###### Winter’s back in town…. somma1977. 2006. Flickr. 7 November 2008 <http://www.flickr.com>

Opening

If you live anywhere north of Florida, then the answer is yes, it’s cold outside. As a southern native living just outside of Chicago, yes cold hit today. Gray skies, cool crisp wind and threat of snow this weekend, all part of the Midwest experience, but what is cold? A better or more specific question, what is temperature? Think you know. Here’s what the masses say.

“Specifically, temperature is a property of matter. Temperature is one of the principal parameters of thermodynamics. On the microscopic scale, temperature is defined as the average energy of microscopic motions of a single particle in the system per degree of freedom.”

###### “Temperature.” Wikipedia, The Free Encyclopedia. 7 November 2008, 12:34 UTC. Wikimedia Foundation, Inc. 7 Nov. 2008. <http://en.wikipedia.org/wiki/Temperature>.

Meanwhile back at in the halls of science…

In this month’s issue of Scientific American the article “The Long Arm of the Second Law” by J. Miguel Rubi details the chaos of temperature. Even the second law of thermodynamics falls under attack. It appears temperature holds true only for systems in equilibrium, that glass of water that’s been sitting on your desk all day for example. Put the glass over a Bunsen burner at full blast and you’ve got what Rubi describes as a “severe disequilibrium.” (Don’t try this, you’ll glass may also shatter) Drop by your local book store, pick this issue up and read the 5 page article. In fact, you may want to buy or at least check this issue out from your library, you’ll thank me later.

So what’s this got to do with that science class you’ll be teaching tomorrow. Change. Heraclitus said, “Change is the only constant” back in the 4th century BC and it holds true to this day. In teaching and learning science, it’s easy to become bogged down by facts, figures and laws. We often forget that science is all about questioning the facts and refining those theories and laws. This article not only introduces your students to a current piece of fascinating research, but also shows them, even in the age of wikipedia and google, there’s always more to explore.
Current Research to Classroom Antics

If you’re studying properties of matter, then temperature is a concept your students should be familiar with. Most will say they know what temperature is. They’ve experienced hot, cold and everything in-between, but scientifically speaking, as the above article indicates, temperature is very complex. There are many, many demos/labs out there that show temperature, but can you remember one off the top of your head. I’ve got a couple to highlight here.

###### Paintball-birger. M. Johansson. 2007. Flickr. 7 November 2008 <http://www.flickr.com>

80 m/s = The Painful Velocity of a Paintball

Temperature is something we can feel. What we’re feeling is the high, or low, velocities of air molecules impacting our skin. Specialized nerve cells send signals up our spinal cords, to our brains, which interprets hot, cold and variations in-between. A paintball fired at around 80 m/s is another sensation our brain can register and interpret, to some unbelievable pain, to others a great time with friends. I may be in that first group, but paintballs can be used for science.

You need paintballs (paint filled sphere), a paintball gun (compressed air paint sphere accelerator) and a volunteer (may need to be you). This probably needs to be done outside, away from all living things. Start by having the students LIGHTLY toss the paint balls at you, or dump the paintballs over your head. Shouldn’t hurt. Why? The paintballs aren’t moving very fast, low velocity. Next, load up the paintball gun and have a trusted assistant (another teacher, that you’re friends with) fire off a lot of rounds. High velocity and unfortunately a little painful, I suggest padding. Your students just might get the idea. Are there easier ways, yes, but few as endearing.

###### Visor Shot. Stephen Witherden. 2008. Flickr. 7 November 2008 <http://www.flickr.com>

Virtually Show Molecules

Using an exploration in Discovery Education Science, you can show temperature and heat at the molecular level. So, if getting shot by paintballs isn’t your cup of tea. Try using the below to illustrate the point.