Thermal Energy Define the following terms and/or concepts Study - PDF document

Slide 1 / 67 Slide 2 / 67 8th Grade Thermal Energy Study Guide 2015-10-09 www.njctl.org Slide 3 / 67 Slide 4 / 67 Part 1 Thermal Energy Define the following terms and/or concepts Study Guide www.njctl.org Slide 5 / 67 Slide 6 / 67 1 Temperature 2 Kinetic Energy

Slide 7 / 67 Slide 8 / 67 3 Thermal expansion 4 Thermal contraction Slide 9 / 67 Slide 10 / 67 5 Potential Energy (between molecules) 6 Thermal Energy Slide 11 / 67 Slide 12 / 67 7 Heat 8 Thermal Equilibrium

Slide 13 / 67 Slide 14 / 67 9 Conduction 10 Radiation Slide 15 / 67 Slide 16 / 67 11 Convection 12 Conductors Slide 17 / 67 Slide 18 / 67 13 Insulators 14 Specific heat

Slide 19 / 67 Slide 20 / 67 15 Thermodynamics 16 Work Slide 21 / 67 Slide 22 / 67 17 1st law of thermodynamics 18 2nd law of thermodynamics Slide 23 / 67 Slide 24 / 67 19 entropy 20 heat engine

Slide 25 / 67 Slide 26 / 67 21 When a liquid is cooled, the liquid molecules A spread farther apart. Part 2 B move slower than before. Directions: Select the answer choice that best C experience thermal contraction. completes the statement or answers the question. D increase their kinetic energy. Slide 27 / 67 Slide 28 / 67 22 This type of heat transfer can occur in outer 23 An insulator is a material that has molecules that space. A are closely packed together. A Conduction B move easily past one another. B Convection C do not transfer heat easily. C Radiation D will shrink when heated. D Entropy Slide 29 / 67 Slide 30 / 67 24 The following objects are all heated from 10°C to 25 Two objects of the same material but different 30°C. Which object will transfer the most energy masses are subjected to the same thermal energy to your hand? input. A The object with less mass will experience a greater A 5kg apples change in temperature. B 2kg apples B The object with more mass will experience a greater change in temperature. C 5kg gold C They will both experience the same change in D 2kg gold temperature. D It is impossible to compare their changes in temperature without knowing the specific heat of the objects.

Slide 31 / 67 Slide 32 / 67 26 All of the following are examples of conductors 27 A 80°C object and a 60°C object sit (not touching) except in a 21°C environment. Which best explains what will happen. A Silver A Both objects will get warmer. B Water B The warmer object will exchange heat with the C Air environment at a slower rate. D Aluminum C The environment will get warmer. D The warmer object will cool down while the cooler object will stay the same temperature. Slide 33 / 67 Slide 34 / 67 28 An example of heat transfer by convection is 29 Which of the following is an example of energy conservation? A touching a hot pan and burning your finger A An apple hangs suspended from a tree. B water boiling in a pot on the stove B A person stands on tiptoes. C feeling the warmth of a campfire on your face C A car waits at a red light. D A hockey puck slides to a stop due to friction. D the sun warming the roof of a house Slide 35 / 67 Slide 36 / 67 30 When energy is transferred as heat, the amount of useable energy A decreases. Part 3 B remains the same. Directions: Answer the following thoroughly. A C increases. table of specific heats is attached. D is always zero.

Slide 37 / 67 Slide 38 / 67 31 How are temperature and kinetic energy related? Substance Specific Heat (J/kg °C) Aluminum 897 Apples 3,300 Bricks 800 Carbon 709 Copper 385 Gold 129 Iron 449 Mercury 140 Steam 1,870 Tin 230 Water 4,186 Wood 1,700 Slide 39 / 67 Slide 40 / 67 32 Describe what happens to motion and spacing of 33 What does a thermometer measure? molecules when heated or cooled for a: A liquid B solid C gas Slide 41 / 67 Slide 42 / 67 35 Complete the following conversions: 34 Describe characteristics of the three temperature scales including freezing and boiling point of water for each. A 37 ° C to Fahrenheit B 384 Kelvin to degrees Celsius C -45 ° C to Kelvin D 45 ° F to degrees Celsius

Slide 43 / 67 Slide 44 / 67 36 Using the ideas of thermal expansion and 37 Recall the video shown in class of the bimetallic contraction, describe how a liquid thermometer strip that was bent when it was heated. Explain works. why it bent. (HINT: remember that the strip was made of two different metals) Slide 45 / 67 Slide 46 / 67 38 When does potential energy between molecules 39 What two types of energy do molecules possess? increase? Decrease? Slide 47 / 67 Slide 48 / 67 40 Explain why thermal energy and temperature, 41 Provide an example of when two substances though related, are different. might have the same temperature but different thermal energy.

Slide 49 / 67 Slide 50 / 67 42 Which will cool fastest initially in a room 43 How are heat flow and temperature differences temperature room? Boiling water or lukewarm related? water? Slide 51 / 67 Slide 52 / 67 44 Will heat flow between two objects touching that 45 Which direction does heat flow? Give an example. have the same temperature? Why or why not? Slide 53 / 67 Slide 54 / 67 46 What are the three methods of thermal energy 47 Do all objects emit the same amount of radiation? transfer? Give a couple of examples of each. Why or why not?

Slide 55 / 67 Slide 56 / 67 48 Conduction occurs primarily in solids. Why? 49 What is the primary difference between conductors and insulators? Slide 57 / 67 Slide 58 / 67 50 Give several examples of conductors and 51 If you wanted water to boil quickly in a tea kettle, insulators. what kind of material would you use for the tea kettle? Slide 59 / 67 Slide 60 / 67 52 If you wanted to maximize heat transfer, what 53 If you have several spoons made of conducting kind of material would you use? How about if you materials and insulating materials, which will feel wanted to minimize heat transfer? cooler to the touch and why?

Slide 61 / 67 Slide 62 / 67 55 State whether the variable is “inversely” or 54 Suppose you took a bite of pie that was at a “directly” proportional to the temperature change. certain temperature. The crust doesn’t burn you Provide an illustrative example for each. but the filling does. Using the idea of specific heat, explain why the filling burned you but the crust didn’t even though they had the same A mass temperature. B specific heat C thermal energy transferred Slide 63 / 67 Slide 64 / 67 56 Calculate the heat input (or output) required to 57 Calculate the final temperature of 0.020 kg of change the temperature of 3kg of iron by 3 mercury that loses 500J of thermal energy and degrees Celsius. started with a temperature of 400Kelvin. Slide 65 / 67 Slide 66 / 67 58 Calculate the change in temperature of 10kg of 59 Give an example of the 1st law of wood that gains 3,000J of thermal energy. thermodynamics in action.

Slide 67 / 67 60 What energy conversions are involved in a heat engine?