TOPIC: Heat AIM: How does heat affect molecules? Date # Assignment Mon Tues 12 Textbook page 259 #2,3,4 Wed 13 Textbook page 265 # 1,2,3 Thurs 14 Textbook page 270 # 1-4 Fri 15 Textbook page 282 # 1-13 Write out questions

Molecules Tiny particles that make up matter

Example: 1 molecule of water = H2O 5 molecules of water

Molecules are always moving which produces heat The more heat that is contained the faster the molecules move

HEAT Energy caused by the internal motion of molecules (friction) Energy moves from warm areas to areas that are cooler

Kinetic Theory of Matter Matter is made of molecules that are always in motion which collide & transfer their Kinetic Energy

Temperature The amount/quantity of heat an object contains Measure of average Kinetic energy of molecules

Analyzing relationships If heat is added to an object the molecules move ________, which _________ the Kinetic Energy, which causes the temperature to _________. faster increases increase

Low temp = slower moving High temp = fast moving

FASTER

70°F 70°F The pail of water has fewer molecules in it than the ocean does. Even though they may be the same temperature, the pail of water has less heat than the ocean.

The __________________ Instrument used For measuring Temperature is The __________________ thermometer

Heated Liquid level rises Cooled Liquid level drops

Thermal Expansion Increase in size of a substance caused by heat Temp increases makes molecules move faster & farther apart

Spaces between the joints allow the metals in the bridge to expand.

Hot air balloons rise because heated air expands

Fahrenheit Scale °F Non-metric temperature scale

Fahrenheit Facts Water freezes = 32°F Water boils = 212°F Human body temp = 98.6°F

°C Celsius Scale Metric temperature scale

Celsius Facts Water freezes = 0°C Water boils = 100°C Human body temp = 37°C

Kelvin Scale °K Metric temperature scale Units = Kelvins

Kelvin Facts Absolute Zero = 0K when molecules stop moving Only exists in space

Conversions °C  K Celsius + 273K

K  °C Kelvin - 273

400 – 273 = 127 °C Example 400K ? °C

56 + 273 = 329K Example: 56°C = ? K

CALORIES unit of heat 1 calorie = 4.184 J How is heat measured? CALORIES unit of heat 1 calorie = 4.184 J Amount of heat needed to raise the temp of 1g of water 1°C

1000 calories (1 kilocalorie) = 1 food Calorie

Your body uses the calories in food for heat and energy Your body uses the calories in food for heat and energy. Some foods contain more calories than others, and therefore provide your body with a concentration of energy. Foods that are high in calories contain large amounts of chemical energy, often more than your body can properly break down and use. What's left over is often stored as fat. That's why people on diets avoid foods that are high in calories.

When both ball and ring are at room temperature, the ball fits through the ring. When the ball is heated, it no longer fits due to thermal expansion.