Unit 1 Review-8th grade

Rafael broke a small twig off a tree and threw it in the lake. It floated away. If he could somehow push the whole tree into the lake and it floated, which of the following would explain why it floats?

• The temperature of the tree is less than the temperature of the water.

• The volume of the tree is less than the volume of the water.

• The mass of the tree is less than the mass of the water.

• The density of the tree is less than the density of the water.

Ryan boiled a liter of water and then stirred sugar into it, adding more sugar until no more would dissolve in the water, creating a saturated solution. If he pours more sugar into it after it has had a chance to cool, what will most likely happen?

• All of the sugar will come out of solution, and pure water will float to the top.

• If he stirs constantly, the sugar will form into one large sugar crystal.

• The added sugar will sink to the bottom.

• The added sugar will dissolve in the water.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4

Sarah is completing a lab in which she is required to identify an unknown substance. She records several observations and measurements of the substance. Which of the following properties will be most helpful to Sarah in making a correct identification?

• Density

• Mass

• Volume

• Weight

Katie's teacher has given her a sample that contains a mixture of salt, sand, and iron filings. She is instructed to separate the mixture into the three individual components. What would be the best physical property to focus on for the first step in separating the mixture?

• Density

• Electrical conductivity

• Magnetism

• Melting point

Julie has an unknown substance in a beaker. Its properties are described in the chart below. (D= M/V)

Use the information in the chart to identify which substance Julie has in the beaker.

• Iron

• Water

• Nitrogen

• Sulphur

Alexis predicts that the size of a magnet affects its magnetic properties. She designs an experiment using magnets of different sizes and paperclips to test her prediction. She takes three magnets of different sizes (one small, one medium, and one large) and holds them over a container of paperclips to see how many are attracted. Her results are shown in the table.

What should Alexis do next after examining her experimental results?

• Alexis should change her hypothesis to match the data she collected.

• Alexis should ask a friend to look for a pattern in the data she collected.

• Alexis should write a conclusion that confirms larger magnets have greater magnetic properties.

• Alexis should conduct more trials to see if there is a correlation between magnet size and magnetic properties.

What subatomic particle(s) are found in the atom's nucleus?

• Protons

• Neutrons

• Electrons

• Both Protons and Neutrons

Tags

NGSS.MS-PS1-1

Amy's science teacher shows her class a model of an atom. Why is a model useful for studying atoms?

• All atoms exist in the gas phase, and atmospheric gases are invisible.

• A model is helpful to observe the behavior of the parts of an atom.

• The parts of an atom cannot be directly observed.

• A model of an atom is the same for all atoms.

Tags

NGSS.MS-PS1-1

Sarah is completing a lab in which she is required to identify an unknown substance. She records several observations and measurements of the substance. Which of the following properties will be most helpful to Sarah in making a correct identification?

• Density

• Mass

• Volume

• Weight

Tags

NGSS.MS-PS3-4

A rock was dropped into water in a graduated cylinder. What is the correct volume of the rock?

• 25 ML

• 40 ML

• 65 ML

• 105 ML

Tags

NGSS.MS-PS1-2