*Adding glycerin to the bubble solution can make the bubbles last longer. Here's a link to a Flinn version with a "recipe" for bubble solution:
Another topic I would be teaching right now is Gas Laws. I am aware that some of you may have taught this at the beginning of the school year (that's how a lot of textbooks are set up).
It helps to relate the study of gases to Kinetic Molecular Theory.
Here is one overview of KM theory that has good animation of particle motion:
Boyle's Law is the relationship of pressure and volume of a sample of gas where the temperature and the number of moles of the gas are not changing,
Pressure x Volume = Pressure x Volume
As pressure increases, volume decreases -- or as pressure decreases, volume increases -- an inverse relationship.
Gas pressure is due to the collisions of the gas particles with the walls of the container. Going up in altitude (such as in an airplane), there is less atmosphere and the atmospheric pressure is decreased. I have had sealed bottles reduce in volume as and airplane has gone up in the atmosphere.
Here's another cute example using a bell jar to remove the surrounding atmospheric gas and reduce the pressure of the system:
Reducing pressure on the body (and blood), gases previously dissolved in the blood can escape, causing decompression illness (aka "the bends" ). If you want to read more about it, go to: http://www.diversalertnetwork.org/medical/articles/Decompression_Illness_What_Is_It_and_What_Is_The_Treatment
Here's an example of the pressure changes:
1 atm = 760 mmHg = 760 Torr = 29.92 inHg = 14.696 psi = 101.3 kPa
Also, volume units can be changed, even though milliliters is the most typical measurement students will encounter.
Including units in their work and being sure the units cancel is always important!
Here's an example of a solved problem:
Please let me know about your experiences, ask if you have any questions or if you have ideas for other topics for this blog.
And, check out my lab book "Chemistry on a Budget" at:
Have a good week!