I may decide to have groups evaluate each others performance and participation.

Standards

9C.2.1.4.2

Explain changes in temperature, pressure, volume and number of particles of a gas in terms of the random motion of molecules in an ideal gas.

References and Resources