Physical Science

Which of the following is evidence that an electrical current produces a magnetic field?

• Iron filings reveal magnetic field lines around an electrical wire.
• A magnet moved through a coil of electrical wire produces a current.
• Electrical wires have a positive (+) and negative (-) poles just as a bar magnet does.
• The magnetic field lines run east and west in a bar magnet, but they run north and south in a coil of wire. 

How does the mass of a jigsaw puzzle compare when the pieces are together or separated?

• The mass is greater when the pieces are together.
• The mass is greater when the pieces are separated.
• The mass is the same whether the pieces are together or separated.
• The mass of each piece is proportional to the total, so the mass of the complete puzzle can be calculated.

Which of the following is NOT a physical change that happens when water changes state?

• water boils
• water freezes
• ice sinks
• ice melts

What kind of change occurs when gaseous nitrogen becomes very cold and changes to a liquid?

• physical 
• chemical
• both chemical and physical
• neither chemical not physical 

Of these categories of materials, which would NOT make a good insulator?

• plastics
• metals
• rubber tubing
• cotton cloth

Which of the following demonstrates static electricity?

• You know you should never put your fingers into an electrical outlet.  You could get shocked.
• You bend a paper clip back and forth until it breaks.  The broken ends feel hot.
• You brush your hair on a cold, dry day.   Your hair springs away from your head in all different directions.
• You use a charger to charge batteries for a digital camera.

A scientist burns a known mass of liquid fuel with a known mass of oxygen inside a sealed container.  The liquid fuel disappears, but the mass of the container does not change.  Which of the following BEST explains the result?

• A chemical change formed products of less mass.
• A chemical reaction formed gaseous products.
• A physical change vaporized the fuel.
• A physical change turned the fuel and the oxygen into a new compound.

You weigh 1 ounce of cheese on a kitchen scale.  You grate the cheese and put it on your salad.  Predict the weight of the cheese after grating, assuming you don't leave any on your knife, grater, or cutting board.

• The weight of the grated cheese will be 1 ounce.
• The weight of the grated cheese will be greater than 1 ounce.
• The weight of the grated cheese will be less than 1 ounce.
• The weight of the grated cheese cannot be predicted, because a physical change has occured.

Water is a compound H20.  What are its smallest parts in water vapor?

• molecules of H20
• atoms of H and atoms of O
• drops of liquid water, H20
• charged elements of hydrogen and oxygen

What would you expect to find inside an electromagnet?

• a permanent magnet
• a coil of wire
• two bar magnets
• a device that uses electricity