2019 Semester Exam Review

Controlled scientific experiments include variables. One kind of variable is an independent variable and the other is a dependent variable. Which statement best describes the difference between an independent variable and a dependent variable?

• The dependent variable does not change and the independent variable does change.

• The dependent variable is the control and the independent variable is the result.

• The independent variable does not change and the dependent variable does not change.

• The dependent variable changes based on the independent variable.

Tags

NGSS.MS-PS2-2

Which type of investigation is most likely an experimental investigation?

• Using a hand lens to examine four different rocks

• Testing how far a marble will roll depending on ramp height.

• Measuring the width of a desk with a meter stick.

• Observing cells under a microscope.

Which of the claims about why many experiments include several trials instead of a single trial is correct?

• Repetition of trials increases the sample size of the experiment

• Repetition of trials makes data easier to analyze

• Repetition of trials increases the accuracy of results

• Repetition of trials lets the scientist change the experimental procedure

Tags

NGSS.MS-PS1-2

A lab group is measuring how many drops of water can fit on a coin. Each group follows the same procedures. How will following the same procedures affect the students’ investigation?

• They will get reliable results that can be compared

• They will be able to skip steps and finish quickly

• They will be able to take turns more easily

• They will be more likely to make mistakes

Scientists can use many strategies during investigations, including observations, fieldwork, surveys, models, and experiments. Which of these phrases best describes an experiment?

• Collection of data from an uncontrolled environment for comparative purposes.

• Observation of animals in the natural world.

• Procedure with controlled conditions and test.

• Mathematical analysis of data.

Tags

NGSS.MS-PS2-2

NGSS.MS-PS3-4

A scientist used a computer model to predict the path of a hurricane. The hurricane followed a similar path but did not follow the exact path predicted. How does this example demonstrate a limitation of models?

• Models can be used to predict weather events before the events occur.

• Models cannot be used to predict things.

• Models can only be used to show physical structures, not events such as hurricanes.

• Models cannot account for how every factor may suddenly change.

Tags

NGSS.MS-ESS2-5

NGSS.MS-ESS3-2

Lab groups use different methods to measure the volume of the same metal cube as shown in the picture above. What do both of these investigations show even though different methods were used?

• Different methods can have the same results.

• Different groups must perform investigations using different methods.

• Different methods will have different results.

• Some groups do less work by using different methods.

Avery did some research about classification for a science report. She learned that until 150 years ago scientists recognized only two groups of organisms: plants and animals. Now, scientists also recognize several groups of microscopic organisms. How should Avery explain the reasoning behind why scientists decided to classify organisms into more groups?

• Scientists invent new organisms that need to be classified.

• Scientists continue to learn more about living things.

• Fewer organisms have gone extinct in recent years.

• More types of organisms exist now.

Which statement best explains why scientific knowledge improves over time?

• Scientific experiments can be repeated under different conditions with the same results.

• Scientific ideas change as new information is collected and interpreted.

• Scientific data can be interpreted differently based on personal beliefs.

• Scientific theories are considered laws once they are proven by many scientists.

Keesha did an experiment to study the rate of photosynthesis in the water plant Elodea. She placed a piece of Elodea in a beaker of water and set the beaker 10 centimeters (cm) from a light source. Keesha counted the bubbles released from the plant every minute for five minutes (min). She repeated the process two more times. First, she moved the light to 20 cm from the beaker, and then she moved the light to 30 cm from the beaker. Keesha’s setup and data are shown below. What is the outcome variable (dependent variable) in this experiment?

• The distance of the light source from the plant

• The type of plant placed in the beaker

• The amount of time the bubbles were counted

• The number of bubbles produced

Tags

NGSS.MS-LS1-6