Comparing Heat & Temperature

Instructor: David Wood

David has taught Honors Physics, AP Physics, IB Physics and general science courses. He has a Masters in Education, and a Bachelors in Physics.

Heat and temperature aren't the same thing, contrary to everyday usage. Learn about the differences between the two concepts in science. Test your understanding with a quiz.

Definitions of Heat and Temperature

Heat and temperature are two similar concepts; it's understandable to mix them up. This is partly because scientific and everyday meanings of words aren't always the same. A person might say, 'The heat here is unbearable!' And nobody would think anything of it. But if a scientist says it, that would be a different matter. A physicist might say, 'The temperature here is unbearable!' To understand this, we need to look at what those two words really mean.

Temperature is a measure of the average movement (or kinetic) energy of the molecules in the substance. A higher temperature means the molecules are moving faster. In day-to-day life, we usually use Fahrenheit or Celsius as the units of measurement, but the scientific unit is kelvin.

Comparison of the Temperature Scales
Comparison of the Temperature Scales

Heat is the total energy that those moving molecules have. It includes both the movement (kinetic) energy of the molecules, and the potential energy of the molecules.

The majority of heat energy on Earth originally comes from the sun, though some is a result of radioactivity in the Earth.

The heat from the sun is the source of most of the heat energy on Earth
The heat from the Sun is the source of most of the heat energy on Earth

So if a higher temperature substance has more heat energy, and both are about molecular movement, are they really that different? Let's go through a few examples of why the difference is important.

Transfers and Heat Content

The heat content of an object or substance is very different than the temperature. For example, let's say you have two glasses of water: a small one for your younger brother, and a large one for you. Both those glasses of water came from the same pitcher in the refrigerator, so they're at the same temperature.

But since the glasses of water are so much different in size, they have totally different heat content. The larger glass of water contains more heat content because although the average movement energy of the molecules is the same, the large glass of water has so many more of them. Since heat content is the total kinetic and potential energy, the large glass has more heat content.

Temperature and Molecular Motion
Temperature and Molecular Motion

However, when scientists talk about heat, they're usually talking about heat transfers, not heat content. Temperature cannot be transferred from one place to another - temperature is not energy, it's just a measure of the hotness (movement of molecules) of a thing, but heat can transfer because it's a type of energy. When a hotter temperature object is in contact with a colder one, the molecules bump into each other randomly, and heat will transfer from the hotter object to the colder object.

Types of Heat Transfer

While heat and temperature are not the same, heat transfer does lead to changes in temperature. There are three ways that heat can transfer: conduction, convection and radiation.

To unlock this lesson you must be a Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use

Become a member and start learning now.
Become a Member  Back
What teachers are saying about
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create an account