Review Unit 1

In 1897, Joseph Thomson discovered that atoms contained electrons. He proposed a change in the atomic theory of that time, and the theory was modified because of his discovery. Since Thomson’s discovery, atomic theory has been further modified. What is the best explanation for why scientific theories are modified?

• Theories more than ten years old are usually out of date.

• Scientists want to prove that the work of other scientists is wrong.

• New evidence that supports a change prompts scientists to modify earlier theories.

• So much information is available today that it is harder to focus research and disprove theories.

Scientific theories are based on

• general assumptions of how systems work.
• mathematical principles that can be proven true.
• large amounts of data collected over time.
• observations from within only one scientific discipline.

Tags

NGSS.MS-LS4-1

Scientific theories do not change once they have been written down.

• True
• False

Which of these explain how a natural phenomenon works or happens?

• theory

• law

Tags

NGSS.HS-ESS1-2

NGSS.HS-ESS1-5

NGSS.HS-ESS2-4

Which of these describes a natural phenomenon or relationship that always occurs under specific conditions

• theory

• law

Tags

NGSS.HS-PS2-1

A possible explanation to a problem that has not yet been tested. 

• data
• theory
• hypothesis
• fact

This part of the experiment serves as a basis of comparison; the one variable being tested has been omitted. 

• experimental group
• control group
• data
• variables

What step does every scientific experiment begin with?

• hypothesis
• question/problem
• procedures
• conclusion

An experiment is performed on plants to see how different liquids affect plant growth. Each plant in the experiment is given a different liquid; water, apple juice, or milk. Each plant has the same amount of soil, sunlight, and listens to the same music. In this investigation, the independent variable is ...

• The type of plant
• The amount of sunlight
• The type of music
• The type of liquid

Tags

NGSS.3-5-ETS1-3

The summary at the end of an experiment that explains the results. 

• conclusion
• procedures
• materials
• responding variable