Heat

• The temperature of an object is related to its average kinetic energy per particle.
• Heat is the transfer of thermal energy from one object to another.
• A thermometer is an instrument used to measure the temperature of an object.
• Conduction, convection, and radiation are three ways heat can be transferred between objects.
• Conduction occurs when heat is transferred between two solids in contact with each other.
• Some substances can conduct heat faster than others. Substances that easily transfer heat energy arecalled heat conductors.
• Some substances heat slowly and/or resist the transfer of heat energy. Substances that resist the transfer of heat energy are called heat insulators.
• Convection occurs when heat is transferred between two liquids or gases. 
• Convection relies on density of the fluid.
• Radiation occurs when heat is emitted from any heat source in the form of an invisible electromagnetic wave.
• Heat carried by radiation is known as infrared radiation.
• Radiation transfers heat by waves, not particles like conduction

  or convection. This means that it can travel through the vacuum of space. 
• Dark surfaces absorb a lot of radiation. 
• Light coloured surfaces do not absorb most radiation.
• Clear objects like glass, do not reflect or absorb heat

  radiation. Instead they transmit the radiation. This means that radiation passes through the object.
• Heat energy is measured in joules (J) or kilojoules (kJ).
• A hotter object will radiate more heat than a cooler one.
• convection currants are caused by the movement of warm air over cooler air, causing the air to rise and cool
• particles that are heated up move faster and have more energy than particles that are not heated up
• the phase change between a solid and a liquid is called melting and the phase change between a liquid and a gas is called boiling
• the phase change between a solid to a gas is called sublimation
• the phase change between a gas to a solid is deposition
• gas to a liquid is condensation
• absolute 0 means the temperature is 0 degrees celsius and there is no heat energy
• All substances are made of matter
• As matter moves from a solid to a liquid to a gas, its properties become more variable and less definite
• Particles with more energy


  Are better able to overcome the attractions between them, resulting in weaker bonds
• Gases have a variable volume


  Because their particles are far apart and can expand and be compressed
• In liquids and gases

  Particles can move past one another, giving them a variable shape
• Matter is made of particles
• Particles with strong bonds and in a low energy state

  Cannot move around freely, as seen in solids where particles can only vibrate
• Particles


  Tiny units attracted to one another and constantly moving
• Strong bonds


  Hold particles close together, making solids and liquids incompressible
• Change in properties


  Caused by a change in the energy state of the particles
• Insulators have strong bonds that hold their particles rigidly in place. Since particles in an insulator don't move around easily, the amount of energy that is transferred to other particles is minimal.
• Conductors have weaker bonds between their particles than insulators do. This means that when heat is applied to conductors, more energy is transferred from particle to particle, causing them all to vibrate faster.