What kinds of energy do you see?

Energy Transfer ICP

FTF Day 2 April 16, 2012 HW: none Topic: Light (last day) Questions: 1. When light passes through a prism, which colors of light are bent the most? 2. Which two colors of paint could you combine to make purple? 3. Which two colors of light could you combine to make yellow?

Vocabulary Types of energy Kinetic energy- Energy that something has because its moving. Thermal energy energy that something has because its hot (or not hot = little thermal E)

Potential energy stored energy. Often written as PE Chemical energy energy stored in bonds between atoms Gravitational energy energy stored in an object because of its position relative to the ground. (high up= lots of potential energy) How else can energy be stored?

Ways to Transfer Heat Conduction heat transferred from atom to atom (think of objects that are touching) Convection heat transferred because gasses or liquids are circulating Radiation heat lost or gained because of electromagnetic radiation (infrared, light, gamma, etc.) Latent Heat heat lost or gained when the object changes phase (gas to liquid, solid to liquid, etc.)

Reactions Endothermic a process that takes in thermal energy from its surroundings (products have more energy than the ingredients you started with.) Example - Exothermic a process that releases thermal energy to its surroundings (products have less energy than the ingredients you started with) Example-

Measuring thermal energy Calories or calories units for measuring the amount of energy in a substance. 1 calorie is the amount of energy it takes to heat 1 cm 3 of water up 1 degree Celsius. 1 Calorie = 1000 calories (capitol C is what you see on food packages) Calorimetry - the measuring of thermal energy in a system.

The Big Picture Law of conservation of energy Energy may neither be created nor destroyed. Therefore, the sum of all the energy in the system is a constant.

FTF Day 3 April 18, 2012 HW: Bring book to class tomorrow. Study for vocab quiz on Monday. Topic: Kinetic Energy Potential Energy Questions 1. What is the law of conservation of energy? 2. As the pendulum reaches the bottom of its arch, what happens to its speed? (Kinetic Energy) 3. As it reaches the bottom, what happens to its height? (Potential Energy)

Activities Phet lab: Skate Park Basics bit.ly/y7iucb

FTF Day 4 April 19, 2012 HW: BRING BOOK Tomorrow. Study for vocab quiz, Monday Topic: Energy Transfer Question: 1. The units for measuring energy are or. 2. Imagine you and your snowboard have 20 Joules of potential energy (PE) at the top of a hill. If you coast to the bottom of the hill, how much kinetic energy (KE) will you have? 3. What if, you measure the amount of energy you have at the bottom and it comes out to be less than 20. Where did the rest of the energy go?

Activities Phet Lab: Skate Park Basics

ICP: FTF Day 5 April 20, 2012 HW: Study for vocab quiz Monday Questions from book due today. Topic: PE KE Questions: At the top of the arc, the pendulum has 0 Joules of KE and 10 Joules of PE. At the bottom of the arc, the pendulum will have Joules of KE and Joules of PE.

Activities Book Work Read 6.3, 6.4, 6.5, and 6.7 Answer Pg

FTF Day (we didn t do this one yet) April?, 2012 HW: Topic: Potential, Kinetic, and Thermal energy Questions: 1. Why didn t the bucket hit the volunteer in the face? 2. The ATC slowed down the climber s decent. The climber s Kinetic Energy was transferred to energy due to friction between the rope and the ATC. (wait for pictures..)

ATC ATC stands for Air Traffic Controller.

http://www.youtube.com/w atch?v=yo4qsog7bc8

An egg being cooked in a pan

A cake being cooked in the oven

Icing a sprained ankle

Blowing on your hands to warm them or blowing on your soup to cool it.

A tanning booth works this way

Burgers on a gas grill.

A radiator circulates fluid through the engine to keep it cool.

A thermos insulates hot cocoa by preventing this kind of heat transfer.

The sun heats your car

A hair dryer works this way

FTF Day 6 April 26, 2012 HW: wear closed toad shoes Topic: Heat of vaporization, heat of fusion Question: Metabolism is the process of breaking down food so your body can utilize the energy stored in carbohydrates, proteins, and fats. Is metabolism endothermic or exothermic?

See PPT titled heat of fusion and vaporization for slides from today.

Melting and Freezing A substance is melting while it changes from a solid to a liquid. is freezing while it changes from a liquid to a solid. such as water has a freezing (melting) point of 0 C. Copyright 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings 35

Calculations Using Heat of Fusion The heat of fusion is the amount of heat released when 1 gram of liquid freezes (at its freezing point). is the amount of heat needed to melt 1 gram of a solid (at its melting point). for water (at 0 C) is 80. cal 1 g water 36

Calculation Using Heat of Fusion The heat needed to freeze (or melt) a specific mass of water (or ice) is calculated using the heat of fusion. Heat = g water x 80. cal 1 g water Example: How much heat in cal is needed to melt 15.0 g of water? 15.0 g water x 80. cal = 1200 cal 1 g water 37

Learning Check A. How many calories are needed to melt 5.00 g of ice at 0 C? 1) 80. cal 2) 400 cal 3) 0 cal B. How many calories are released when 25.0 g of water at 0 C freezes? 1) 80. cal 2) 0 cal 3) 2000 cal 38

Solution A. How many calories are needed to melt 5.00 g of ice at 0 C? 2) 400 cal 5.00 g x 80. cal 1 g B. How many calories are released when 25.0 g of water at 0 C freezes? 3) 2000 cal 25 g x 80. cal 1 g 39

Sublimation Sublimation occurs when particles change directly from solid to a gas. is typical of dry ice, which sublimes at -78 C. takes place in frost-free refrigerators. is used to prepare freezedried foods for long-term storage. 40

Evaporation and Condensation Water evaporates when molecules on the surface gain sufficient energy to form a gas. condenses when gas molecules lose energy and form a liquid. Copyright 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings 41

Heat of Vaporization The heat of vaporization is the amount of heat absorbed to vaporize 1 g of a liquid to gas at the boiling point. released when 1 g of a gas condenses to liquid at the boiling point. Boiling Point of Water = 100 C Heat of Vaporization (water) = 540 cal 1 g water 43

Learning Check How many kilocalories (kcal) are released when 50.0 g of steam from a volcano condenses at 100 C? 1) 27 kcal 2) 540 kcal 3) 2700 kcal 44

Solution How many kilocalories (kcal) are released when 50.0 g of steam in a volcano condenses at 100 C? 1) 27 kcal 50.0 g steam x 540 cal x 1 kcal = 27 kcal 1 g steam 1000 cal 45

Summary of Changes of State 46

Heating Curve A heating curve illustrates the changes of state as a solid is heated. uses sloped lines to show an increase in temperature. uses plateaus (flat lines) to indicate a change of state. Copyright 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings 47

Learning Check A. A flat line on a heating curve represents 1) a temperature change. 2) a constant temperature. 3) a change of state. B. A sloped line on a heating curve represents 1) a temperature change. 2) a constant temperature. 3) a change of state. 48

Solution A. A flat line on a heating curve represents 2) a constant temperature. 3) a change of state. B. A sloped line on a heating curve represents 1) a temperature change. 49

Cooling Curve A cooling curve illustrates the changes of state as a gas is cooled. uses sloped lines to indicate a decrease in temperature. uses plateaus (flat lines) to indicate a change of state. Copyright 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings 50

Learning Check Use the cooling curve for water to answer each. A. Water condenses at a temperature of 1) 0 C. 2) 50 C. 3) 100 C. B. At a temperature of 0 C, liquid water 1) freezes. 2) melts. 3) changes to a gas. C. At 40 C, water is a 1) solid. 2) liquid. 3) gas. D. When water freezes, heat is 1) removed. 2) added. 51

Solution Use the cooling curve for water to answer each. A. Water condenses at a temperature of 3) 100 C. B. At a temperature of 0 C, liquid water 1) freezes. C. At 40 C, water is a 2) liquid. D. When water freezes, heat is 1) removed. 52

Heat Calculations To reduce swelling, you put 250 g of ice on your sprained ankle. If the ice (at 0 C) melts and warms to body temperature (37.0 C), how many calories are removed from the body? 53

Heat Calculations To reduce swelling, you put 250 g of ice on your sprained ankle. If the ice (at 0 C) melts and warms to body temperature (37.0 C), how many calories are removed from the body? Step 1: Diagram the changes 37 C temperature increase 0 C solid liquid (melting) 54

Heat Calculations Step 2: How is the ice changing? (2 formulas) Ice is melting and then increasing in temperature from 0 to 37.0 C. Heat of fusion = g of ice x 80.0 cal 1 g ice Heat to increase temperature = g of ice x T x 1 cal Then add them together. 1 g/1 C 55

Step 3: Plug value into equations Heat = 250 g of ice x 80.0 cal = 20,000 cal 1 g ice Heat = 250 g of ice x 37 C 1 cal = 9,250 cal 1g/1 C Add them together: 20,000 + 9,250 = 29,250 calories = 29.25 Calories (Kcal) 56

FTF Day 7 April 30 2012 HW: Calorimetry lab due tomorrow, test on Wednesday Make a clues sheet Topic: calories /gram If it takes 1 calorie to raise the temperature of 1 gram of H20 by 1 degree celcius, How many calories are required to raise the temperature of 100 grams of water by 1 degree C? A tic-tac contains 2000 calories (2 Calories, or Kilocalories) of potential energy. If you used all those calories to raise the temp of 100 G of water, how much would the temperature increase?