# Physics

Topics: Thermodynamics, Heat, Energy Pages: 2 (556 words) Published: January 19, 2013
6. Applications
* Is it possible to add heat to a body without changing its temperature? Yes. It is possible to add energy to a body (in the form of heat) and not raise its temperature by causing a phase change. When you heat ice it takes energy to convert it from ice to water, but does not change the temperature of the body until it is all converted. The principle behind this is what we call latent heat. It refers to the energy (or heat) required to change the state of a substance without changing its temperature, the energy is used in breaking bonds in the structure of the material while changing state. * Explain why steam burns are more painful than boiling water burns. Because the steams contains extra heat energy than boiling water due to its specific latent heat of vaporization. Latent heat of vaporization is the energy given out or taken in when a substance changes state from liquid to gas or from gas to liquid with no temperature change in the system. The temperature of boiling water is 212 degrees, as is the temperature of steam. boiling water and steam cannot get any hotter than that unless you increase the pressure. So the temperature of each is the same at the same atmospheric pressure. The key difference is this: to get water at 212 degrees to turn to steam at 212 degrees you must add a lot more energy. Thus steam contains much more energy than water at the same temperature, which is why steam burns are so much worse. * Early in the morning when the sand in the beach is already hot, the water is still cold. But at night, the sand is cold while the water is still warm. Why? It is because the specific heat of water (4200 ) is higher than that of the sand (840 ). Specific heat is the amount of heat needed to raise the temperature of a unit mass of a substance by one degree. You're also only heating the surface of the sand to a depth of a few inches. With the sea, the motion of it ensures that the heat energy is dispersed more efficiently....