Olin and Katherine build an electromagnet by wrapping a wire around a nail and connecting the wire to both terminals of a battery. When they test the electromagnet, it can pick up 6 paper clips. Their teacher wants all groups to pick up at least 10 paper clips. What revisions could Olin and Katherine make to increase the number of paper clips their electromagnet picks up?

• make the wire longer

• remove the nail from the center of the wire

• increase the number of loops of wire around the nail

• spread the loops of wire apart on the nail so they do not touch

Tags

NGSS.MS-ETS1-1

NGSS.MS-ETS1-2

NGSS.MS-PS2-5

There is a single path for electrons. The current decreases when additional resistors are added. The current will be the same in each resistor. These statements BEST describe a(n) _____________ circuit.

• closed

• open

• parallel

• series

Chemical cells wired in series make the battery last ____________ those in parallel. Given both circuits receive the same load over the same time period.

• longer than

• shorter than

• the same as

• less efficiently than

Which is a source of direct current (DC)?

• generator

• wall socket

• electromagnetic induction

• chemical cells or batteries

Why might an electromagnet be used to pick up heavy scrap metal in junk yards?

• Electromagnets are inexpensive and easily create revenue.

• Electromagnets are powerful and can be turned on and off easily.

• Electromagnets are easy to operate and can be run by cheap labor.

• Electromagnets are versatile and can pick up any metallic objects in the yard.

Tags

NGSS.MS-ETS1-1

NGSS.MS-PS2-5

Which is an example of gaining a static charge by conduction?

• Rubbing a balloon against your hair.

• Shuffling your shoes across a carpet.

• Placing a charged rod near a neutral object.

• Touching a metal pole and getting a shock.

One advantage to using this form of circuit is that

• voltage available to each light remains constant regardless of the number of lights that are on.

• current drawn from the battery remains constant regardless of the number of lights that are on.

• resistance along the circuit remains constant regardless of the number of lights that are on.

• current drawn from the battery decreases as more lights are turned on.

During induction, a positively charged rod is brought near to but not touching the electroscope. What happens to the electroscope?

• The electroscope becomes negatively charged.

• The electroscope remains neutral.

• The electroscope becomes positively charged.

• The electroscope discharges completely.

An electrician is creating a wiring plan for a small house. He needs to create a plan that will allow the homeowners to turn off lights in one room without turning off the lights in another. What should he do to assure that each room's lights function independently of one another?

• He should wire each room in series with the next.

• He should wire each room in parallel with the next.

• He should make sure each room's lights provide the same resistance.

• He should wire the room with the most lights directly to the circuit breaker box.

In a classroom experiment, a student rubs a brush against her hair. The brush is then brought near bits of paper resting on a surface. Which of these can be concluded if the brush picks up the bits of paper?

• The brush is an insulator, but paper conducts electricity.

• The brush had a net charge on it, and it attracted a neutral object.

• The brush was left uncharged, and it attracted a positively charged object.

• The brush was positively charged, and it attracted a negatively charged object.

Tags

NGSS.MS-PS2-3

NGSS.MS-PS2-5