Heat and temperature (article) | Khan Academy
We often refer to infrared radiation as being primarily heat (or thermal) radiation. But what exactly is heat, and how does it differ from temperature? Simply put. Heat is the energy that flows between two objects that are at different temperature . Temperature is a measure of how hot or cold a substance is relative to. In this lesson, we're going to learn about the relationship between heat and temperature. We'll explore how they affect each other by working.
Temperature is also an intensive property, which means that the temperature doesn't change no matter how much of a substance you have as long as it is all at the same temperature! On an atomic level, the molecules in each object are constantly in motion and colliding with each other.
What is the relationship between heat and temperature?
Every time molecules collide, kinetic energy can be transferred. When the two systems are in contact, heat will be transferred through molecular collisions from the hotter system to the cooler system.
The thermal energy will flow in that direction until the two objects are at the same temperature. When the two systems in contact are at the same temperature, we say they are in thermal equilibrium. Zeroth law of thermodynamics: Defining thermal equilibrium The zeroth law of thermodynamics defines thermal equilibrium within an isolated system.
The zeroth law says when two objects at thermal equilibrium are in contact, there is no net heat transfer between the objects; therefore, they are the same temperature. Another way to state the zeroth law is to say that if two objects are both separately in thermal equilibrium with a third object, then they are in thermal equilibrium with each other. The zeroth law allows us to measure the temperature of objects.
Any time we use a thermometer, we are using the zeroth law of thermodynamics. Let's say we are measuring the temperature of a water bath. Its measurement can be done in energy units, i.
How does Temperature Differ from Heat?
The transfer of heat can take place in three ways, which are — Conduction: Heat transfer between molecules which are in direct contact with each other, without the movement of particles. The transfer of heat that takes place due to the movement of particles from one place to another is convection.
When the heat is transferred through a medium or vacuum, wherein space in between, is not heated up. Definition of Temperature Temperature is defined as the average kinetic energy of all molecules together, i.
What is the relationship between temperature, heat, and kinetic energy?
As an average measurement, the temperature of a substance does not rely on its size number of particles and type. It identifies how hot or cold an object is, in degrees.
It also measures, the speed of atoms and molecules of the substance. It can be measured in various scales, which are — Kelvin, Celsius and Fahrenheit. The thermometer is used to gauge the temperature of the object. Key Differences Between Heat and Temperature The differences between heat and temperature can be drawn clearly on the following grounds: Heat is nothing but the amount of energy in a body.