Unit 1–Forces Around Us Study Guide

A south pole will attract another magnet's ________ pole.

• north

• south

• east

• west

Answer explanation

A south pole of a magnet attracts the north pole of another magnet due to the fundamental magnetic principle that opposite poles attract. Therefore, the correct answer is 'north'.

A compass uses the ________ field of the Earth.

• Magnetic

• Electric

• Gravitational

• Thermal

Answer explanation

A compass operates based on the Earth's magnetic field, which allows it to align with the planet's magnetic poles. The other fields listed (electric, gravitational, thermal) do not influence compass functionality.

What type of electricity causes a shock when a person touches a doorknob?

• Static electricity

• Current electricity

• Solar electricity

• Magnetic electricity

Answer explanation

The shock from touching a doorknob is caused by static electricity, which builds up on surfaces and discharges when you touch a conductive object like a doorknob. Current electricity flows continuously, while static electricity is a sudden discharge.

What type of object may cause a static electricity shock?

• An metal or iron door knob (something metal)

• A wooden table

• A plastic cup

• A cotton shirt

Answer explanation

Metal objects, like an iron door knob, can easily conduct electricity and accumulate static charge, leading to a shock when touched. Other materials like wood, plastic, or cotton are less likely to cause static shocks.

Your papers keep falling off the refrigerator door. How could you solve this problem?

• You could get a stronger magnet

• You could use a paperclip

• You could tape the papers to the wall

• You could use a rubber band

Answer explanation

Getting a stronger magnet is the best solution because it will securely hold the papers on the refrigerator door, preventing them from falling off. Other options may not provide the same level of stability.

A magnet would attract paper clips and iron filings. Why?

• Because they are both magnetic

• Because they are both made of plastic

• Because they are both non-magnetic

• Because they are both liquids

Answer explanation

Paper clips and iron filings are both made of materials that are magnetic, allowing them to be attracted to a magnet. The other options are incorrect as they do not describe the properties of these materials.

What are some examples of how magnets can be used to solve a problem?

• A magnetic latch keeps a cabinet door closed. A person uses a magnet to attach a note to a refrigerator.

• A magnet is used to heat water. A magnet is used to cut paper.

• A magnet is used to grow plants. A magnet is used to cook food.

• A magnet is used to write on a chalkboard. A magnet is used to play music.

Answer explanation

The correct choice highlights practical uses of magnets: a magnetic latch secures a cabinet door, and a magnet can hold notes on a refrigerator, demonstrating how magnets can solve everyday problems effectively.

Name some objects that would be attracted to a magnet?

• An iron nail, a paperclip, car, scissors

• A wooden spoon, a plastic cup, a rubber band, a glass bottle

• A cotton shirt, a woolen scarf, a leather belt, a silk tie

• A ceramic mug, a paper towel, a plastic straw, a glass jar

Answer explanation

The correct choice includes objects made of ferromagnetic materials like iron, which are attracted to magnets. An iron nail and a paperclip are common examples, while scissors may also contain metal parts that are magnetic.

What type of magnetic charges attract each other?

• Positive attracts negative. Negative attracts positive. North attracts south. South attracts north. They must be opposite to attract.

• Positive attracts positive. North attracts north. South attracts south. Like charges attract.

• Negative attracts negative. North attracts north. South attracts south. Like poles attract.

• Positive attracts positive. Negative attracts negative. North attracts north. South attracts south.

Answer explanation

Magnetic charges follow the principle that opposite charges attract. Therefore, positive charges attract negative charges, and north poles attract south poles, confirming that they must be opposite to attract.

What is an example of static electricity in nature?

• Lightning

• Rainfall

• Wind blowing

• Photosynthesis

Answer explanation

Lightning is a natural example of static electricity, as it occurs when electrical charges build up in clouds and are discharged, creating a bright flash and thunder. The other options do not involve static electricity.