Gravitational potential energy when force that you use against force of gravity

Mechanical energy the amount of work an object can do because of the object’s kinetic and potential energies

Thermal energy is all of the kinetic energy due to random motion of the particles that make up an object

Chemical energy is a form of potential energy because it depends on the position and arrangement of the atoms in a compound

Sound energy is caused by an object’s vibrations

Light energy i s produced by the vibrations of electrically charged particles

Nuclear energy the energy that comes from changes in the nucleus of an atom

Section 2 Energy Conversions

Energy conversion a change from one form of energy to another

Radiometer device that was invented to measure energy from the sun, change the light energy into kinetic energy

Section 3 Conservation of Energy

Friction a force that opposes motion between two surfaces that are in contact

Closed system is a group of objects that transfer energy only to each other

Law of conservation of energy the law that states that energy cannot be created or destroyed but can be changed from one form to another

Energy efficiency is a comparison of the amount of energy after a conversion with the amount of useful energy after conversion

Section 4 Energy Resources

Energy resource is a natural resource that can be converted into other forms of energy in order to do useful work

Nonrenewable resource a resource that forms at a rate that is much slower than the rate at which it is consumed

Fossil fuel a nonrenewable energy resource formed from the remains of organisms that lived long ago

Electrical generators convert the chemical energy in fossil fuels into electrical energy

Nuclear fission is process when the nucleus of a radioactive element(uranium,…) is split into two smaller nuclei, which releases nuclear energy

Renewable resource a natural resource that can be replaced at the same rate at which the resource is consumed

Geothermal energy is thermal energy caused by the heating of Earth’s crust

Biomass organic matter such as plants, wood, and waste, that can be burned to release energy

Chapter 10 Heat and Heat Technology

Section 1 Temperature

Temperature a measure of how hot(or cold) something is; specifically, a measure of the average kinetic energy of the particles in an object

Thermal expansion an increase in the size of a substance in response to an increase in the temperature of the substance

Absolute zero the temperature at which molecular energy is at a minimum(0 K on the Kelvin scale or -273.16 C on the Celsius scale)

Expansion joints small gaps that make sound when car go through them

Bimetallic strip used in some thermostats, made of two different metals stacked in a thin strip

Section 2 What is Heat?

Heat the energy transferred between objects that are at different temperatures

Thermal energy the kinetic energy of a substance’s atoms, measured in joules(J)

Thermal conduction the transfer of energy as heat through a material

Thermal conductors a material through which energy can be transferred as heat

Thermal insulator a material that reduces or prevents the transfer of heat

Convection the transfer of thermal energy by circulation or movement of a liquid or gas

Convection current circular motion of liquids or gases doe to density differences that result from temperature

Radiation the transfer of energy as electromagnetic waves

Greenhouse effect is process in which visible light passes through the atmosphere and heats Earth(1), Earth radiates infrared waves, some of which escape into space(2), greenhouse gases trap some of the reradiated energy near earth’s surface(3)

Thermal conductivity is the rate at which a substance conducts thermal energy

Specific heat the quantity of heat required to raise a unit mass of homogeneous material 1 K or 1 C in a specified way given constant pressure and volume

Section 3 Matter and Heat

States of matter the physical forms of matter, which include solid, liquid, and gas

Change of state the change of a substance from one physical state to another

Freezing (liquid to solid), melting (solid to liquid), boiling (liquid to gas), and condensing (gas to liquid)

Chemical changes changed that occur when one or more substances are changed into entirely new substances that have different properties

Calorimeter is device that measures heat

Section 4 Heat Technology

Insulation is substance that reduce the transfer of electricity, heat, or sound

Passive solar heating a building takes advantage of the sun’s energy without use of moving parts

Active solar heating uses moving parts to aid the flow of solar energy throughout a building

Heat engine a machine that transforms heat into mechanical energy, or work

Combustion when heat engines burn fuel through combine fuel with oxygen in a chemical change that releases thermal energy

Combustion engines heat engines that burn fuel outside the engine

Internal combustion engines heat engines that burn fuel inside the engine

Intake stroke a mixture of gasoline and air enters each cylinder as the piston moves down

Compression stroke the crankshaft turns and pushes the piston up, compressing the fuel mixture

Power stroke spark plug uses electrical energy to ignite the compressed fuel mixture. As the mixture of fuel and air burns, it expands and forces the piston down

Exhaust stroke the crankshaft turns, and the piston forced back up, pushing exhaust gases out of the cylinder

Compressor device used electrical energy, does the work of compressing the refrigerant

Refrigerant is gas that has a boiling point below room temperature, which allows it to condense easily

Thermal pollution a temperature increase in a body of water that is caused by human activity and that has a harmful effect on water quality and on the ability of that body of water to support life

Unit 4 The Atom

Chapter 11 Introduction to Atoms

Section 1 Development of the Atomic Theory

Atom the smallest unit of an element that maintains the properties of that element

Electron a subatomic particle that has a negative charge

Nucleus in physical science, an atom’s central region, which is made up of protons and neutrons

Electron cloud a region around the nucleus of an atom where electrons are likely to be found

Section 2 The Atom

Protons a subatomic particle that has positive charge and that is found in the nucleus of an atom

Atomic mass unit of mass that describes the mass of an atom or molecule(symbol, amu)

Neutron a subatomic particle that has no charge and that is found in the nucleus of an atom

Ion atom that becomes a charged particle

Atomic number the number of protons in the nucleus of an atom; the atomic number is the same for all atoms of an element

Isotope an atom that has the same number of protons as other atoms of the same element do but that has a different number of neutrons

Unstable atom (isotope) is an atom with a nucleus that will change over time, unstable isotopes is radioactive

Mass number the sum of the numbers protons and neutrons in the nucleus of an atom

Atomic mass the mass of an atom expressed in atomic mass units

Chapter 12 The Periodic Table

Section 1 Arranging the Elements

Periodic describes something that occurs or repeats at regular intervals

Periodic law the law that states that the repeating chemical and physical properties of elements change periodically with the atomic numbers of the elements

(most) Metals shiny, malleable, ductile, good conductors of electric current, good conductors of thermal energy

Nonmetals not malleable or ductile, not shiny, poor conductors of thermal energy and electrical current

Metalloids shiny, but brittle, they have some properties of metals and nonmetals, metalloids also called semiconductors

Period in chemistry, a horizontal row of elements in the periodic table

Group a vertical column of elements in the periodic table; elements in a group share chemical properties

Section 2 Grouping the Elements

Alkali metal one of the elements of Group 1 of the periodic table(lithium, sodium, potassium, rubidium, cesium, and francium)

Alkaline-earth metal one of the elements of Group 2 of the periodic table(beryllium, magnesium, calcium, strontium, barium, and radium)

Halogen one of the elements of Group 17 of the periodic table(fluorine, chlorine, bromine, iodine, and astatine); halogens combine with most metals from salts

Noble gas one of the elements of group 18 of the periodic table(helium, neon, argon, krypton, xenon, and radon); noble gases are unreactive

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