Grade 7 Unit 1 Science Test Review 2023-2024

What determines the direction of heat flow between two touching solid objects?

• the material of the objects.

• the volume of the objects.

• the density of the objects.

• the temperature of the objects.

John puts a cold soda can with a temperature of 20 ºC on a warm counter at 70 ºC. After a while, both are at the same temperature. What occurred?

• Both the soda can and the counter's temperature increased to 30 ºC.

• The soda can's temperature increases to 25 ºC, and the counter's temperature decreases to 25 ºC.

• The soda can's temperature stays the same, the counter's temperature decreases to 10 ºC.

• The counter's temperature stays the same, the soda can's temperature increases to 15 ºC.

Answer explanation

The direction of the flow of thermal energy (flow of heat) between two solid objects is determined by the temperature of the objects.

*Hot to cold until they are equal or balanced

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

You leave a small glass of water at 75 ºC in a large room with an air temperature of 25 ºC. You measure the temperature of the water every two minutes. At what temperature will the water in the glass stop cooling?

• 0 °C

• 25 °C

• 50 °C

• 80 °C

Answer explanation

The water temperature will stop decreasing when it's the same as the air temperature in the room.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

NGSS.MS-PS3-5

Changes of state occur when there is a change in?

• Thermal energy

• Electromagnetic energy

• Chemical energy

• Electrical energy

Tags

NGSS.MS-PS1-4

If heat is not flowing between Jesse's feet and the sand at the beach, which of the following must be true?

• The sand is wet.

• The sand is too cold for heat to flow.

• The sand is the same temperature as her feet.

• There is no friction between her feet and the sand.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

NGSS.MS-PS3-5

A ball rolls down and up a curved track. What can you expect from the ball's motion?

• The ball will roll as high as its starting point since energy cannot be created or destroyed.

• The ball will roll past its starting point and off the track since energy cannot be created or destroyed.

• The ball will roll back as high as a lower point from the starting point since some energy will be transformed to heat.

• The ball will roll as high as a point with the least potential energy.

Tags

NGSS.MS-PS3-1

NGSS.MS-PS3-2

NGSS.MS-PS3-4

NGSS.MS-PS3-5

What happens to turn the water vapor in Cassandra's breath into liquid water when she breathes on a cool window?

• Heat is added to the water vapor from the air.

• The temperature of the water vapor increases as it leaves her body.

• The water molecules spread apart as they touch the window.

• Heat leaves the water vapor as it touches the cool window.

Tags

NGSS.MS-PS1-4

Which hypothesis would NOT be tested using a controlled experiment?

• A geologist's hypothesis about how the Culpeper basin formed.

• A biologist's hypothesis that fertilizer increases grass growth.

• A biologist's hypothesis that temperature increases boost male reptile population.

• A geologist's hypothesis that acid rain weathers sedimentary rock faster than igneous rock.

Answer explanation

To carry out a fair test of a hypotheses we do a controlled experiment.

In a controlled experiment:

• - all the variables that can influence our outcome of the experiment are controlled (held constant).

• - the independent variable (test variable) is the only one changed

In a science class, each student performed the same experiment and shared their data. Tamara compared her data with her classmates'. What might indicate that her results are valid?

• Three other classes performed the same experiment.

• The experiment was repeated two years in a row.

• Many students recorded similar data to hers.

• A classmate reached a different conclusion.

To conduct an experiment to determine how many ice cubes are needed to keep a glass of water under 10 °C for 20 minutes. The experiment was repeated daily for a week. Why were multiple trials of the same experiment performed?

• To include additional variables in the experiment.

• To complete the experiment in less time.

• To find a cheaper way to conduct the experiment.

• To increase the accuracy of the results.