S2 Ch10 (H)

• What does a change in temperature indicate?

  A change in temperature indicates a transfer of thermal energy.
• What effects does the transfer of heat energy have on an object?

  It can cause the object to expand or contract.
• How does the transfer of heat energy occur?

  Heat energy transfers from a region of higher temperature to a region of lower temperature.
• What affects the rate at which heat energy is transferred?

  The rate is affected by the temperature difference and the properties of the materials involved.
• What is the SI unit of temperature?

  Kelvin (K)
• How is temperature different from thermal energy?

  Temperature measures how hot or cold an object is, while thermal energy is the energy stored in the body due to its temperature.
• What happens to your hand when placed in Basin P (4°C)?

  Your hand feels cold because heat flows from your hand to the water.
• What happens to your hand when placed in Basin R (70°C)?

  Your hand feels hot because heat flows from the water to your hand.
• What occurs in Basin Q (37°C) regarding thermal energy transfer?

  There is no net gain or loss of thermal energy between the water and your hands.
• What is the net thermal energy transfer direction?

  Net thermal energy always flows from a region of higher temperature to a region of lower temperature.
• What happens when two bodies in thermal contact are in thermal equilibrium?

  There is no net transfer of thermal energy between them.
• What happens to a substance when it is heated?

  It increases in size, a process known as expansion.
• What happens to a substance when it is cooled?

  It decreases in size, a process known as contraction.
• How do solids generally behave when heated and cooled?

  Solids usually expand when heated and contract when cooled.
• What is the purpose of the mercury in a thermometer?

  It demonstrates the concept of expansion and contraction.
• What happens to a steel rod when it is heated and then allowed to cool?

  It may break if it is fixed in position while cooling.
• What happens to water when it is heated in a pot or kettle?

  It expands and may spill out if filled to the brim.
• What is observed when a glass flask containing colored water is placed in hot water?

  The liquid level rises, indicating expansion of the colored water.
• What happens when the flask with colored water is placed in ice water?

  The liquid level drops, indicating contraction of the colored water.
• How do gases behave when heated and cooled?

  Gases expand when heated and contract when cooled.
• What happens to air in a heated flask?

  The air expands and pushes a drop of colored water upwards in the tube.
• What solutions are introduced to accommodate expansion in bridges and metal girders?

  Expansion gaps or free ends resting on rollers are used.
• How do telephone wires behave in cold weather?

  They contract and may snap if strung too tightly.
• What is a bimetallic strip?

  It is made of two different metals that expand at different rates when heated.
• What happens to a bimetallic strip when heated?

  The strip bends with the metal that expands more on the outside of the curve.
• What happens to a bimetallic strip when cooled?

  The strip bends with the metal that contracts more on the outside of the curve.
• How does a bimetallic thermometer work?

  It tightens or unwinds as temperature changes, moving a pointer over a scale marked in temperature degrees.
• What happens to the pointer in a bimetallic thermometer as temperature increases?

  The pointer moves over the scale as the coil tightens.
• What are the effects of heat on different states of matter?

  • Solids: Expand when heated, contract when cooled.
  • Liquids: Expand when heated, contract when cooled.
  • Gases: Expand when heated, contract when cooled.
• What are the uses of bimetallic strips?

  • Thermostats for temperature control.
  • Bimetallic thermometers for measuring temperature.
• What is a bimetallic strip used for in a thermostat?

  To keep temperature constant
• How does a bimetallic strip function in an oven?

  It bends away to break contact when the temperature is too hot
• How does a bimetallic strip function in a refrigerator?

  It bends away to break contact when the temperature is too cold
• What is conduction?

  Conduction is the transfer of thermal energy through a medium without any flow of the medium
• How does conduction work at the molecular level?

  Particles at the heated end vibrate and collide with neighboring particles, transferring energy
• Why do metals conduct thermal energy more quickly than non-metals?

  Metals have free electrons that facilitate faster energy transfer
• What is the difference between thermal energy transfer in metals and non-metals?

  In metals, thermal energy is transferred through free electron diffusion, while in non-metals it is through particle vibration
• What is the effect of heating water in a flask?

  The heated water expands and becomes less dense, causing it to rise
• How do convection currents form in liquids?

  Convection currents form due to differences in density caused by temperature changes
• How do land and sea breezes occur?

  Land heats up faster than the sea during the day, causing air to rise and creating a sea breeze