In Lesson 2, students explore questions in a scientific context. They consider what makes questions testable. Students evaluate questions and then pose testable questions about scientific problems. After reading short scenarios, students come up with their own testable questions about the reading. They also consider the types of evidence needed to answer their questions.
After completing this lesson, students will be able to
Consult the following sections in Information about the Process of Scientific Inquiry:
|1||No||Master 2.1, Working with Questions
(Make 1 copy per student and prepare an overhead transparency.)
|No materials except photocopies and transparencies|
|2||No||Master 2.2, Letters to the Editor
(Make 1 copy per student.)
Master 2.3, Question and Investigation Form
(Make 1 copy per student.)
|No materials except photocopies|
No preparations are needed except for making photocopies and transparencies.
Note to teachers: The goal of this lesson is to help students appreciate that although we all ask questions about the world, scientists ask questions in ways that are testable. The question, How is bug blood different from human blood? is an interesting one, and it does define a general problem. As stated, this question is not specific enough to be tested directly. However, one can ask a number of testable questions that can be investigated to produce data (evidence) that answer the more specific questions. For instance, a scientist might ask, “Do bug blood and human blood contain the same things? Do they contain the same kinds of cells? Do they contain the same chemicals?” Of course, there are some questions that simply ask for information. Are you going to the movies Saturday night? is a question that implies no problem about which testable questions can be asked.
In this module, students learn how to ask testable questions—questions that can be answered through investigations. The intention is not to present a complex set of criteria that define a scientific question, but rather to introduce students to the idea that scientists identify a problem, ask testable questions, collect and analyze evidence, and reach conclusions based on that evidence. If this module is taught near the beginning of the school year, it can serve as an introduction to scientific ways of thinking that students will practice and refine throughout the school year and into the future.
Students likely will respond, “To get answers or to get more information.”
Accept all answers. Write student responses on the board or on an overhead transparency. Some students may believe that good questions do not ask about something really obvious, ask only about things that are real, or allow us to gain necessary information. The objective is not to be overly critical, but rather to engage student thinking about questions.
Students’ answers will vary. Write some of their responses on the board. Try to elicit the following characteristics of questions that are not scientifically testable:
Each question defines a general problem. As written, none of the questions is directly testable. Two of the questions (3 and 6) are not appropriate for a scientific investigation because they involve personal preference (Question 3) and moral values (Question 6). The other questions are appropriate to scientific investigation but need to be rephrased in a more specific form.
To get students started, give them one example of a testable question such as, Does what you eat influence the appearance of pimples? or, Does eating chocolate contribute to acne?
Give student teams 5 to 10 minutes to work with their questions. Students probably do not have the background to generate questions that show insight into each of the scientific problems. Students working with the same question may ask different testable questions. The purpose of this step is to develop critical-thinking skills and to give students practice writing testable questions. Because the purpose of this lesson is to develop students’ understanding of testable questions, avoid critiquing the problems they identify. Instead, focus on the students’ ability to phrase a question in a way that makes it testable. Look for questions that focus on the natural world, scientific ideas, and quantitative relationships. Questions should not relate to personal beliefs, moral values, or the supernatural.
Write the teams’ questions on the board or a transparency. As questions are put on the board, ask students if they agree that the question is testable. If they do not agree, ask that they restate the question so that it is testable.
Note to teachers: Questions 3 (Is rock music better than hip-hop music?) and 6 (Is vegetarianism better than eating meat?) imply a preference and as such are not testable. However, when students are confronted with questions expressing or implying a preference, they should probe deeper to be able to generate a testable question. For instance, if students are told or if they read that vegetarian diets are better than meat-containing diets, they might begin by asking, “Better in what ways?” This may lead to the notion that one diet is better than another in terms of nutritional content or long-term health consequences. From these clarifications, students can generate testable questions. Students can treat the issue of “better music” in a similar manner. In what ways might one type of music be better than another? Does one produce greater sales or greater alertness?
Tip from the field test: Some questions generated by teachers for this activity include the following:
A teacher-generated question related to Question 5 on Master 2.1 was considered “subjective.” This question was changed so that its answer doesn’t rely on asking people a general question about their own feelings. These examples point out what you should look for with your students’ questions: are they stated specifically enough to be tested as stated, or are they too general and not testable directly? If a question is too “big,” students may have to break off a smaller piece in the form of a more specific question.
Guide the discussion to focus on the following criteria:
Note to teachers: Students need to come away with the understanding that scientifically testable questions are centered on objects and phenomena in the natural world. These objects and phenomena can be described and explained by scientific investigations. Testable questions do not relate to the supernatural. Testable questions lead to scientific investigations that gather measurable evidence. Mention to students that different kinds of investigations may be appropriate depending on the question. Some questions lead to observations, while others lead to experiments.
Note to teachers: In Activity 2, students practice analyzing readings and writing questions as an introduction to the next lesson. This activity provides an opportunity to assess students’ understanding of testable questions. To save time, you may select just one of the readings and discuss it with the class. Alternatively, you may assign the activity as homework.
Look for questions that meet the criteria given in Step 8 of Activity 1. Student questions should be worded in a way that suggests that they can be answered through investigations. Their questions should not be based on opinions or personal beliefs. Examples of acceptable questions and investigations follow.
Example Question: Does food served at Quick and Tasty contain chemicals that can lead to cancer?
Example Investigation: Test food from Quick and Tasty for chemicals that are associated with cancer.
Example Question: Is cancer more common today than in the past?
Example Investigation: Compare the incidences of several types of cancer today and 20 or 50 years ago.
Example Question: Do obese people select different food items at Quick and Tasty compared with people of normal weights?
Example Investigation: Observe and record the food choices at Quick and Tasty of obese and normal-weight people.
Example Question: Are the salads served at Quick and Tasty as nutritious as similar salads served at more expensive restaurants?
Example Investigation: Obtain comparable salads from Quick and Tasty and several more expensive restaurants. Analyze them for their nutritive content.
Example Question: Does a typical meal at Quick and Tasty contain more calories than recommended for an average person?
Example Investigation: Determine the number of calories in several of the Quick and Tasty meals and compare this with recommended calorie intakes.
Example Question: Are the food portions served at Quick and Tasty larger than those recommended for a healthy diet?
Example Investigation: Obtain various food items from Quick and Tasty. Compare their portion sizes with the recommended ones.
|Activity 1: What’s the Question?|
|What the Teacher Does||Procedure Reference|
Remind students that they asked questions about cubes during the first lesson. Ask,
Explain that scientists ask questions that are answerable through scientific investigations.
|Steps 2 and 3|
Divide the class into teams of 3. Give each student a copy of Master 2.1, Working with Questions.
Explain that questions may have to be rephrased in the form of a more specific question that can be tested through investigation.
Assign each team a question from Master 2.1. Ask teams to
Reconvene the class. Ask several teams to share their conclusions.
Ask students to list characteristics that distinguish testable questions from questions that cannot be tested.
|Activity 2: Questions … More Questions|
|What the Teacher Does||Procedure Reference|
Give each student a copy of Master 2.2, Letters to the Editor, and Master 2.3, Question and Investigation Form.
Instruct students to
|= Involves copying a master.|
|= Involves making a transparency.|