Energy

Unit Review Sheet

Facts and Definitions

Lesson 1: What Is Energy?

• Energy is the ability to do work.
• A newton is a unit used to measure force.
• A joule is a unit used to measure work.
• Potential energy is stored energy that is waiting to be used.
• Kinetic energy is the energy of a moving object.
• Work = force × distance

Lesson 2: Electricity

• Batteries store energy that can be used for motion and light.
• Fossil fuels are nonrenewable sources of energy, such as coal, oil, and natural gas. They are formed from the remains of plants and animals that have been buried beneath the surface of the earth and changed by heat and pressure.

Lesson 3: Light

• When white light is split, it makes a rainbow.
• Light travels in waves.
• The primary colors of light are red, green, and blue.
• Reflection of light occurs when light bounces off a surface.
• Absorption of light occurs when light is taken in and not reflected off a surface.
• Refraction is the bending of light as it travels through a transparent surface.

Lesson 4: Heat and the Sun

• Thermodynamics is a branch of science that focuses on heat and how it is related to work, energy, temperature, and matter.
• The first law of thermodynamics states that energy cannot be created or destroyed, but it can be changed.
• The second law of thermodynamics states that energy always moves from hot things to cold things.
• The third law of thermodynamics states that nothing can be colder than absolute zero (-276.16 degrees C / - 459.67 degrees F).
• The Sun's energy can be used to do work and to heat our homes.

Lesson 5: Chemical Energy

• An atom is the smallest component of an element and is made up of protons, neutrons, and electrons.
• An element is a substance made up of one type of atom.
• A molecule is formed when two or more atoms are bonded chemically. The atoms can be the same element or they can be different. These atoms can be the same element (like O₂ or H₂) or different elements (like H₂O or CO₂).
• A compound is a molecule made up of two or more elements. All compounds are molecules, but not all molecules are compounds. Example: O₂ (oxygen gas) is a molecule, but it is not a compound because it contains only one element. H₂O (water) is both a molecule and a compound because it contains two different elements (hydrogen and oxygen).
• Scientists have another name for the first law of thermodynamics: the law of conservation of mass-energy.
• An exothermic reaction is a chemical reaction that releases energy in the form of heat and/or light.
• In an endothermic reaction, energy is taken in and is transformed into chemical bond energy.

Lesson 6: Food and Energy

• Through photosynthesis, plants convert light energy from the Sun into chemical energy.
• Energy is passed from one organism to another in a food chain.
• A calorie (aka, a small calorie) is the amount of energy, or heat, it takes to raise the temperature of 1 gram of water 1 degree Celsius.

Final Project: Energy Test

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