CAST Science Practice Test

Front

Predict the changes in the sea urchin population as the kelp population increases.

Back

Sea urchin population decreases

Answer explanation

As the kelp population increases, it provides more food and habitat for sea urchin predators, leading to a decrease in the sea urchin population. Therefore, the correct answer is that the sea urchin population decreases.

Tags

NGSS.MS-LS2-1

Front

Use the graphs and the partial food web to predict the changes in the kelp population as the kelp population INCREASES. What will happen to the kelp population?

Back

Kelp population decreases

Answer explanation

As the kelp population increases, it may lead to overpopulation, resulting in resource depletion. This can cause a decrease in the kelp population due to competition and limited nutrients, making 'Kelp population decreases' the correct choice.

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-4

Front

A student conducts 5 trials to investigate factors affecting the formation of impact craters. The student drops a marble into a box with fine powder. Analyze the results in the graph pictured. Because the mass is 40g in each trial, mass is a...

Back

constant

Answer explanation

In this experiment, the mass of the marble is kept constant at 40g across all trials. This means it does not change and is not being tested as a variable, making it a constant in the investigation.

Tags

NGSS.MS-PS3-1

Front

A student conducts 5 trials to investigate factors affecting the formation of impact craters. The student drops a marble into a box with fine powder to measure the depth. Analyze the results in the graph pictured. Depth is the

Back

dependent variable

Answer explanation

In this experiment, the depth of the crater formed by the marble is measured as a response to the impact. Therefore, depth is the dependent variable, as it depends on the conditions of the trials.

Tags

NGSS.MS-PS3-1

Front

A student conducts 5 trials to investigate factors affecting the formation of impact craters. The student drops a marble into a box with fine powder at different speeds to measure the depth. Analyze the results in the graph pictured. Speed is the

Back

independent variable

Answer explanation

In this experiment, speed is the factor being manipulated to observe its effect on crater depth. Therefore, speed is the independent variable, as it is the variable that is changed to see how it influences the outcome.

Tags

NGSS.MS-PS3-1

Front

What is true about the results of the experiment on impact craters conducted by a student with 5 trials?

Back

As the speed of the marble increases, the depth of the crater increases

Answer explanation

The results indicate that as the speed of the marble increases, it impacts the surface with greater force, leading to a deeper crater. Therefore, the correct statement is that as the speed increases, the depth of the crater increases.

Tags

NGSS.MS-PS3-1

Front

A student conducts 5 trials to investigate factors affecting the formation of impact craters and here are the results. Which statement BEST describes the results of the investigation?

Back

The kinetic energy of the marble just before impact is proportional to the depth of the crater it forms

Answer explanation

The correct statement indicates that the kinetic energy of the marble, which is related to its speed and mass, directly influences the depth of the crater formed upon impact, demonstrating a clear relationship.

Tags

NGSS.MS-PS3-4

Front

Select a moon location in the model that supports the explanation that the New Moon phase explains why the disk becomes a ring.

Back

2

Answer explanation

Choice 2 shows the moon in the New Moon phase, where it is positioned between the Earth and the Sun. This alignment causes the illuminated part of the moon to be hidden, making the disk appear as a ring.

Tags

NGSS.MS-ESS1-1

Front

Why don't solar eclipses happen every month despite a new moon occurring?

Back

The model should show that the plane of the Moon's orbit around the Earth is inclined relative to the plane of Earth's orbit around the Sun.

Answer explanation

The model should show that the plane of the Moon's orbit around the Earth is inclined relative to the plane of Earth's orbit around the Sun. This inclination prevents solar eclipses from occurring every new moon.

Tags

NGSS.MS-ESS1-1

Front

Leah conducts two trials to identify a chemical reaction: Trial 1: SiO2 into H2O. Trial 2: AgNO3 into KCl. In which trial did a chemical reaction occur?

Back

Trial 2

Answer explanation

In Trial 1, silicon dioxide does not react with water, so no chemical reaction occurs. In Trial 2, silver nitrate and potassium chloride react to form a precipitate of silver chloride, indicating a chemical reaction.

Tags

NGSS.MS-PS1-2