Energy: Conservation and Transfer

Which material is the best conductor of electricity?  

• Wood 
• Metal 
• Stone 
• Plastic

Energy is transferred from the sun to Earth mainly by _______________. 

• Sound Waves
• Air Currents
• Electromagnetic Waves
• Compressional Waves

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. 

in general, metals are _____________________________.  

•  poor conductors of heat
  
•  brittle
  
• poor conductors of electricity 
•  good conductors of heat 

When you hold an ice cube, your hand feels cold because  

• the cold flows from the ice cube to your hand.
  
•  heat flows from your hand to the ice cube.
  
• ce is a poor conductor of heat. 
• your hand is a better conductor of heat than the ice cube. 

The main method of heat transfer occurring within water is called __________. 

• conduction 
• convection 
• radiation 
• insulation 

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