Problem 24 - BIG IDEAS MATH Algebra 2: Common Core Student Edition 2015

Question

In Exercises 21–24, identify the method of data collection the situation describes. A researcher places bacteria samples in two different climates. The researcher then measures the bacteria growth in each sample after 3 days.

Step-by-Step Solution

Answer

The method of data collection used is an Experimental method.

Step 1: Understanding the Scenario

A researcher is performing an experiment with bacteria samples. The researcher places these samples in two different climates and then measures the growth after 3 days.

Step 2: Identifying the method

The data being collected here is the bacteria growth measured after 3 days from the two different climates.

Step 3: Method Conclusion

The method of data collection in this scenario is an Experimental method. In this method, the researcher controls the variables and observes if the change in one variable affects the other variable(not here in this case).

Key Concepts

Experimental Method

The experimental method is a fundamental approach to scientific inquiry. It is used when researchers want to explore whether a causal relationship exists between variables. The key feature of this method is the control and manipulation of variables. In a controlled experiment, one or more independent variables are changed to observe the effect on a dependent variable. Everything else is kept constant. This allows the researcher to infer causality from their observations.

For instance, in the scenario where a researcher places bacteria in two different climates, the climate is the independent variable, and bacteria growth is the dependent variable. By only changing the climate and keeping other factors the same, the researcher can conclude how climate influences bacterial growth.

• **Control Group**: A baseline group that is kept under standard conditions.
• **Experimental Group**: Receives the variable change, in this case, a different climate.

Bacteria Growth Measurement

Bacteria growth measurement is a vital process in microbiology, especially when assessing environmental impacts. Bacteria reproduce quickly, which makes them perfect subjects for experiments. Growth can be quantified in various ways, most commonly using methods like colony counting or assessing turbidity.

In the given exercise, the researcher measures growth after three days. Here’s how measurement might occur:

• **Colony Counting**: Counting the visible bacterial colonies that form on agar plates. Each colony arises from a single bacterium, providing an easy way to calculate growth.
• **Turbidity Measurement**: Involves measuring the cloudiness of a bacterial suspension. The more cloudy the solution, the more bacteria are present.

These methods can give precise data about how different environments affect bacterial proliferation. Accurate measurement is essential for drawing valid conclusions in experimental research.

Scientific Research Methodology

Scientific research methodologies provide structured ways to investigate questions, allowing results to be reliable and credible. The chosen method depends on the research question, available resources, and ethical considerations. For an experiment involving bacterial growth in different climates, elements of effective scientific methodology are essential:

• **Hypothesis**: A predicted outcome. In our scenario, this might be that bacteria grow faster in warmer climates.
• **Data Collection**: Conducting the experimental method appropriately includes collecting data in a controlled manner.
• **Analysis**: After data collection, it is analyzed to identify trends and validate the hypothesis. Statistical tools are often employed at this stage.
• **Conclusion**: Drawing insights from the data analysis that supports or refutes the hypothesis.

Each step is integral to deriving meaningful results from scientific inquiry, pushing forward our understanding of biological phenomena under different conditions.