Math by Grades

Math by Topics

$Math Word Problems$

$Probability$

$Set Theory$

Math Worksheets $Math Worksheets$

Math for Specific Tests $SAT Math$
$ACT Math$
$GMAT Math$
$GRE Math$
$High School, Regents$

Math Fun and Games $Math Trivia$
$Math Games$

Exam Preparation

Math in Video Lessons $Basic Algebra$

$Engineering Math$
$Singapore Math$
Science

Others

$What's New$

Heat and Thermodynamics

A series of free High School Physics Video Lessons from Brightstorm online Physics series.

2nd Law of Thermodynamics
The 2nd Law of Thermodynamics can be rephrased in several ways. Fundamentally, it says that heat always flows from hot objects to cold objects (unless work is exerted to make it flow the other direction). It can also be expressed using the concept of entropy as saying that the system's entropy will always naturally increase if no work is exerted to decrease it. These rephrasings mean fundementally the same thing because heat deals with kinetic energy and increasing a system's kinetic energy will increase the system's entropy.

Entropy
Entropy measures the amount of disorder in a system. Nature tends towards disorder, so as time elapses, entropy naturally increases. Energy is required in order to decrease entropy.

Internal Energy
An object's internal energy is the kinetic energy from the random motion of the particles within it and the potential energy from movement of electrons in its atoms. Generally internal energy is represented with the letter U.

Measurement of Heat
Measurement of heat is done in calories. One calorie is the amount of energy required to raise one gram of water one degree Celsius. To measure heat, you divide the change in temperature of a sample of water by the mass of the water.

Thermal Expansion
Most matter expands when heated and contracts when cooled, a principle called thermal expansion. The average kinetic energy of the particles increases when matter is heated and this increase in motion increases the average distance between its atoms. It is important to note that water does not follow the rule of thermal expansion. Water expands when it freezes because the crystalline structure of ice takes up more space than liquid water.

Custom Search

We welcome your feedback, comments and questions about this site - please submit your feedback via our Feedback page.

Custom Search

Amazon.com Widgets