Scientific Method and Experimentation Worksheet

A student wants to investigate how the amount of salt in water affects its boiling point. They set up three beakers with 500 mL of water each. Beaker A has no salt, Beaker B has 10 grams of salt, and Beaker C has 20 grams of salt. They heat each beaker and record the temperature at which the water boils. Which of the following is the control group in this experiment?

• Beaker C (20 grams of salt)

• Beaker A (no salt)

• Beaker B (10 grams of salt)

• The thermometer used to measure the temperature

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A research team conducted an experiment on the effect of a new fertilizer on tomato plant growth. They divided 40 plants into four groups and measured their height over a month. They found that the plants given the new fertilizer grew 20% taller than the plants with no fertilizer. To make their results more reliable and generalizable, what should the researchers do next?

• Repeat the experiment with a different type of plant, such as basil.

• Repeat the experiment with only 10 plants.

• Change the type of soil they are using for the next experiment.

• Give the new fertilizer to all 40 plants in the next experiment.

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An online article claims that a new herbal supplement can cure the common cold. Which of the following sources would be the most reliable to verify this claim?

• A. A blog post by a user who says the supplement worked for them.

• B. An article in a popular health magazine that reviews the supplement.

• C. A study published in a peer-reviewed medical journal on the supplement's effects.

• D. The website of the company that manufactures the supplement.

A student sets up an experiment to test if plant seeds germinate faster in warmer temperatures. She places two identical pots with soil and seeds in two different rooms: one at 20°C and another at 25°C. She measures the time it takes for a sprout to appear in each pot. After two weeks, she concludes that seeds germinate faster at 25°C. What is a valid conclusion that can be drawn from this experiment?

• Seeds germinate faster at 25°C than at 20°C.

• All plants grow better at 25°C than at 20°C.

• Seeds will not germinate at 20°C.

• The experiment proves that temperature is the only factor affecting germination.

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Warmer temperatures cause all plant seeds to germinate faster.

• The seeds in the pot at 25°C took 14 days to germinate.

• The soil in both pots was too cold for the seeds to germinate.

• The seeds used in the experiment germinate faster at 25°C than at 20°C

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However, when other scientists tried to replicate the experiment, they could not achieve the same results. This situation is an example of what core principle of science?

• Scientific findings must be able to be replicated and verified by other researchers.

• Science is a process that relies on a single, groundbreaking discovery.

• The scientific method can only be used to study topics in biology.

• A new theory becomes a scientific law after only one successful experiment.

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A scientist observes that the population of penguins in a certain region has been decreasing for a decade. She notices that the average sea ice coverage has also been shrinking during the same period. She writes a paper suggesting that the shrinking sea ice is causing the penguin population to decline. This statement is an example of a(n):

• Hypothesis

• Observation

• Fact

• Inference

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A researcher is studying the effect of different amounts of sunlight on a certain type of algae. He grows three identical batches of algae under different light conditions: one batch receives 8 hours of light per day, another receives 12 hours, and the last receives 16 hours. After a week, he measures the algae growth. What is the dependent variable in this experiment?

• The length of the experiment (one week)

• The amount of algae growth

• The type of algae

• The amount of sunlight (hours of light)

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A group of students wants to determine if listening to music while studying affects test scores. They have one group study in a quiet room and another group study with music playing. Both groups take the same test. After analyzing the results, they conclude that there is no difference in test scores between the two groups. What would be a valid justification for this conclusion?

• The music was too loud to hear while studying.

• The students in both groups said they felt the same about their scores.

• The quiet group studied longer than the music group.

• They both got similar grades on the test.

A scientist is testing a new drug designed to lower blood pressure. She administers the drug to a group of 100 patients with high blood pressure and observes a decrease in their average blood pressure. To make the study's outcome more scientifically valid, which of the following procedures would be most important to add?

• Administer the drug for a shorter period of time.

• Conduct the experiment a second time on a smaller group of patients.

• Administer a placebo to a separate group of patients.

• Use a different drug to compare the effects.

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