Heat Transfer
What process causes the air to circulate in the atmosphere?
The ground is heated by the Sun and then heats the air, causing the air to rise.
What is the original source of most of the energy people use?
Energy that reaches Earth's surfacce by radiation from the Sun.
What happens to the density of water as the temperature increases?
The density decreases.
What causes the tectonic plates of Earth to move?
Convection currents in the mantle.
A solar cooker uses sunlight to heat food. When is this product most effective?
When electricity is unavailable.
Why does a person standing in front of a fire feel warm?
Radiation and convection
Why are electrical wires coated with rubber or plastic?
These materials are good insulators.
What is the temperature of water just after an ice cube at 00 C melts in a glass of water at 280 C?
Between 00 C and 280 C
What process explains how heat from the core reaches Earth's surface?
Hot materials in the mantle circulate the same way warm air rises and cool air sinks in a heated room.
What kind of circuit should John build to light two light bulbs at the same time using one battery?
A parallel circuit
What condition is necessary for heat conduction to occur?
Two objects at different temperatures must be touching.
Which material would be best for reducing the transfer of thermal energy in insulated containers?
Crumpled paper
How does energy transfer from the Sun to Earth compare to how energy is distributed in ocean water?
Energy from the Sun is tranferred through radiation, while energy in ocean water is tranferred by convection.
How does the way heat moves in a room warmed by a heater compare to how heat moves from the Earth's core to the surface?
Both systems use convection currents to transfer heat.
What does an experiment with a balloon placed in a freezer demonstrate?
Cooling causes air to contract, and heating causes air to expand.
Why is all the water in a beaker the same temperature, even though heat is applied only at the bottom?
Heated water molecules and steam rise, carrying heat by convection.
Which substance would make the best insulator against the flow of electricity?
Plastic or rubber
Which material is a better insulator based on an experiment measuring temperature change in beakers wrapped in different materials?
- paper, cloth, metal foil, or plastic film
Cloth is a better insulator than metal foil.
What process causes your skin to feel warm when in the sun on a summer day?
The sun radiates energy that passes through space and the atmosphere to your skin.
What best describes the way heat transfers in a room when a heater is on?
Convection currents move warm air upward and cooler air downward.
What process causes an ice cube to melt on a sidewalk on a warm day?
Heat transferred from the air and pavement by conduction.
What best describes the tranformation of chemical energy in a battery when a wire is connected, making a nail attract metal objects?
Electrical energy is tranformed into magnetic energy.
Why do plastic materials often cover metal objects?
Plastic is a poor conductor of thermal energy and electricity.
What happens to air when it is cooled versus when it is heated?
Cooling causes air to contract, heating causes air to expand.
What materials should be used in an insulated container to slow heat tranfer?
Crumpled paper or air pockets.