I. What is Energy? II. Types of Energy Energy is the ability to do work or cause change. II. Types of Energy Electrical Sound Light Chemical Heat or Thermal Mechanical Nuclear

A. Kinetic Energy B. Potential Energy Kinetic Energy is the energy of motion Particles with a lot of kinetic energy move fast and far apart Particles with little kinetic energy move slow & close together Particles with a lot of kinetic energy B. Potential Energy Potential Energy is the energy waiting to be used It is the attractive force of gravity between Earth that gives objects potential energy Molecules exert attractive forces on each other Particles with little kinetic energy

How do mercury thermometers work? C. Temperature Temperature is the average kinetic energy of the individual particles in a substance So… if it is hot more kinetic energy, if cold less kinetic energy. How do mercury thermometers work?

Absolute zero Farenheit Celsius Kelvin German physicist, Daniel Farenheit in 1724 Celsius Anders Celsius in 1742 Kelvin Lord Kelvin in 1848 Absolute zero Sometimes the claim is made that at absolute zero all molecular motion stops. In fact, at absolute zero molecules still have vibrational energy known as zero point energy.

D. Word Problems A students body temperature is 98.6 °F. What is the temperature in celsius? In Kelvin? A temperature of 57 °C was recorded in Death Valley, California. What is this temperature on the Fahrenheit scale? In Kelvin? °C= (98.6-32) =37 °C 1.8 K = 37 °C + 273 = 310K °F= 1.8 (57) + 32 =134.6 °F K= 57 °C + 273 = 330K

III. Thermal Energy The TOTAL (PE + KE) energy of all the particles in a sample of matter is called thermal energy. When transferred, it always moves from warmer to cooler objects by Conduction Radiation Convection

A. Heat Heat vs Thermal energy The movement of thermal energy from a substance at a higher temperature to one at a lower temperature is called heat. 3 ways to transfer: Heat vs Thermal energy

Occurs rapidly and most easily in solids and liquids 1. Conduction Transfer of thermal energy by direct contact Occurs when the particles in a material collide with neighboring particles, but do not move! Occurs rapidly and most easily in solids and liquids

2. Radiation Transfer of thermal energy by electromagnetic waves Can travel through empty space, as well as matter

Convection Lab 3. Convection Transfer of thermal energy by movement of atoms or molecules from one part of a material to the other Water heats by convection, warm water on bottom is less dense than cooler water on top so it rises until all water in pot is same temperature Convection Lab

B. Conductors C. Insulators Any material that easily transfers thermal energy Best conductors are gold and copper C. Insulators Any material in which thermal energy doesn’t flow easily Liquids and gases are best insulators, especially air

Law of Conservation of Energy The total amount of energy doesn’t change, it transfers from one form to the other.

State Change Pyramid Gas Liquid Solid Absorbing Releasing thermal energy Releasing thermal energy Gas Liquid Solid

State Change Pyramid Gas Liquid Solid Melting Absorbing Releasing thermal energy Releasing thermal energy Gas Melting Liquid Solid

Melting The change from the solid state to the liquid state is melting. The temperature at which a substance changes from a solid to a liquid is called the melting point. Melting is when matter absorbs thermal energy, and its temperature rises.

State Change Pyramid Gas Liquid Solid Melting Freezing Absorbing thermal energy Releasing thermal energy Gas Melting Freezing Liquid Solid

Freezing The change from the liquid state to the solid state is called freezing. The temperature at which a substance changes from the liquid state to the solid state is called the freezing point. Energy is released during freezing. .

State Change Pyramid Gas Liquid Solid Vaporization Melting Freezing Absorbing thermal energy Releasing thermal energy Gas Vaporization Melting Freezing Liquid Solid

Vaporization The change from a liquid to a gas is known as vaporization. The substance absorbs thermal energy.

Evaporation Evaporation, which occurs at temperatures below the boiling point, explains how puddles dry up. It takes more than speed for water molecules to escape the liquid state.

State Change Pyramid Gas Liquid Solid Condensation Vaporization Absorbing thermal energy Releasing thermal energy Gas Condensation Vaporization Melting Freezing Liquid Solid

Condensation As a gas cools, its particles slow down. When particles move slowly enough for their attractions to bring them together, droplets of liquid form.

State Change Pyramid Gas Liquid Solid Condensation Sublimation Absorbing thermal energy Releasing thermal energy Gas Condensation Sublimation Vaporization Melting Freezing Liquid Solid

Sublimation Some substances can change from the solid state to the gas state without ever becoming a liquid. During this process, known as sublimation, the surface particles of the solid gain enough energy to become a gas. Picture from http://www.ehow.com/how_2098268_fogsmoke-dry-ice-halloween.html