REVIEW FOR HEAT AND TEMPERATURE UNIT

1. REVIEW FOR HEAT AND TEMPERATURE UNIT SCIENCE 7 GCMS

2. PART ONE—MEASURING TEMPERATURE • Which of the following are typical ways that we can estimate the temperature of an item (how hot or cold it is)? • By touching the item • By the color of the light an item gives off (how much glow). • By the sound the item makes (popping of popcorn). • All the above are typical means of estimating temperature. • Only A and B are typical. • Answer is E

3. Question 2)Which of the following is the most reliable means of measuring temperature? • Looking at the color of the object. • Touching the object with your hand. • Using a thermometer to measure the temperature of the object. • Listening to the object. • Answer • C

4. Question 3)Which of the following measuring scales identifies “absolute zero” as 0o? • The Fahrenheit scale • The Centigrade scale • The Celsius scale • The Kelvin scale • Answer • D

5. Question 4)Which of the following statements describe how Anders Celsius designed his temperature scale? • He had to decide on an unit and standard for comparision. • He used the “degree” as the unit of temperature on his scale. • He based his standards for comparison on the properties of water (most abundant liquid on earth). • He assigned a value of 100 degrees to the temperature at which water boils at sea level. • He assigned a value of zero degrees for the temperature in which water freezes at sea level. • All the above are correct statements about how Anders Celsius designed his temperature scale. • Answer • F

6. Question 5)Which of the following statements are characteristics of a thermocouple? • A thermocouple can be used to measure very high temperatures that would cause the liquid to boil in a traditional thermometer. • A thermocouple can be used to accurately measure a very cold temperature. • A thermocouple is made of wires (each a different metal) twisted together. • When the twisted wire tips are heated, a small electrical current is generated. • The temperature determines the amount of electrical current generated. • Thermocouples are used to turn a switch or valve on or off if the temperature changes (pilot light for a gas furnace). • Answer • All but B are correct.

7. Question 6)Which of the following statements are characteristics of a bimetallic strip? • A bimetallic strip is made of two different metals joined firmly together. • When the strip is heated, one of the metals expands more than the other causing the strip to coil more tightly. • When the strip is cooled, the same metal that expanded rapidly will now contract rapidly causing the strip to uncoil. • Bimetallic strips can only be used in temperatures less than 100o C. • Bimetallic strips are often used to control furnaces, air conditioners and refrigerators. • Answer • All but D are correct.

8. Question 7)Which of the following statements are characteristics of a recording thermometer? • Recording thermometers are sometimes called thermographs. • A special pen can record the changes in temperature measured by a bimetallic strip. • The pen marks are recorded on paper attached to a slow moving drum that can measure changes for a week. • The recording thermometer requires constant monitoring by the user to record change in temperature. • Answer • All but D are correct.

9. Question 8)Which of the following statements are characteristics of a infrared thermogram or how it measures temperature? • Anything that is warmer than absolute zero gives off infrared radiation (IR) • Infrared radiation can be photographed with special film. • Infrared radiation can be detected by electronic sensors that display images on LCD screens. • You can actually see infrared radiation with your own eyes (un-aided). • The color or the brightness of the infrared image shows the temperature of the object. • Infrared Thermograms can be used to measure extremely hot surfaces. • Answer • All but D are correct.

10. Question 9)Which of the following are good thermal conductors, that is they are excellent at transferring heat? • Gold • Copper • Iron • Wood • All the above are excellent heat conductors. • Only A, B, and C are excellent heat conductors. • Answer • F

11. Question 10)Which of the following are poor thermal conductors, that is they are called heat insulators? • Neoprene Rubber • Steel • Plastic • Wood • All the above are poor heat conductors. • Only A, C, and D are poor heat conductors. • Answer • F

12. Question 11)Which of the following statements are typically true about radiation? • Radiation is the transfer of energy without any movement of matter. • Radiant energy (electromagnetic radiation—EMR) behaves like a wave. • Radiant energy can travel through empty space, air, glass and other transparent materials. • Examples of EMR waves used today include radio waves, microwaves, and X-rays. • EMR waves can be absorbed or reflected by objects. • EMR waves travel very slowly (slower than the speed of sound). • Answer • All but F are correct

13. Question 12)Which of the following statements are typically true about conduction? • Conduction is the transferring of thermal energy through direct collisions between particles. • Particles that are closest to the heat source absorb the energy and begin to move more rapidly. • Faster moving particles collide/bump into neighbouring particles increasing their energy and motion. • Conduction is consistent through all forms of matter (the thermal energy is transfer at the same rate, regardless of the material). • Poor heat conductors are called heat insulators (they slow down the transfer of thermal energy). • Answer • All but D are correct.

14. Question 13)Which of the following statements are typically true about convection? • Thermal energy can be transferred by fluids (materials that can be poured or that flow from place to place). • In convection, a warm fluid moves from place to place carrying the thermal energy with it. • Warm fluids tend to rise while colder fluids fall (this causes convection currents). • Convection can be explained by the fact that energy transfers from lower energy substances to higher energy substances. • Convection ovens use forced air to increase the heating capacity of your stove allowing you to cook food quicker than with a conventional oven. • Answer • All but D are correct.

15. Question 14)Which of the following statements are ideas that apply to the particle model of matter? • All substances are made of tiny particles too small to be seen. • The particles are always in motion—vibrating, rotating and moving from place to place (gases and liquids). • The particles have spaces between them. • The motion in the particles decreases when the temperature increases. • The motion in the particles decreases when the temperature decreases. • Answer • All but D are correct (increased temperature increases motion).

16. Answer True or False for Each of the following statements: • Materials in a solid state keep their shape and size. • True • Solids have a definite shape and volume but can be compressed into a smaller space. • False • Materials in a liquid state have a definite size (volume) but no fixed shape. • True • Liquids take the shape of their containers and can be compressed. • False • Gases have no definite shape or volume and can be easily compressed into a smaller space. • True • Contraction is the decrease in volume and occurs when objects cool. • True

17. Answer True or False for Each of the following statements: • Pressure can alter the boiling point and freezing temperature of water. • True • The lower the pressure the higher the boiling point temperature for water. • False • The higher the pressure the lower the melting point temperature for ice. • True • Impurities in water can change the boiling point and freezing point temperatures for water. • True

18. Answer True or False for Each of the following statements: • Absolute zero is approximately -273o Celsius. • True • Body temperature is approximately 37o Celsius. • True • Water freezes at 0o Celsius. • True • Water boils at 100o Celsius. • True • Energy can not be created or destroyed. It can only be transformed from one type to another or passed from one object to another. • True (law of conservation of energy)

19. Answer True or False for Each of the following statements: • Changes in energy only happen when there is a difference of energy (between to objects). • True • Energy is always transferred in the same direction. • True • Energy is always transferred from a high-energy source to a low-energy source. • True

20. Answer True or False to each statement about changes in state: • Changes in heat can cause changes in state (solid, liquid, gas or in the rare cases plasma). • True • During a phase change (solid to a liquid) the total energy of a substance does not change (increase or decrease). • False • During a phase change (liquid to a gas) the temperature of the substance does not increase it stays constant. • True • Although the particles do not increase or decrease in speed during a phase change the change in arrangement of the particles causes a total increase or decrease in energy to occur. • True

21. LINKS TO HEAT AND TEMPERATURE ANIMATIONS ON THE INTERNET • http://www.bbc.co.uk/schools/ks2bitesize/science/materials/ • http://www.worsleyschool.net/science/files/state/changes.html • FIRST FOUR ONLY AT SKOOOL SITE • http://lgfl.skoool.co.uk/keystage3.aspx?id=64 • http://www.usborne-quicklinks.com/ca/ca_entity_pages/ca_select_link.asp?lang=ca&lvl=2&menu=s100&id=1204&From=110&To=111 • (THE ABOVE LINK HAS MULTIPLE SITES AND A FEW IMAGES) • http://www.yteach.co.uk/index.php/resources/bromine_collision_ethanol_helium_sodium_tungsten_zinc_t_page_8.html