In an investigation hot water is poured into a clear plastic cup. Another clear plastic cup is placed upside down over the cup of hot water.

Which of these is likely to occur (happen) during the next three minutes?

• The hot water will become hotter because air and heat are trapped in the cup.

• The water level will rise in the bottom cup because of evaporation.

• Water droplets will form on the inside of the top cup as the water vapor cools.

• Water from the bottom cup will become solid as the hot water cools.

Answer explanation

The water was warm, so water vapor will be floating in the upper area. As the cups sit there, things are going to cool off. When water vapor (gas) cools, it condenses and changes into liquid water droplets.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

NGSS.MS-PS3-5

A student observed liquid wax dripping down the side of a burning candle. After putting out the candle's flame, the student left the room. Several hours later the student observed that there was no longer any liquid wax on the side of the candle. Which statement explains what most likely happened to the liquid wax?

• The heat given off by the flame caused the candle wax to evaporate.

• The liquid wax changed back into a solid as it cooled.

• The liquid wax condensed and was absorbed by the candle.

• Nothing changed.

Answer explanation

As it sits there, the hot melted wax will begin to cool. When it cools off, it will change from a liquid into a solid.

Tags

NGSS.MS-PS1-4

A student makes a model of the water cycle by using a cup, some water, and some plastic wrap. After the student places the model near a sunny window, water droplets form on the underside of the plastic wrap.

How did the water droplets form?

• Freezing

• Condensation

• Melting

• Sublimation

Answer explanation

The sun made the liquid water turn into water vapor (gas). When the water vapor touches onto the plastic wrap, it changes from water vapor (gas) into liquid water droplets (condensation).

Tags

NGSS.MS-ESS2-1

NGSS.MS-ESS2-4

A student is asked to design a sleeve for a cup that will insulate thermal energy and not feel hot to the touch when the cup is filled with hot liquid.

The student has four materials to choose from. Which of these materials is LEAST useful as an insulator.

• Cardboard

• Aluminum

• Rubber

• Plastic

Answer explanation

Cardboard, rubber, and plastic all insulate against thermal energy. Aluminum is a conductor of thermal energy.

Tags

NGSS.MS-ETS1-1

NGSS.MS-ETS1-2

NGSS.MS-PS3-3

For an investigation a teacher dropped a bolt into a container of maple syrup and asked students to remove it without touching the syrup. The students first tried to use a strong magnet to removed the bolt, but it remained on the bottom of the container. They finally poured the syrup into another container and then reached in to get the bolt out.

Which of these best describes some of the bolt's physical properties?

• The bolt is magnetic and is more dense than the syrup.

• The bolt is nonmagnetic and is more dense than the syrup.

• The bolt is nonmagnetic and less dense than the syrup.

• The bolt is magnetic and less dense than the syrup.

Answer explanation

The magnet didn't pick up the bold, so the bolt is nonmagnetic. The bolt sank to the bottom of the container, so it is more dense than the maple syrup.

Tags

NGSS.MS-PS1-2

Two wires carrying electricity can create a spark if they come too close together. This spark can start a fire. Wires carrying electricity are usually 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 is a good conductor.

A student puts four objects in a bucket filled with water. The objects are listed below:

• Plastic ball

• Glass marble

• Metal paperclip

• Wood block

Which two objects are most likely less dense than the water?

• Plastic ball

• Glass marble

• Metal paperclip

• Wood block

Answer explanation

Less dense than water (will float): plastic ball, wood block

More dense than water (will sink): metal paperclip, glass marble

A student was asked to compare the masses of four blocks that were all the same size but made of different materials. The student used a balance to compare the masses of the blocks. The student repeated the process several times.

Which list shows the blocks IN ORDER from LEAST to GREATEST mass?

• Blocks N, M, L, P

• Blocks P, M, L, N

• Blocks N, L, M, P

• Blocks P, L, M, N

Answer explanation

Compare the blocks against each other.

Find block P.

P is lighter than M. P is also lighter than N.

Block P is the lightest one of all.

L is heavier than M. L is lighter than N.

N is heavier than L. N is not lighter than any of the other blocks. N is the heaviest one.

The table lists some properties of four different samples of matter.

Which two samples could be GLASS and SALTWATER?

• 1

• 2

• 3

• 4

Answer explanation

Glass is a solid. Glass is clear. Glass is not attracted to a magnet. Glass does not conduct electricity.

Saltwater is a liquid. Saltwater is clear. Saltwater is not attracted to a magnet. Saltwater DOES conduct electricity.

Which of these is not soluble in water?

• oil

• salt

• honey

• sugar