Nature of Science FSA review

Scientists once thought that nothing could live at extreme depths in the oceans.  When tube worms were discovered living at the bottom of the sea, scientists

• dismissed this as a hoax immediately

• thought that the worms must have gotten there by accident

• studied the worms and changed their theories about whether life can exist at extreme depths

• moved the worms to a better place to live

Answer explanation

With new information (evidence), scientist will update (modify) the theory.

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Marco wants to design an experiment that will test whether a new plant food makes a grape vine produce more grapes.  What is the dependent (outcome) variable in this experiment?

• the amount of sun the vine receives

• the new plant food

• where the vine is planted

• the number of grapes produced

Answer explanation

Independent (test) variable is what you are changing on purpose in the experiment

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A class did an experiment to explore solubility and temperature.  Read the paragraph from one student's lab report.

"It was found that the solubility of NaCl went up as the water got warmer.  This was observed in all four trials.  A class discussion revealed that all other groups had similar results.  Based on research, it is hypothesized that the same relationship would be observed if a salt other than NaCl was used."

Which statement from the report refers to repetition?

• It was found that the solubility of NaCl went up as the water got warmer

• This was observed in all four trials

• A class discussion revealed that all other groups had similar results

• Based on research, it is hypothesized that the same relationship would be observed if a salt other than NaCl was used.

Answer explanation

Repetition is when one does an experiment several times. It is represented by the word trials.

A few hundred years ago, observations seemed to indicate an idea called spontaneous generation, which stated that living things could appear from nonliving things. In the seventeenth century, experiments were conducted that resulted in observations that disproved this idea. This led to the present-day idea that living things can only come from other living things. Which statement best describes what this change in ideas tells us about science?

• Science ideas do not need to be based only on factual and observable evidence

• Science knowledge changes because it is open to new evidence as it is discovered and observed.

• Science ideas are not accurate because they constantly change as new evidence is discovered

• Science is based on factual observations, so it should remain the same and not be changed over time.

Answer explanation

Science knowledge changes because it is open to new evidence as it is discovered and observed.-This is the essence of the standard

The image shows a design for a solar powered car.

What is the most likely reason the designers of this car would have needed to use research skills?

• The designers needed to calculate the speed at which the car is moving

• The designers needed to create a three-dimensional computer model of the car

• The designers needed to imagine new ways to implementing solar energy technology into cars

• The designers needed to determine which materials have previously been used to create similar cars.

Answer explanation

The use of technology is essential in the development and new discoveries within the different fields.

During several trials, a group of scientists tests the reaction of a new medicine on a strain of bacteria.  Which step is essential for proving the validity of the results?

• Make process public so the results can be replicated

• Change the procedures to check whether the same results take place

• Have another scientist check to make sure the medicine was properly produced

• Have each group member use a different medicine and see what happens when they test it on the bacteria

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Eric set his cactus plant out in the sunlight after it had been inside because he heard that sunlight was good for plants.  After a week, he notices that the cactus is growing flowers.  He wonders what caused the change.  He knows that the weather has been much warmer outside lately than the interior of his house, so he suspects that the cactus grew flowers after a temperature change.

Eric forms the hypothesis that if the temperature is increased significantly after being much cooler that cacti will begin to form flowers.  He tests this hypothesis with 20 identical cactus plants grown for a year inside a cool room.  He raises the temperature by 20 degrees in the room and then observes them to see if the blossoms form.

After repeating this experiment several times, no blossoms form on any of the plants after the temperature increase.  Which of these statements is MOST accurate?

• The hypothesis was not supported but is valuable because it shows that temperature is not the factor that caused the cacti to flower

• The hypothesis was not supported and therefore is not valuable; only a supported hypothesis has value

• .  The hypothesis was supported and is valuable; it shows the connection between temperature and flower formation in the cacti

• The hypothesis was supported but is not valuable because it only confirms an idea that is already understood

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Which choice best describes the difference between a law and a theory?

• A law is an observation of something that occurs. A theory explains why it occurs.

• A law is a description of the reason behind an event.  A theory tells about the event

• A law is an explanation known to be correct. A theory is something thought to be correct.

• A law is an idea that can be tested with an experiment.  a theory is an idea based on research

Answer explanation

scientific theory is a scientific explanation of why or how something occurs in the natural world. It is not a guess made by scientists, but is well-supported by evidence from many sources.

scientific law is a generalization of what happens and should apply in every situation throughout the universe.

A scientist claims that he made a discovery in the lab. What does the scientist need to have in order to prove that the discovery is valid?

• diagrams showing the steps used in the discovery

• accurate records that show that the data are consistent

• documents showing that the scientist is well known

• proof that the equipment used in the discovery is of high quality

Answer explanation

It's important for scientist to have accurate records.

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Students collected 10 corn seeds and planted them in the same kind of pots.  They used the same type and amount of soil in each pot.  They placed each pot in front of their classroom where the sun shines all day.  Everyday, for one month, they watered the seeds.  Half of the seeds were watered with 30 milliliters of water, the other half with 60 milliliters of water.  After one month, students measured how tall each plant grew.

Which hypothesis BEST matches the experiment listed above?

• The more fertilizer a seed receives, the taller it will grow

• The more sunlight a seed receives, the taller it will grow

• The more water a seed receives, the taller it will grow

• The more soil a seed is planted in, the taller it will grow

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