Physics 1 Revision Lesson 2 Factors affecting cooling and Insulating buildings

Factors affecting cooling

As energy increases the probability of evaporation increases As pressure increases the probability of evaporation decreases

The larger the surface area, the faster the rate of cooling. This is because more of the object is exposed to the outside Large surface area Small surface area

The bigger the temperature difference, the faster the rate of cooling 40ºC 10ºC Here the liquid will cool down faster since there is a 30ºC difference between it’s temperature and the surroundings 40ºC 35ºC Here the liquid will cool down slowly since there is only a 5ºC difference between it’s temperature and the surroundings

Heating and Insulating buildings

Good insulators don’t allow heat to travel through them insulators do not have free electrons the lower the u value the better a material is at insulating the amount of heat required to heat something by 1ºC is called specific heat capacity

Key words and statements

Insulators U value Specific heat capacity Cooling Surface area Temperature difference Evaporation Condensation When a gas turns into a liquid because the atoms have lost energy When temperature decreases due to a loss of energy The amount of surface exposed to the outside When a liquid turns into a gas because the atoms have gained energy The difference between outside and inside temperature The amount of heat required to raise the temperature of an object by 1ºC A material with no free electrons and therefore doesn’t allow heat to pass easily through it A measurement of how much heat is lost through a material. A low u value mans that less heat is lost Factors affecting cooling and insulating buildings

Insulators U value Specific heat capacity Cooling Surface area Temperature difference Evaporation Condensation When a gas turns into a liquid because the atoms have lost energy When temperature decreases due to a loss of energy The amount of surface exposed to the outside When a liquid turns into a gas because the atoms have gained energy The difference between outside and inside temperature The amount of heat required to raise the temperature of an object by 1ºC A material with no free electrons and therefore doesn’t allow heat to pass easily through it A measurement of how much heat is lost through a material. A low u value mans that less heat is lost Factors affecting cooling and insulating buildings

A small temperature difference… A large u value means… The amount of heat needed to heat a substance by 1ºC is called… A small u value means… A smaller surface areas causes… A large temperature difference… Increased pressure causes decreased rate of evaporation because… Increased temperature increases rate of evaporation because… The particles are gaining energy at a faster rate, causing them to turn into a gas and evaporate more quickly That a material is a good conductor as more heat can pass through it Decreases the rate of heat loss Specific heat capacity The particles are being squashed together and they require more energy than usual to evaporate and turn into a gas That a material is a bad conductor but a good insulator because less heat can pass through it A decrease in heat loss because there is less area exposed to the outside. Increases the rate of heat loss Factors affecting cooling and insulating buildings

A small temperature difference… A large u value means… The amount of heat needed to heat a substance by 1ºC is called… A small u value means… A smaller surface areas causes… A large temperature difference… Increased pressure causes decreased rate of evaporation because… Increased temperature increases rate of evaporation because… The particles are gaining energy at a faster rate, causing them to turn into a gas and evaporate more quickly That a material is a good conductor as more heat can pass through it Decreases the rate of heat loss Specific heat capacity The particles are being squashed together and they require more energy than usual to evaporate and turn into a gas That a material is a bad conductor but a good insulator because less heat can pass through it A decrease in heat loss because there is less area exposed to the outside. Increases the rate of heat loss Factors affecting cooling and insulating buildings