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The Scientific Method in Biology — Reading Comprehension

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MS-LS1-1

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This passage provides an in-depth look at how the scientific method is applied in biological investigations for students in grades 6-8. Aligned with NGSS standard MS-LS1-1, it covers each step of the scientific process, including observation, hypothesis formation, experimentation, data collection, and analysis. Real-world examples such as plant growth experiments and animal behavior studies are featured, along with a discussion of variables and the importance of controlled experiments. The text also addresses the unique challenges of biological research, such as ethical considerations, organism variability, and timeframes for results. Activities include comprehension questions, writing prompts, and graphic organizers to support diverse learners. This resource is audio integrated, supporting accessibility and multimodal learning. Key science vocabulary is highlighted, and Spanish translations are provided for both the main and simplified texts.

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microscope, investigation, scientific, laboratory, biology, microscope, microscope, microscope, microscope, microscope, investigation, laboratory, laboratory, laboratory, laboratory, biology — Biology seeks to answer questions about living things using a careful process called the scientific method. Image by fernandozhiminaicela / Pixabay.

Biology seeks to answer questions about living things using a careful process called the scientific method. For example, a scientist may notice that some plants grow taller near a window than others placed farther away. To understand why this happens, scientists follow a series of logical steps: making observations, forming a hypothesis, designing and conducting experiments, collecting and analyzing data, and drawing a conclusion. Applying this process helps ensure discoveries are based on evidence, not just guesses or opinions.

How the Scientific Method Works

The first step is observation—scientists gather information using their senses or tools. For instance, they might measure how fast plants grow under different light conditions. Next, they create a hypothesis: a testable explanation for what they observed. In our plant example, a hypothesis could be, "Plants exposed to more sunlight will grow taller than those given less light." To test the hypothesis, the scientist sets up a controlled experiment where only one variable—the amount of light—is changed, while all other factors like water, soil, and temperature remain constant. This helps ensure that any differences in plant growth are actually caused by light, not something else. Data is collected—usually through measurements or observations—and then analyzed to see if it supports or contradicts the hypothesis.

Applying the Method in Real-World Biology

Biologists use the scientific method to answer questions in many areas, from plant growth to animal behavior. In animal studies, researchers might observe how changes in food availability affect foraging habits in birds. Variables like the type or amount of food offered are carefully controlled. Sometimes, hundreds of animals or plants are observed to account for variability among living things. Data is often organized in tables or graphs to spot patterns and trends. For example, if plants in sunlight grow 25% faster than those in shade, the data provides clear evidence supporting the hypothesis. In some cases, unexpected results lead to new questions and further experiments, showing how science is a continuous, self-correcting process.

Challenges Unique to Biological Research

Studying living organisms brings special challenges. Unlike chemicals in a test tube, living things are highly variable and can change over time. Biological experiments often require large sample sizes and may take weeks, months, or even years to complete. Ethical considerations are important, especially when working with animals or humans. Scientists must design experiments that minimize harm and respect living creatures. Sometimes, natural events like disease or weather can affect results, requiring careful analysis and sometimes repeating experiments.

By following the scientific method, scientists make discoveries that help us understand life’s complexity and solve real-world problems, from improving crop yields to protecting endangered species. This approach is central to how we build new knowledge in biology and connect it to broader scientific principles, like cause and effect in living systems.

Interesting Fact: Some plant experiments, such as studying tree growth, can last for decades or even centuries, with data collected by multiple generations of scientists!

Which of the following is the best example of a hypothesis?

Plants exposed to more sunlight will grow taller than those given less light.All plants need water.Measuring plant height.Graphs show plant growth.

What is the purpose of a controlled experiment?

To change many variables at once.To test the effect of only one variable.To guess the answer.To avoid collecting data.

In the passage, what is the first step of the scientific method?

Drawing a conclusionMaking a hypothesisMaking observationsAnalyzing data

Which step comes after collecting data in the scientific method?

Forming a hypothesisAnalyzing the dataMaking an observationControlling variables

What does the word 'variability' mean in the passage?

The amount of sunlight a plant getsDifferences among living things or resultsA type of scientific toolA prediction about an experiment

What is the meaning of 'ethical considerations' as used in the passage?

The amount of data collectedRules about what is right or wrong in experimentsThe speed of plant growthA kind of experiment

Why do scientists use large sample sizes in biology experiments?

To make results more accurate despite differences among living things.To make the experiment shorter.Because it is easier to work with many subjects.To avoid collecting data.

How might natural events, like weather, impact biological experiments?

They can change results, requiring careful analysis or repeating experiments.They make experiments easier.They always help scientists get the results they want.They have no effect on experiments.

True or False: In a controlled experiment, more than one variable is changed at a time.

TrueFalse

True or False: The scientific method is only used in chemistry, not biology.

TrueFalse