Design for Heat Transfer - Middle School Physical Science
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What device feature reduces convection by limiting fluid motion: lid/seal or metal handle?
What device feature reduces convection by limiting fluid motion: lid/seal or metal handle?
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Lid or seal. Prevents air currents from carrying heat away.
Lid or seal. Prevents air currents from carrying heat away.
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What is convection as a method of thermal energy transfer?
What is convection as a method of thermal energy transfer?
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Heat transfer by moving fluids (liquids or gases). Warmer fluid rises, cooler fluid sinks, creating circulation.
Heat transfer by moving fluids (liquids or gases). Warmer fluid rises, cooler fluid sinks, creating circulation.
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Which design feature reduces heat transfer by radiation in a thermos: reflective lining or dark lining?
Which design feature reduces heat transfer by radiation in a thermos: reflective lining or dark lining?
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Reflective lining. Shiny surfaces reflect infrared radiation away.
Reflective lining. Shiny surfaces reflect infrared radiation away.
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What is thermal equilibrium between two objects in contact?
What is thermal equilibrium between two objects in contact?
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They have the same temperature and no net heat flows. Equal temperatures mean no driving force for heat transfer.
They have the same temperature and no net heat flows. Equal temperatures mean no driving force for heat transfer.
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What is conduction as a method of thermal energy transfer?
What is conduction as a method of thermal energy transfer?
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Heat transfer by direct contact between particles. Particles vibrate and transfer energy to neighboring particles.
Heat transfer by direct contact between particles. Particles vibrate and transfer energy to neighboring particles.
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What is radiation as a method of thermal energy transfer?
What is radiation as a method of thermal energy transfer?
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Heat transfer by electromagnetic waves. No medium needed; energy travels as infrared waves.
Heat transfer by electromagnetic waves. No medium needed; energy travels as infrared waves.
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Which method of heat transfer can occur through empty space: conduction, convection, or radiation?
Which method of heat transfer can occur through empty space: conduction, convection, or radiation?
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Radiation. Only electromagnetic waves can travel through a vacuum.
Radiation. Only electromagnetic waves can travel through a vacuum.
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What is the direction of net heat transfer between two objects at different temperatures?
What is the direction of net heat transfer between two objects at different temperatures?
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From higher temperature to lower temperature. Heat flows naturally from hot to cold until equilibrium.
From higher temperature to lower temperature. Heat flows naturally from hot to cold until equilibrium.
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Which material type is best for a pot handle to reduce heat transfer to a hand: conductor or insulator?
Which material type is best for a pot handle to reduce heat transfer to a hand: conductor or insulator?
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Insulator. Poor heat conductors prevent burns from hot cookware.
Insulator. Poor heat conductors prevent burns from hot cookware.
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Which material type is best for the bottom of a cooking pan to heat food quickly: conductor or insulator?
Which material type is best for the bottom of a cooking pan to heat food quickly: conductor or insulator?
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Conductor. Good heat conductors transfer energy efficiently to food.
Conductor. Good heat conductors transfer energy efficiently to food.
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Identify the surface finish that reduces radiative heat transfer: shiny silver or matte black.
Identify the surface finish that reduces radiative heat transfer: shiny silver or matte black.
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Shiny silver. Reflective surfaces reflect rather than absorb radiation.
Shiny silver. Reflective surfaces reflect rather than absorb radiation.
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Identify the surface finish that increases absorption of radiant energy: shiny white or matte black.
Identify the surface finish that increases absorption of radiant energy: shiny white or matte black.
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Matte black. Dark surfaces absorb more electromagnetic radiation.
Matte black. Dark surfaces absorb more electromagnetic radiation.
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What device feature reduces heat loss by convection in a hot drink container?
What device feature reduces heat loss by convection in a hot drink container?
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A tight-fitting lid. Prevents warm air from escaping and cold air entering.
A tight-fitting lid. Prevents warm air from escaping and cold air entering.
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What is the main reason trapped air in foam is a good thermal insulator?
What is the main reason trapped air in foam is a good thermal insulator?
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Air has low thermal conductivity and limits convection. Still air prevents heat flow by both methods.
Air has low thermal conductivity and limits convection. Still air prevents heat flow by both methods.
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What is the term for a material property describing how well it conducts heat?
What is the term for a material property describing how well it conducts heat?
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Thermal conductivity. Measured in W/(m·K), indicates heat flow ability.
Thermal conductivity. Measured in W/(m·K), indicates heat flow ability.
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Which design change increases conduction through a solid: thicker wall or thinner wall?
Which design change increases conduction through a solid: thicker wall or thinner wall?
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Thinner wall. Less material means less resistance to heat flow.
Thinner wall. Less material means less resistance to heat flow.
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Which design change decreases conduction through a solid: larger area or smaller area?
Which design change decreases conduction through a solid: larger area or smaller area?
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Smaller area. Less cross-sectional area reduces heat flow path.
Smaller area. Less cross-sectional area reduces heat flow path.
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Which design increases convection cooling of electronics: adding a fan or sealing the case tightly?
Which design increases convection cooling of electronics: adding a fan or sealing the case tightly?
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Adding a fan. Fans force air movement, increasing convective heat removal.
Adding a fan. Fans force air movement, increasing convective heat removal.
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What property of a material indicates how well it conducts heat in device design?
What property of a material indicates how well it conducts heat in device design?
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Thermal conductivity. Measures how easily heat flows through a material.
Thermal conductivity. Measures how easily heat flows through a material.
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Which option reduces unwanted conduction through a handle: metal handle or plastic handle?
Which option reduces unwanted conduction through a handle: metal handle or plastic handle?
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Plastic handle. Plastic is a poor conductor, preventing heat from reaching hands.
Plastic handle. Plastic is a poor conductor, preventing heat from reaching hands.
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Which design reduces convection inside a window: double-pane sealed air space or single-pane glass?
Which design reduces convection inside a window: double-pane sealed air space or single-pane glass?
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Double-pane sealed air space. Sealed air can't circulate, eliminating convection currents.
Double-pane sealed air space. Sealed air can't circulate, eliminating convection currents.
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Which design best reduces heat transfer by all three methods in a container: vacuum flask or thin metal cup?
Which design best reduces heat transfer by all three methods in a container: vacuum flask or thin metal cup?
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Vacuum flask. Vacuum stops conduction/convection; reflective walls reduce radiation.
Vacuum flask. Vacuum stops conduction/convection; reflective walls reduce radiation.
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Which surface increases radiative heat absorption: matte black or polished white?
Which surface increases radiative heat absorption: matte black or polished white?
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Matte black. Dark, rough surfaces absorb radiation efficiently.
Matte black. Dark, rough surfaces absorb radiation efficiently.
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Which surface reduces radiative heat loss: shiny silver or matte black?
Which surface reduces radiative heat loss: shiny silver or matte black?
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Shiny silver. Shiny surfaces reflect radiation instead of absorbing/emitting it.
Shiny silver. Shiny surfaces reflect radiation instead of absorbing/emitting it.
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Which design change increases conduction from a hot plate to a pot: smooth contact or air gap?
Which design change increases conduction from a hot plate to a pot: smooth contact or air gap?
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Smooth contact. Direct contact eliminates air gaps that resist heat flow.
Smooth contact. Direct contact eliminates air gaps that resist heat flow.
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