If you drink a glass of ice water on a hot day, what temperature is the ice? The answer comes down to the basic science of phase changes.
Transitioning from one phase of matter to another—like from solid ice to liquid water—requires energy. In fact, what we call temperature is really a reflection of kinetic energy, or the speed at which atoms in matter are buzzing about. Add energy into a system and you make the atoms buzz a bit more causing the temperature to increase.
So, imagine that you have a cup of ice and water. The ice might start a few degrees below its melting point, which is 32 degrees Fahrenheit. When we add energy into the system, by exposing the ice and water to hot temperatures, the temperature of the ice will increase, but only until it gets to its melting point. Then, the energy added to the system will be used to shift the ice from a solid to a liquid. This means that as the ice melts, its temperature remains consistently at 32 degrees no matter how much energy is added, though the more energy added, the quicker the ice will melt.
Until the ice has melted entirely, the energy added to the system is only spent changing the ice from solid to liquid; once the ice has melted, though the energy added to the system can begin increasing the water’s temperature. So, next time you’re drinking a nice, cold glass of ice water, think about the remarkable science letting you stay cool and refreshed!
