FOCUS ON EARTH SCIENCE (6)

Thermal Energy and Heat /…iÊ Ê`i> Thermal energy moves from warmer to cooler materials until the materials have the same temperature 3.a ˆ} *ˆVÌÕÀi `i> Forms of Energy LESSON >ˆ˜ >ˆ˜Ê`i> Energy exists in,i>`ˆ˜} many forms …iVŽ 3.a, 3.b Energy Transfer LESSON >ˆ˜Ê`i> Energy can be transferred ˆ} from one >ˆ˜ *ˆVÌÕÀi place `i> to another ,i>`ˆ˜} LESSON …iVŽ3 3.a, 7.c Temperature, Thermal Energy, and ˆ}Heat >ˆ˜ *ˆVÌÕÀi `i> >ˆ˜Ê`i> Thermal energy flows from areas ,i>`ˆ˜} of higher …iVŽtemperature to areas of lower temperature 3.c, 3.d, 7.a ˆ} >ˆ˜ Conduction, *ˆVÌÕÀi `i> LESSON Convection, and ,i>`ˆ˜} Radiation …iVŽ >ˆ˜Ê`i> Thermal energy is transferred by conduction, convection, and radiation Feeling The Burn This raging forest fire glows red as it burns the trees and other vegetation in its path The changes caused by a forest fire are due to the release of thermal energy The thermal energy released by the fire causes the high temperatures that help keep the fire going -Vˆi˜ViÊÊ+PVSOBM List three changes that occur when you light a match ˆ} >ˆ˜ 120 *ˆVÌÕÀi `i> Tom J Ulrich/Visuals Unlimited ,i>`ˆ˜} …iVŽ Start-Up Activities How cold is it? Hot and cold are words you often use How accurate is your sense of hot and cold? Energy and Change Make the following Foldable to record the types of energy and examples of changes caused by the energy STEP Fold a sheet of paper into thirds lengthwise Procedure Complete a lab safety form Fill a pan with lukewarm water Fill a second pan with cold water and ice Fill a third pan with warm tap water Put one hand into the cold water and the other hand into the warm water Keep your hands in the water for 15 s Quickly remove both hands from the pans and put them both into the pan of lukewarm water Think about This STEP Unfold and draw vertical lines along the folds Draw three horizontal lines to divide the paper into four rows Label as shown ˜iÀ}Þ Ý>“«i Ý>“«i £ Ó • Identify which hand felt warmer when you placed both hands in the lukewarm water • Explain whether your sense of warm and cold would make a useful thermometer 3.a ELA6: R 2.4 Inferring As you read this chapter, list in the first column the types of energy discussed In the second column, list an example from the text of a change caused by that energy In the third column, describe a different change that you know is caused by that type of energy Visit ca6.msscience.com to: ▶ ▶ ▶ ▶ view explore Virtual Labs access content-related Web links take the Standards Check 121 Matt Meadows Get Ready to Read New Vocabulary ELA6: R 1.3 Learn It! What should you if you find a word you don’t know or understand? Here are some suggested strategies: Use context clues (from the sentence or the paragraph) to help you define it Look for prefixes, suffixes, or root words that you already know Write it down and ask for help with the meaning Guess at its meaning Look it up in the glossary or a dictionary Practice It! Look at the word bonds in the following passage See how context clues can help you understand its meaning Context Clue Bonds occur between atoms Context Clue Bonds join atoms together When you eat, you take in another type of potential energy Chemical potential energy is the energy stored in bonds between the atoms that make up matter Remember that atoms are joined together by chemical bonds to form molecules, as shown in Figure Chemical potential energy can be released during chemical reactions when these bonds are broken and new bonds are formed —from page 128 Context Clue Bonds can be broken Apply It! Make a vocabulary bookmark with a strip of paper As you read, keep track of words you not know or want to learn more about 122 Target Your Reading Use this to focus on the main ideas as you read the chapter Before you read the chapter, respond to the statements tainaph r g a r a m p Read a word fro y r a l u b ca go ing a vo d Then, n e o t g n e beginni mine th r e t e d o back t the word f o g n i n mea below on your worksheet or on a numbered sheet of paper • Write an A if you agree with the statement • Write a D if you disagree with the statement After you read the chapter, look back to this page to see if you’ve changed your mind about any of the statements • If any of your answers changed, explain why • Change any false statements into true statements • Use your revised statements as a study guide Before You Read A or D Statement After You Read A or D Energy is the ability to cause change There is only one type of energy Thermal energy always flows from larger objects to smaller objects Only waves can transfer energy from place to place Thermal energy from the Sun travels to Earth as waves Energy can be stored in a stretched rubber band Print a worksheet of this page at ca6.msscience.com Objects must be touching each other in order for energy to flow from one to another A baseball player can transfer energy to a baseball by hitting the ball with a bat Most materials get smaller when they are heated 10 The atoms and molecules in an object move slower as the object cools 123 LESSON Science Content Standards 3.a Students know energy can be carried from one place to another by heat flow or by waves, including water, light and sound waves, or by moving objects Reading Guide ▼ What You’ll Learn Define energy ▼ Describe different forms of energy ▼ Distinguish between kinetic energy and potential energy Why It’s Important Energy is the cause of all the changes you observe in the world around you Vocabulary energy kinetic energy potential energy elastic potential energy thermal energy Review Vocabulary gravity: attractive force between two objects that depends on the masses of the objects and the distance between them (Grade 5) 124 Chapter Runk/Schoenberger/Grant Heilman Photography Forms of Energy >ˆ˜Ê`i> Energy exists in many forms Real-World Reading Connection A pizza fresh from the oven sure smells good! When you put it in the oven, it was just soft dough covered with cold tomato sauce, cheese, and uncooked vegetables Now, the dough is crisp and golden, the sauce is hot, and the vegetables are toasted What caused ˆ}changes? >ˆ˜ these `i> *ˆVÌÕÀi What ,i>`ˆ˜}is energy? …iVŽ Think about the changes you see and feel every day You might have seen cars moving and felt the wind All the changes around you are caused by energy Energy (EN ur jee) is the ability to cause change There are different forms of energy The ball shown in Figure changes the window from a solid sheet of glass to many smaller glass pieces These changes occur because the moving ball has energy Kinetic (kuh NEH tihk) energy is the energy an object has because it is moving The amount of kinetic energy a moving object has depends on two things One is the object’s mass The other is the object’s speed The kinetic energies of some moving objects are given in Figure Figure The kinetic energy carried by the moving baseball caused this window to change Visualizing Kinetic Energy Figure ▲ The amount of kinetic energy of a moving object depends on the mass and speed of the object Energy is measured in units called joules (J) For example, the fastest measured speed a baseball has been thrown is about 45 m/s The kinetic energy of a baseball traveling at that speed is about 150 J ▼ A 600-kg race car traveling at about 50 m/s has about 5,000 times the kinetic energy of the baseball ▼ Earth’s atmosphere is continually bombarded by particles called cosmic rays, which are mainly high-speed protons The mass of a proton is about a 100 trillion trillion trillion times smaller than the mass of the baseball Yet some of these particles travel so fast, they have nearly the same kinetic energy as the baseball ▲ ▲ There is evidence that a meteorite 10 km in diameter collided with Earth about 65 million years ago and might have caused the extinction of dinosaurs The meteorite might have been moving 400 times faster than the baseball and would have a tremendous amount of kinetic energy due to its enormous mass and high speed—about a trillion trillion joules A sprinter with a mass of about 55 kg running at m/s has kinetic energy about 15 times greater than the baseball Contributed by National Geographic Lesson • Forms of Energy 125 (tl)Eleanor Kish/Canadian Museum of Nature, (tr)W Cody/CORBIS, (bl)Duomo/CORBIS, (br)William Swartz/Index Stock/PictureQuest Kinetic Energy and Speed ACADEMIC VOCABULARY occur (uh KUHR) (verb) to happen Something exciting occurred today In a game of pool, the cue ball hits the rack of balls and causes these balls to move The kinetic energy of the moving cue ball changes the positions and the motions of these other balls when it hits the rack A greater change occurs when the cue ball is moving faster Then the balls in the rack move faster and become more spread out This means that the cue ball has more kinetic energy when it is moving faster The faster an object moves, the more kinetic energy it has Kinetic Energy and Mass The kinetic energy a moving object has increases as the mass of the object increases Suppose you roll a volleyball down a bowling alley instead of a bowling ball If the two balls have the same speed, the volleyball will knock down fewer pins than the bowling ball Even though the balls have the same speed, the volleyball has less kinetic energy because it has less mass Figure shows how the kinetic energy of moving objects depends on their mass and speed The two cars have the same mass, but they don’t have the same kinetic energy The blue car has more kinetic energy because it is moving faster The truck and the blue car have the same speed However, the truck has more kinetic energy because its mass is greater Units of Energy Energy is measured in units of joules, abbreviated as J If you dropped a softball from a height of about 0.5 m, it would have about J of kinetic energy before it hit the floor All forms of energy are measured in units of joules Figure The kinetic energy of each vehicle depends on its mass and speed The truck has more kinetic energy than the blue car because it has more mass The blue car has more kinetic energy than the green car because it is moving faster Compare the kinetic energy of the two cars if they have the same speed BVhh2&%!%%%`\ HeZZY2 '%b$h HeZZY2 &*b$h BVhh2&!*%%`\ HeZZY2 '%b$h BVhh2&!*%%`\ GdX`]VhbdgZ ediZci^VaZcZg\n# GdX`]VhaZhh ediZci^VaZcZg\n# How deep is the crater? Procedure The rock has potential energy because it is above the ground The potential energy of the rock changed the car Figure An object can have potential energy that causes a change to occur Potential Energy—Stored Energy An object can have energy even if it is not moving Look at the hanging rock in Figure Would you say it has energy? Even though no changes are occurring, the rock still has energy Remember that energy is the ability to cause change When the rock falls, it causes a change Because the rock had the ability to cause change before it fell, it had energy as it was hanging above the car The hanging rock has stored energy, called potential (puh TEN chul) energy There are different forms of potential energy Gravitational Potential Energy The rock hanging above the ground has a form of stored energy called gravitational potential energy This form of energy is due to the downward pull of Earth’s gravity Gravitational potential energy depends on an object’s mass and its height above the ground The hanging rock in Figure has gravitational potential energy due to its height above the ground The higher an object is above the ground or the greater its mass, the more gravitational potential energy it has For example, the hanging rock in Figure would cause even more damage if it fell from a greater height More damage also would be caused if a rock with more mass fell from the same height The gravitational potential energy of an object increases if its mass or height above the ground increases Complete a lab safety form Smooth out modeling clay on the floor to a depth of a few inches Measure the mass of a marble Drop the marble onto the clay from a height of 1.5 m Measure the depth of the crater Repeat with a golf ball Analysis Relate the depth of the crater to the mass of the balls Infer how the potential energy of the balls before they fell depended on their masses 3.a WORD ORIGIN potential from Latin potens, means power What are two ways to increase an object’s gravitational potential energy? Lesson • Forms of Energy 127 (l)Jenni Carter/Biennale of Sydney, (c)REUTERS/Will Burgess/Landov, (r)Matt Meadows :cZg\n^hhidgZY^ci]Zheg^c\ l]Zc^i^hXdbegZhhZY JcXdbegZhhZY heg^c\ JchigZiX]ZY heg^c\ GZhiaZc\i] Figure A spring has elastic potential energy when it is compressed or stretched :cZg\n^hhidgZY^ci]Zheg^c\ l]Zc^i^hhigZiX]ZY GZhiaZc\i] Elastic Potential Energy Identify two ways a spring can store elastic potential energy SCIENCE USE V COMMON USE matter Science Use something that has mass and occupies space The weight of an object depends on the amount of matter it contains Common Use trouble or difficulty What’s the matter with your CD player? If you stretch a rubber band and then let it go, you know about another type of stored energy Elastic (ih LAS tik) potential energy is the energy stored when an object is squeezed or stretched When you stretch a rubber band, the elastic potential energy of the rubber band increases This stored energy then can cause the rubber band to fly across the room when you let it go Figure shows the two ways that a spring can store elastic potential energy If the spring is squeezed together, or compressed, it has a tendency to change back to its rest length The spring also will return to its rest length if it is stretched Either by compression or stretching, stored elastic potential energy gives an object the ability to change Chemical Potential Energy When you eat, you take in another type of potential energy Chemical potential energy is the energy stored in bonds between the atoms that make up matter Remember that atoms are joined together by chemical bonds to form molecules, as shown in Figure Chemical potential energy can be released during chemical reactions when these bonds are broken and new bonds are formed You get energy by eating because food contains chemical potential energy Fossil fuels, such as oil and coal, are energy sources because they contain chemical potential energy Figure The atoms in molecules are held together by chemical bonds that store chemical potential energy :cZg\n^hhidgZY^c i]ZX]Zb^XVaWdcYh WZilZZcVidbh# 8]Zb^XVa WdcY Thermal energy moves from warmer to cooler materials until the materials have the same temperature Lesson Forms of Energy >ˆ˜Ê`i> Energy exists in many forms 3.a • • • Energy is the ability to cause change • Kinetic energy is energy of motion • • Potential energy is stored energy • • elastic potential energy (p 128) energy (p 124) kinetic energy (p 124) potential energy (p 127) thermal energy (p 129) ˆ} >ˆ˜ Thermal energy moves because of a temperature difference *ˆVÌÕÀi `i> ˆ} >ˆ˜ • *ˆVÌÕÀi `i> Lesson Energy Transfer ,i>`ˆ˜} >ˆ˜Ê`i> …iVŽ Energy can be transferred from one place to ,i>`ˆ˜} …iVŽ another • Moving objects transfer kinetic energy from place to place • Water waves and sound waves transfer energy through matter • Electromagnetic waves transfer energy through matter or empty space • Fuels store energy that can be changed into other forms of energy ˆ} >ˆ˜ *ˆVÌÕÀi `i> Lesson Temperature, Thermal Energy, and Heat ,i>`ˆ˜} …iVŽ >ˆ˜Ê`i> Thermal energy flows from areas of high temperature to areas of low temperature • Temperature is a measure of the average kinetic energy of the particles in matter • Materials usually expand if their temperature increases • 3.a, 3.b friction (p 136) fuel (p 135) • wave (p 132) • work (p 132) • • 3.a, 7.c heat (p 142) temperature (p 140) • thermal expansion (p 140) • • Download quizzes, key terms, and flash cards from ca6.msscience.com Heat is the flow of thermal energy from a higher to a lower temperature ˆ} >ˆ˜ *ˆVÌÕÀi `i> Lesson Conduction, Convection, and Radiation ,i>`ˆ˜} …iVŽ >ˆ˜Ê`i> Thermal energy is transferred by conduction, convection, and radiation • Conduction occurs when thermal energy is transferred by collisions between the particles in matter • Convection is the flow of thermal energy due to the movement of matter from one place to another 3.c, 3.d, 7.a • • • • • • conduction (p 145) conductor (p 146) convection (p 147) convection current (p 149) fluid (p 147) radiation (p 150) • >ˆ˜ Radiation `i> is ˆ} the transfer of thermal energy by electromagnetic waves *ˆVÌÕÀi ,i>`ˆ˜} …iVŽ 156 Chapter • Standards Study Guide Interactive Tutor ca6.msscience.com StandardsReview CHAPTER Linking Vocabulary and Main Ideas Use vocabulary terms from page 156 to complete this concept map has many forms depends on stored as mass transferred by speed gravitational potential energy chemical potential energy stored when objects are stretched collisions between particles electromagnetic waves squeezed movement of matter Visit ca6.msscience.com for: ▶ ▶ ▶ Vocabulary PuzzleMaker Vocabulary eFlashcards Multilingual Glossary Using Vocabulary Match a vocabulary term to each definition below an increase in the size of a substance when the temperature is increased 10 energy that can move from one place to another because of differences in temperature 11 energy of motion 12 transfer of energy from warmer to cooler matter 14 stored energy 15 transfer of thermal energy by collisions between particles in matter 16 a material in which thermal energy moves easily 17 thermal energy transfer by the movement of matter from one place to another 13 measure of the average kinetic energy of the particles in a material Chapter • Standards Review 157 CHAPTER Standards Review Understanding Main Ideas Milk at 19°C is mixed with hot chocolate at 55°C What could be the temperature of the mixture? A 17°C 3.a B 42°C C 59°C D 74°C Choose the word or phrase that best answers the question Which is an example of chemical potential energy changing to kinetic energy? A a flag flapping in the wind B logs burning on a fire C using a battery in a flashlight D burning fuel to move a car 3.b The photo below shows a boy pushing on a wall Which of the following can cause a convection current? A heating a liquid from above 3.c B heating a liquid from below C cooling a solid from above D cooling a solid from below The kinetic energy of an object depends on which? A the object’s chemical bonds 3.a B the object’s mass and speed C the object’s temperature and mass D height of the object above the ground The table below shows some conductors and insulators Conductors and Insulators Why is no work being done by the boy? A The boy is not pushing hard enough 3.b B The wall is pushing back on the student C There is no motion in the direction of the force D The gravitational potential energy of the wall is not changing You place a pan on a hot stove Which is true? A The random motion of the water particles decreases B The average kinetic energy of the water particles increases C The water particles are closer together and are better able to transfer energy D The volume of the water increases as the water particle speed decreases 3.c 158 Chapter • Standards Review Matt Meadows Conductors Insulators Silver Air Copper Plastic foam Aluminum Fiberglass Through which material does thermal energy flow the slowest? A Aluminum B Copper C Fiberglass D Silver 3.c What happens to aluminum if you increase its temperature? A volume increases, density increases B volume increases, density decreases C volume decreases, density increases D volume decreases, density decreases 3.c Standards Review ca6.msscience.com Standards Review Applying Science CHAPTER Cumulative Review Explain the energy transformations and transfers that occur when a candle is used to heat a beaker of water 3.b 19 Explain how Earth’s temperature changes with depth, if thermal energy flows from Earth’s core to Earth’s surface 1.b, 3.a 10 Infer why you can keep cooler on a sunny day if you sit under a tree or umbrella 3.d 20 Diagram how a convection current transfers thermal energy within Earth’s mantle 1.b, 3.c 11 The figure below shows sound waves produced by a drum 21 Determine the method of heat transfer that occurs in Earth’s solid inner core 1.b, 3.c Applying Math Describe how energy is transferred by sound waves 3.a 12 Design an experiment to test which colors of fabric are the most efficient absorbers of radiation Design the experiment to test the fabrics by placing them in direct sunlight for a period of time 3.d 13 Describe three methods of thermal energy transfer 3.c 14 Explain how a hot cup of tea and a cold glass of lemonade reach room temperature when both are placed on a kitchen table In which direction does thermal energy flow in each case? 3.a 15 Describe how the potential energy and the kinetic energy of a ball change as the ball falls 3.a 16 Explain why materials that contain many small pockets of air are good insulators 3.c 17 Explain whether your body gains or loses thermal energy if your body temperature is 37°C and the temperature of the air surrounding your body is 25°C 3.a 3CIENCE 18 Write a paragraph that describes the relationship between thermal energy, temperature, ELA6: W 1.2 and heat Use the table below to answer questions 22 through 26 Linear Thermal Expansion Coefficients Material Linear Thermal Expansion Coefficient (ppm/°C) Aluminum 23 Brass 20 Diamond Steel 12 22 Find the volumetric thermal expansion coefficient for brass MA6: NS 2.0 23 Find the difference in the volumetric thermal expansion coefficient for brass and the volumetric thermal expansion coefficient of aluminum MA6: NS 2.0 24 Find the volumetric thermal expansion coefficient for steel MA6: NS 2.0 25 Find the difference in the volumetric thermal expansion coefficient for brass and the volumetric thermal expansion coefficient of steel MA6: NS 2.0 26 Find the volumetric thermal expansion coefficient for diamond MA6: NS 2.0 Chapter • Standards Review 159 Wolfgang Kaehler CHAPTER Standards Assessment Which is a true statement? A Waves can transfer energy through matter and empty space 3.a The illustration below shows a the movement of air in a room heated by a furnace B Waves can transfer energy through matter, but not through empty space H G C Waves can transfer energy through liquids and solids, but not through gases or empty space D Waves can transfer matter, but not energy The illustration below shows an ice cube in a glass of room-temperature water Air duct Exhaust Furnace Fan How does the air at point G compare to the air at point H? A The air at point G is warmer and denser 3.c B The air at point G is warmer and less dense C The air at point G is cooler and denser Which occurred when the ice was added to the water? D The air at point G is cooler and less dense A The temperature of the water increased How does thermal energy move as a you hold an ice cube in your hand? B The temperature of the ice decreased A by convection from the ice to your hand C Thermal energy moved from the ice to the water B by convection from your hand to the ice D Thermal energy moved from the water to the ice 3.a C by conduction from your hand to the ice D by conduction from the ice to your hand 3.c The transfer of thermal energy from the Sun to Earth is an example of which process? A conduction B convection C radiation D thermal expansion 160 Chapter • Standards Assessment 3.d Standards Assessment ca6.msscience.com Standards Assessment What must happen for work to be done? CHAPTER The illustration below shows a wave on a rope A An object must speed up F B A force must be exerted on an object J C The direction in which an object is moving must change G D A force must move an object in the same direction as the force 3.b Which is a the best conductor of thermal energy? Which property of the wave is shown at J? A copper A amplitude B rubber B frequency C wood C trough D air 3.c The illustration below shows the movement of air near a shoreline D wavelength 3.a 10 Which process causes thermal energy to move through a metal spoon placed in a pot of boiling water? A conduction LVgbV^g B convection C radiation D insulation 3.c 11 As a pan of water is heated, how does the motion of the water molecules change? 8ddaV^g A They move slower B They move faster Which best describes this process? C Their speed doesn’t change and they move farther apart A contraction D Their speed doesn’t change and they move closer together 3.c B expansion C conduction D convection 3.c Chapter • Standards Assessment 161 ... Lesson • Conduction, Convection, and Radiation 145 Theo Allofs/zefa/CORBIS Conduction in Solids Is metal a good conductor? Safety Precautions Conduction transfers thermal energy by collisions... becomes hot Figure 22 Thermal energy moves by conduction throughout the pot Vocabulary conduction conductor convection fluid convection current radiation I]ZgbVa ZcZg Review Vocabulary density:... energy is transferred by conduction, convection, and radiation Real-Life Reading Connection When it is cold outside, you might put on a coat or sweatshirt Why does putting on another layer of clothes