Energy: Conservation and Transfer

Which material is the best conductor of electricity?

• wood
• metal
• stone
• plastic

When you are riding a bicycle at night, your bicycle's reflectors help people in cars see your bicycle. How do bicycle reflectors work?

• They are made of a special material that gives off its own light.
• They are hooked up to batteries that allow them to produce light.
• They bounce light back from other sources.
• They are covered with paint that glows in the dark.

A thermometer shows that the outside air temperature is colder than the temperature at
which water turns to ice. However, ice on the sidewalk melts. What probably caused this?

• The air heating the sidewalk
• The sidewalk reflecting sunlight into the air
• The wind causing the ice on the sidewalk to melt
• The sunlight making the sidewalk warmer than the air

Which statement explains why light from the Sun can warm up water in a glass?

• Light travels very fast.
• Light travels in straight lines.
• Water reflects light energy.
• Water absorbs light energy.

Thermal energy is transferred through a material by the collision of _______ within the
material.

• matter
• atoms
• crystals
• light

Which of the following waves is not visible to the human eye?

• Red light
• Violet light
• Ultraviolet light
• Blue light

The change in the direction of a wave when it enters a new medium is called________.

• Diffraction
• Reflection
• Refraction
• Superposition

What kind of energy does a moving baseball have?

• Electrical
• Magnetic
• Mechanical
• Chemical

Which kind of energy is produced by generators at a dam?

• Nuclear
• Electrical
• Chemical
• Solar

Which of the following materials is the best insulator?

• Copper
• Nickel
• Gold
• Wood