Lesson 1 Summary - Thermal Energy, Temperature, and Heat

All substances (solids, liquids, and gases) are made up of trillions of very tiny particles called atoms.  These atoms are constantly moving.

• Solids vibrate in place.

• Liquids slide around from side to side in a container.

• Gases fly around in all directions, moving quickly and freely.

The faster particles move, the more kinetic energy they have.

These atoms also have potential energy because they interact with and are attracted to each other.

• Solids are held very close together by attractive forces.

• Atoms in a liquid are a little bit farther apart than atoms in a solid.

• Atoms in a gas are much more spread apart than atoms in a solid or a liquid.

The greater the average distance between atoms, the greater the potential energy of the atoms.

Thermal energy is the sum of the kinetic and potential energy of the atoms in a substance.

Temperature is the average kinetic energy of the atoms in a substance.

The more kinetic energy a substance has, the greater its temperature is (and the faster its atoms are moving).

The less kinetic energy a substance has, the lower its temperature is (and the slower its atoms are moving).

Temperature and thermal energy are related, but they are not the same.

You can measure temperature with a thermometer.

In Science (and the Metric System), we measure temperature in either degrees Celsius or Kelvin.

• Fresh water freezes at 0 degrees Celsius, and boils at 100 degrees Celsius.

• Water freezes at 273 Kelvin and boils at 373 Kelvin.

• 0 Kelvin is the lowest possible temperature for any substance.  It is called absolute zero.

• At absolute zero, the atoms in a substance have no kinetic energy at all.

• Scientists have not yet been able to cool any substance to 0 Kelvin.

Heat is the movement of thermal energy from a warmer object to a cooler object.

The Second Law of Thermodynamics states that heat will naturally flow from a hotter object to a colder one, but will not naturally flow from a colder object to a hotter one.  

Newton’s Law of Cooling states that when one object is much hotter than another, it will transfer its heat quickly.  When one object is only slightly warmer than another, it will transfer heat to the cooler object much more slowly.  

Heat will continue to flow from a warmer object to a cooler object until both objects are the exact same temperature.

Summary:

• Events: The chapter introduces the concepts of thermal energy, temperature, and heat. It explains the differences between these terms and how they are related to each other. It also discusses the units of measurement for temperature and heat.

Main Themes and Motifs:

• Thermal Energy: The chapter emphasizes the importance of understanding thermal energy and its role in various processes.

• Temperature: The concept of temperature and its measurement are key themes, highlighting its significance in determining the hotness or coldness of an object.

• Heat: The discussion on heat focuses on its transfer mechanisms and how it affects the thermal equilibrium of a system.