Often, we think of science as something that only happens in laboratories where people where white lab coats and safety glasses. In reality, scientific processes are performed every day, by everyone. It's the process you go through when you try to solve a problem, like "Why isn't my car starting?" The steps you might take to answer this question are similar to the steps scientists might take to answer their questions. Most scientists agree to a common language of problem solving called "The Scientific Method," which is often described as a step-by-step methodology for solving problems. To be fair, there are many different ways to practice science, and not all of them use this procedure. For example, Jane Goodall did not use these exact steps to study chimpanzees in Gombe, but she incorporated many of the practices to help her understand chimpanzee behavior.
The following steps outline the general methodology for science process, but it is important to understand that not all research follows this orderly list. There are many different ways to do science!
You will use the scientific method to answer a question about human lung capacity. The volume of air in your lungs can be measured with a spirometer, which measures the air inhaled in mL (milliliters). Lung volume for an adult human is about 6000 mL, though not all the space is used for gas exchange. The maximum usable capacity of the lungs is called the vital capacity. There are many factors that could explain variations in the vital capacity of any two individuals.
Materials: Spirometer and mouthpieces, calculators, meter sticks or tape measures
Safety considerations: Students who have respiratory issues should not participate. If you at any time feel lightheaded, discontinue tests.
1. Make observations. Have several members use the spirometer. Write your observations on the summary sheet. Was everyone's vital capacity the same or were there variations?
2. Ask a question. Discuss wording for a causal question about your observations, write your question on the summary sheet. State a question related to lung volume and observations your made in #1.
3. Form hypothesis. You will be testing the relationship between chest circumference and lung capacity (volume). Make a prediction in the form of IF (repeat hypothesis) THEN (state prediction) statement.
4. Design the experiment. Considering your hypothesis…
a) State the independent variable
b) State the dependent variable
c) Do you have a control group? If so, what is it. If not, how will you test the hypothesis.
d) State your control variables (things that stayed the same between groups)
e) What additional considerations were made when designing your test?
5. Collect data. Construct a data table with appropriate labels and show the data you gathered. If you are testing the entire class, this may be a large amount of data. Attach a page to this one.
6. Organizing Data. When scientists have large amounts of data for individuals, they often chunk them into groups and take an average. It is possible that you have data points that are the same for individuals (some of your subjects may have the same chest circumference.) Group your data points into individuals with a SMALL, MEDIUM, and LARGE chest circumference. (Include with attachment.)
7. Graph the data. Graph the data using a bar graph that compares the three groups, using an average lung volume for each. The X axis is always the independent variable and the Y axis is the dependent variable. Be sure to label the graph and include units!
8. Draw Conclusions - To make a conclusion, you must look at the results of the test and decide whether your hypothesis was supported or rejected. Avoid using the word "prove" in your conclusions. All scientific knowledge is based on tentative or provisional knowledge, nothing is final. State your conclusion in a full sentence using the proper format and include a summary of the data. "The hypothesis that (repeat hypothesis) was (supported or not supported) because the data showed that… “
9. The experiment you did today has some flaws in its design. List other factors that may have influenced your results. Discuss how these uncontrolled variables may have affected your results.
10. If you were given another class period to redesign your test, what would you change?
11. Not all experiments have a control group, but experiments should always have a NULL hypothesis. What was the null hypothesis of this experiment.
12. We did not calculate the standard deviation for your data set. Do you think this information might be important? Why or why not?