Eto Science

Scientists began exploring the ideas that make up the current atomic theory more than 2,500 years ago. Since

that time, many models of the atom that were once accepted by scientists have been abandoned and replaced.

Which explains why atomic models have changed over time?

• A model is abandoned when it is discovered to have limitations.

• New models have been developed as new information is discovered.

• The discovery of each new element requires the development of a new atomic model.

• Scientists discovered that models do not provide a useful way to show or explain scientific concepts.

Scientific knowledge is capable of lasting a long time. What makes scientific knowledge hold up so well over time?

• As new evidence is presented, scientific knowledge is open to revision.

• Scientific knowledge is published in well-respected journals, so it is easy to locate.

• Scientific knowledge is well researched and permanent.

• Once established, scientific laws cannot be broken or revised.

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Unprotected exposure to the sun’s rays is a factor in the development of skin cancer. Which of the following is

an example of empirical evidence that supports this hypothesis?

• a model of a skin cell showing where DNA is in the cell

• a skin cancer survivor’s recollection that he had a bad sunburn as a child

• data demonstrating a relationship between amount of sun exposure and incidences of skin cancer

• an advertisement for a sun block product that claims it protects skin for ultraviolet rays

Which best explains the difference between a scientific theory and a scientific law?

• Biologists develop theories; geologists develop laws.

• A law is based on evidence; a theory is based on ideas.

• A theory can become a law; a law cannot become a theory.

• A theory explains a set of observations; a law describes a pattern in nature.

A model can represent an object, system, or process. Why do all models have limitations?

• because all models are two-dimensional

• because a model includes every factor that affects it

• because a model is smaller than the thing it represents

• because a model is never exactly the same as the thing it represents

Which phrase defines a scientific theory?

• an untested idea

• an educated guess

• an accepted description

• a well-supported explanation

In which statement does the word theory mean scientific theory?

• In theory, the experiment will work as planned.

• She has a theory about why the storm arrived later than predicted.

• The atomic theory explains that material objects are made up of atoms.

• The doctor’s prescription for curing a cold is based on his best theory or guess.

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Cara read an article on why repetition and replication are so important, but she did not understand the difference between them. Which of the following best explains the two terms?

• Repetition is when a scientist repeats an experiment; replication is when a scientist conducts an experiment on genetic material.

• Repetition is when a scientist does the same experiment a number of times; replication is when other scientists reproduce a scientist’s experiment.

• Repetition is when a scientist publishes in more than one scientific periodical; replication is when another scientist reproduces another scientist’s results.

• Repetition is when a scientist commits an error in an experiment the first time and must repeat it; replication is when a scientist repeats an experiment to make sure it is valid.

Kaylee reads an article that states that the frequency of chirping by crickets is related to the temperature of

their environment. She wants to conduct an experiment to see if this is true. Kaylee states this hypothesis:

Crickets chirp more frequently when the temperature of their environment increases. What is the test

variable (independent variable) and outcome variable (dependent variable) in Kaylee’s experiment?

• test variable (independent variable): number of crickets; outcome variable (dependent variable): frequency of chirping

• test variable (independent variable): temperature of environment; outcome variable (dependent variable): frequency of chirping

• test variable (independent variable): number of crickets; outcome variable (dependent variable): temperature of environment

• test variable (independent variable): frequency of chirping; outcome variable (dependent variable): temperature of environment

Ty and Crystal are working together to learn about surface tension. They each add pennies to their own cup of water

to see how many they can add before the cup overflows. Ty is able to add 15 pennies. Crystal is able to add 38.

What should their next step be?

• They should discuss differences in their methods.

• They should each claim that their answer is right.

• They should record their results and move on to a different investigation.

• They should repeat the experiment using different pennies.