Two wires carrying electricity can create a spark if they come too close together. This spark can start a fire. Wires carrying electricity are usuallly covered  with plastic to keep them from starting a fire. Why does the plastic keep electricity from starting a fire?

• Plastic is a good insulator.
• Plastic can melt when heated.
• Plastic is softer than wire.
• Plastic conducts electricity.

Tags

CCSS.RI.3.3

CCSS.RI.4.3

CCSS.RI.5.3

CCSS.RI.6.3

CCSS.RI.7.3

Erosion is one of the processes involved in the formation of sedimentary rock. Which of these best describes the process of erosion?

• Rocks are broken into smaller pieces that remain in the same location.
• Pressure compacts layers of sediment and turns them into rock.
• Pieces of rock or soil are carried from one place to another.
• Sediment grains fall to the bottom of a lake to form sedimentary layers.

A student observing birds in a park records some ways that birds interact with living and nonliving parts of their environment. All the following  observations are was that a bird interacts with nonliving parts of its environment except______

• reacting to morning sunlight by singing
• drinking and taking a bath in a puddle of water
• responding to cold temperatures by fluffing its feathers
• feeding insects to its chicks

A student made a list of activities that involve energy.  
-
1. Sharks chasing a school of fish
2. A toaster heating bread
3. A cell phone charging
4. A tree limb falling to the ground
5. Tomato plants absorbing sunlight
6. A canoe floating down a river
-
Which activities on the list are examples of the use of mechanical energy? 

• Activities 1, 4, and 6 
• Activities 2, 4, and 5
• Activities 1 and 2 
• Activities 3, 5, and 6 

A student combined powdered paint with water to make a small amount of a blue liquid paint mixture. The student left the paint mixture in an open container. Several days later the student found the container and observed that changes had occurred. What most likely happened to the mixture?

• The container was empty after the mixture evaporated into the air.  
• The paint evaporated, leaving only clear water in the container.
• The water evaporated, leaving only a dry blue solid in the container.  
• The liquid paint mixture was lighter in color after some water evaporated.  

Tropical climates have warm temperatures and abundant sunlight all year. What must be available for plants in these climates to make their own food throughout the year?

• Bacteria 
• Birds  
• Shade
• Water

Tags

CCSS.RI.5.2

CCSS.RI.6.2

CCSS.RL.5.1

CCSS.RL.5.2

CCSS.RL.6.2

A student puts four objects in a bucket filled with water. The objects are listed below. 
-
 Plastic ball
Glass marble
Metal paper clip
Wood block 
-
Which two objects are most likely less dense than the water?

• Wood block and metal paper clip
• Plastic ball and glass marble
• Metal paper clip and glass marble
• Wood block and plastic ball

Most alternative energy resources produce more energy at certain times. Which combination can produce a steady flow of energy from only alternative resources 24 hours a day year-round? 

• Geothermal and natural gas
• Hydroelectric and geothermal 
• Solar and petroleum 
• Wind and coal 

What would most likely happen to the carbon dioxide–oxygen cycle if Earth’s large forests were all cut down?

•  There would be more carbon dioxide in the atmosphere because fewer plants would be using it to produce their own food.
• The remaining plants would stop producing carbon dioxide, and animals would use less oxygen.
• The remaining plants would produce more oxygen, and animals would produce less carbon dioxide.
• There would be more oxygen in the atmosphere because fewer plants would be using it to produce their own food.

Which of these is not soluble in water?

• Oil
• Salt
• Honey
• Sugar