L.O: SWBAT explain what specific heat and water changes phase when it gains or releases heat energy.

On a summer day, why is a sandy beach hot, but the ocean is STILL COLD?

How quickly will a substance heat up? Every substance requires a different amount of heat energy to change temperatures. The quantity of heat required to raise the temperature of one gram of a substance by a temperature of one degree Celsius is known as the specific heat.

As the specific heat increases the time needed to change temperature increases because more heat is required. Objects with a HIGH specific heat will take really long time to heat up and cool down Objects with a LOW specific heat will heat up and cool down

The Specific Heats of Common Materials chart on page one of your ESRT gives you information about important materials on Earth. What is the unit used for specific heat? _________________ What is the material with the highest specific heat? _________________ What is the material with the lowest specific heat? _________________ Which material will heat up the fastest? _________________ Which material will heat up the slowest? _________________

On the regents you’ll be asked why does the land heat up quicker than the water.

Answer: the land is made of materials that have a low specific heat, so they heat up fast. Water has a high specific heat. It takes a long time to heat up

Materials with a low specific heat (land), heat up fast and get cold fast.

Materials with a high specific heat (water), heat up slowly and get cold slowly.

Deserts are very hot in the day and very cold at night Deserts are very hot in the day and very cold at night! Low specific heat materials heat up fast and lose the heat fast..

Oceans are often cold in summer but warm in winter because they take a long time to heat up & a long time to cool down.

What happens when a material gains or loses heat? If enough heat is given or taken away from a material it will go through a phase change.

Phase changes that require the addition of heat: Melting – solid to liquid Evaporation/vaporization – liquid to gas Sublimation – solid to gas

Phase changes that require the removal of heat: Condensation – gas to liquid Freezing – liquid to solid Deposition – gas to solid

page 1 shows the joules of energy to change water’s phase. A Joule is a measure of heat energy.

liquid water is more dense than ice liquid water is more dense than ice. Water is densest at 40 C, when it is liquid.

334 joules/gram must be released to Freeze water.

334 joules/gram must be gained to melt ice.

2260 J/g must be gained to turn liquid water to water vapor.

2260 J/g must be released to turn water vapor to liquid.

ice Liquid water Water vapor 2260 joules/gram 334 joules/gram

if 334 joules is needed to melt one gram of ice, how much is needed to melt TWO grams? To melt 2 grams of ice, 668 joules is needed. (2 x 334= 668 joules) Water vapor (gas) ice Liquid water 2260 J/g 334 J/g

22,600 joules of energy is needed to boil water into gas. 10 x 2260 = 22,600 joules liquid water gains 2260 joules/gram to become gas. How much energy is needed to vaporize 10 grams of water? Water vapor (gas) ice Liquid water