Thermodynamics Introduction Introduction

Jump on in: a hot spring is just the place to talk about thermodynamics.

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Thermodynamics is one hot topic—its history includes war, the industrial revolution, fortune telling, and for good measure, Galileo makes an appearance. How could we not be excited?

Using the laws of thermodynamics, we can tell the future. Really. We can say whether a chemical reaction will happen or not. Pretty cool, we think. Or hot, as the case may be. And it all got started because a guy called Nicolas Leonard Sadi Carnot thought that more efficient heat engines could help the French win the Napoleonic Wars. Spoiler Alert: Napoleon lost.

Without what we know from thermodynamics, there'd be no space travel or refrigerators, and your sister's pony could theoretically keep up with the vehicles in a NASCAR race. In practice, though, we know that last part isn't true. Thermodynamics tells us why.

Thermodynamics explains how the random movements of the zillions of tiny atoms that make up everything under the sun (and beyond) relate to heat, temperature, volume, pressure, and work. Yes, work can be calculated. We talk about atoms in our biology and chemistry classes, but thermodynamics lets us determine things about the movement of these invisible specs of material by taking macroscopic measurements of temperature, volume, and pressure.

For example, if we inflate a Helium balloon, the ideal gas law will tell us how quickly the Helium atoms move around from measurements of the volume and pressure of the balloon. From there we can also calculate how much kinetic energy each little Helium atom carries.

We'll also learn why solids expand and contract when they move from a cold place to a hot place, and then back to a cold place again. Sound boring? We think not—if we didn't understand thermal expansion, our bridges would collapse as the seasons change. We'll just say a big "no thanks" to that.

So, we'll kick this discussion off with a shout out to the three laws of thermodynamics. These bad boys relate the internal energy of gases, or the kinetic energy of the molecules in a gas, to the heat energy and mechanical energy (i.e., work) that is done by the system that contains the gas.

If that sounds complicated, don't worry—we'll make sure things never get too hot to handle.