8th Grade Science Midterm Reviewer

A researcher predicts that rewarding good behavior will positively influence the behavior of eighth-grade students. She asks a teacher to keep all her teaching practices the same from day to day, but begin rewarding good behavior, an approach known as "positive reinforcement." The researcher's results are shown below.

Which statement is the best conclusion based on these data?

• The results prove the researcher's prediction; positive reinforcement will always work.

• The results disprove the researcher's prediction; positive reinforcement will never work.

• The results support the researcher's prediction; the behavior of the students in this experiment improved when positive reinforcement was used.

• The results failed to support the researcher's prediction; the behavior of the students in this experiment did not improve when positive reinforcement was used.

How is a hypothesis beneficial even when it is NOT supported by the data?

• It leads to further investigations. 

• It helps scientists form a conclusion.

• It allows scientists to collect data from an experiment.

• It helps scientists decide how many times to repeat the investigation.

From his observations, Aristotle believed Earth was round and that the planets revolved around it. Approximately 1,500 years later, Nicolaus Copernicus evaluated astronomical data and suggested that Earth revolved around the Sun and that the planets' orbits were circular. Through scientific investigation, less than 100 years later, Johannes Kepler found that planets have elliptical orbits. What does this example demonstrate about scientific reasoning?

• Science is more subjective than objective.

• Scientific theories are proposed at random.

• Science is based on evidence and is open to change.

• Scientific concepts accepted today will be wrong in the future.

In science, what is the main difference between a law and a theory?

• Laws change frequently and theories rarely change. 

• Laws are factual statements and theories are just opinions.

• Laws provide rules for scientists to follow and theories are the ideas of scientists.

• Laws are observations of regular occurrences and theories are explanations for observations.

A teacher wants to layer these solutions in a tube. The liquid with the highest density will go first followed by another liquid and the least amount of density will be on the top. Based on the measurements of the various liquids, in what order should the teacher place the solutions in the tube?

• tap water, orange soda, maple syrup, corn syrup

• corn syrup, maple syrup, orange soda, tap water

• tap water, corn syrup, maple syrup, orange soda

• maple syrup, orange soda, corn syrup, tap water

Tags

NGSS.MS-PS1-2

Which of these lists correctly shows the phases of matter, in order from the state in which the atoms are least organized to most organized?

• solid, liquid, gas

• gas, solid, liquid

• solid, gas, liquid

• gas, liquid, solid

Tags

NGSS.MS-PS1-4

Some nonliving substances, such as gasoline, are made mostly of the same elements as lipids in living things. Both contain mostly carbon and hydrogen.

Which statement correctly explains how gasoline and lipids can be made of the same types of atoms?

• Atoms can combine in different ways.

• Atoms come together to form compounds.

• Atoms are the smallest unit of an element.

• Atoms contain different numbers of subatomic particles.

Tags

NGSS.MS-PS1-1

Look at the periodic table.

Which element would have chemical properties most similar to those of phosphorus (atomic #15) and why?

• sulfur, because both sulfur and phosphorus are solids

• lithium, because lithium is in the top row of the periodic table

• argon, because argon is at the end of the same row on the periodic table

• nitrogen, because nitrogen is located right above phosphorus in the periodic table

Tags

NGSS.MS-PS1-1

Audra is looking at a diagram of an atom. Which particle(s) does she see inside the nucleus?

• electrons only

• protons only

• electrons and protons

• protons and neutrons

If a sample of gold were reduced to the smallest possible particle of pure gold, which statement would most accurately describe the result?

• The sample would be reduced to atoms of gold.

• The sample would be reduced to molecules of gold.

• The sample would be reduced to protons and neutrons of gold.

• The sample would be reduced to electrons and protons of gold.

Tags

NGSS.MS-PS1-1