SC.8.N.1.1

Students swung three pendulums of different lengths back and forth ten times and recorded the finish times of each. Which of the following describes the “type of string” used in the experiment?

• Control group

• Control (constant) variable

• Test (independent) variable

• Outcome (dependent) variable

Answer explanation

The type of string used in the experiment is a control (constant) variable because it remains unchanged throughout the trials, ensuring that any differences in finish times are due to the pendulum lengths, not the string.

Tags

NGSS.MS-PS2-2

The following statements were taken from the procedures of four different investigations. Which of the investigation statements describes the process of repetition?

• Investigation 1

• Investigation 2

• Investigation 3

• Investigation 4

Answer explanation

Investigation 4 describes the process of repetition, which involves conducting the same experiment multiple times to verify results. This is essential for ensuring reliability and accuracy in scientific investigations.

Tags

NGSS.MS-ETS1-4

Colleen waters the plants in her greenhouse once every day. She wants to find out if the plants will grow more leaves if they are watered more often. She counts the number of leaves on each plant before she starts. She then continues to water half of the plants once daily, but she waters the other half twice a day. What is the outcome variable (dependent variable) in Colleen's experiment?

• The type of plant being grown

• The number of leaves the plants grow

• The amount of light the plants receive

• The number of times the plants are watered

Answer explanation

The outcome variable in Colleen's experiment is the number of leaves the plants grow, as it measures the effect of different watering frequencies on plant growth.

Tags

NGSS.MS-LS1-5

NGSS.MS-LS2-1

NGSS.MS-LS2-4

Dr. Jordan makes a discovery and publishes the results for other scientists to read. Dr. Keisha tries to repeat the experiment and cannot make it work. Her results are also published. This prompts Dr. Jordan to review his experimental results again and finds that his discovery only works under certain conditions. He publishes the change. Dr. Keisha repeats the new method and finds the same results as Dr. Jordan, but another scientist, Dr. Winslow, gets different results. What does this story demonstrate?

• Scientific knowledge results from a lot of debate and confirmation.

• Scientific knowledge is developed by individual scientists in isolation.

• Scientists consistently disagree with each other during experimentation.

• Scientists consistently share common interpretations of data and information.

Answer explanation

This story illustrates that scientific knowledge is built through debate and confirmation, as seen when Dr. Jordan revises his findings after Dr. Keisha's attempts, highlighting the collaborative nature of scientific inquiry.

Tags

NGSS.MS-PS2-5

You are testing how well different dish soaps clean grease. What is the test variable (independent variable) in your experiment?

• Amount of water used

• Type of dish soap used

• Number of dishes cleaned

• Amount of grease left behind

Answer explanation

The test variable, or independent variable, is what you change in an experiment. In this case, the type of dish soap used is what you are testing to see how it affects grease cleaning, making it the correct choice.

How many variables should be allowed to change in a well-designed, controlled experiment?

• One

• None

• It varies.

• Two or more

Answer explanation

In a well-designed, controlled experiment, only one variable should be allowed to change at a time. This ensures that any observed effects can be directly attributed to that variable, making the results clear and reliable.

Tags

NGSS.MS-PS2-2

• the independent variable is distance
• the independent variable is d=25 t
• the dependent variable is time
• the dependent variable is distance

Ms. S set up an experiment to see how the mass of a ball affects the distance it rolls off a ramp. What is the dependent variable?

• Distance traveled by the ball

• Height of the ramp

• Mass of the ball

• Where the experiment took place.

On a graph, which axis shows the dependent variable?

• x-axis

• y-axis

• neither

• it changes

Time is the _____________ variable.

• dependent

• independent