In this lesson our instructor talks about temperature and heat. First, he discusses absolute zero, kelvin, and heating water. Then he talks about specific heat and heat transfer. Four complete example problems round up this lesson.
All atoms and molecules have some vibrational motion in them, even solid objects. We call the average of this motion in a substance temperature (T).
Since temperature is based on motion, the lower limit of this is when the objects stop moving: this is called absolute zero.
We measure temperature in kelvin (K). Absolute zero is 0K. One kelvin is the same "size" as a Celsius degree, but they have very different starting points. We can convert between them with
TC = TK − 273.15.
Heat (Q) is the transfer of thermal energy. Heat is positive when the environment puts thermal energy into the system, and negative when the environment takes energy out.
One calorie (cal) is the amount of heat required to raise one gram of room temperature water by one kelvin/one degree Celsius.
Since thermal energy is a form of energy, we can covert calories to joules:
1 cal = 4.1868 J.
Different materials take different amounts of heat to have the same change in temperature. The specific heat (c) of an object tells us the proportion of heat to temperature change. Different substances have different specific heats.
The more mass an object has, the more thermal energy it takes to increase its temperature. In general, the amount of heat required for a change in temperature is
Q = cm(∆T).
Intro to Temperature & Heat
Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.
This book includes a set of features such as Analyzing-Multiple-Concept Problems, Check Your Understanding, Concepts & Calculations, and Concepts at a Glance. This helps the reader to first identify the physics concepts, then associate the appropriate mathematical equations, and finally to work out an algebraic solution.