Doing Science: The Process of Scientific Inquiry
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National Institute of General Medical Sciences

Doing Science: The Process of Scientific Inquiry

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Teacher's Guide

Lesson 3—Explain/Elaborate

Conducting a Scientific Investigation (Page 2 of 2)

Procedure

Activity 2: What’s the Cause?

Note to teachers: Make sure that students have available their Investigative Report Form from the previous activity. This helps them recall the progress of their investigation.

  1. Explain to the class that they will continue their investigation into the school absences among band members at Truman and Jackson middle schools. Specifically, they will answer the questions that were asked at the conclusion of Activity 1:
  1. Give each student one copy of Master 3.1, Investigative Report Form. Instruct students to write the testable questions developed at the end of the previous activity in the “Testable Question” space on their form.
  2. Reconvene students in their teams from Activity 1. Display an overhead transparency of Master 3.5, Second Memo from Director. Read the memo aloud to the class.
National Science Education Standards icon
Content Standard A:
Use mathematics in all aspects of scientific inquiry.
  1. Give each team one copy of Master 3.6, Interview Summary, and Masters 3.7a and b, Quotes from Interviews. Instruct students to review the information.

Information in the tables came from interviews with the students’ parents. The table for Truman Middle School shows that there were 10 students from band class absent during the past week. One student was away on a family vacation. The other nine students all have an illness that displays stomach-related symptoms. The table for Jackson Middle School lists eight absent students. One student has a broken leg. The remaining seven students have an illness that presents stomach-related symptoms.

The quotes from the parent interviews report the same symptoms listed in the tables. Some parents volunteer reasons for the illnesses such as food poisoning or the flu. These conflicting reasons may confuse some students. You may point out that the reasons given by the parents are opinions and not diagnoses from a doctor, which are derived from medical evidence. A subtle but important point is made by a healthcare worker during one of the parent interviews. The worker mentions that with food poisoning, a person becomes ill in a day or two, while a stomach virus takes about five days before the illness strikes. Students should use this information to decide what type of illness may be associated with which activities of the band members.

  1. Give each team one copy of Masters 3.8a–d, School Calendars. Instruct students to review the information.

Circulate among the teams as they look at the school calendars. Remind students that they are looking for evidence that will help them develop better explanations about the cause of the health problem. Make sure that students understand why they are looking at the school calendars. An illness is involved. If there are contacts between students from the two schools, then such contacts may help explain how an illness was contracted or passed from student to student.

National Science Education Standards icon
Content Standard A:
Think critically and logically to make relationships between evidence and explanations.
  1. Have students compare the two school calendars and write down their conclusions.

A comparison of the Truman and Jackson middle school calendars reveals that the seventh-grade bands from both schools were together three times in the past month:

National Science Education Standards icon
Content Standard A:
Develop descriptions, explanations, predictions, and models using evidence.
  1. Acting as team supervisor, facilitate a class discussion to summarize the findings from all the teams. Think ahead to the next steps for the investigation. Guide the discussion to focus on the following questions:

Encourage students to ask questions about the activities the band members might have participated in during the planning meeting and at the Battle of the Bands. Students should be concerned about activities the sick band members have in common. If not brought out by a student, call attention to the fact that people become sick about five days after being exposed to a stomach virus, while they become sick the next day or two after eating contaminated food.

National Science Education Standards icon
Content Standard C:
Some diseases are the result of intrinsic failures of the system. Others are the result of damage by infection by other organisms.

At this point, we can speculate that students were either exposed to a stomach virus during the planning meeting or to food poisoning at the Battle of the Bands. Students will be provided with details about band activities in Activity 3.

Activity 3: What’s the Source?

Note to teachers: Make sure that students have available their Investigative Report Forms from the previous two activities. This helps them recall the progress of their investigation.

  1. Explain to the class that they will continue their investigation into the school absences among band members at Truman and Jackson middle schools. Specifically, they will explore the activities students were engaged in during the Battle of the Bands event to see whether they can pinpoint how the students became ill.
  2. Give each student one copy of Master 3.1, Investigative Report Form. Instruct them to write the testable questions developed at the end of the previous activity in the “Testable Question” space on their form.
  3. Continue with students in the same teams as in the previous activities. Display a transparency of Master 3.9, Third Memo from Director. Read the memo aloud to the class.

The memo informs the teams that a nearby community has reported that its water supply may be contaminated by bacteria that cause a stomach-related illness.

tip iconTip from the field test: The students’ knowledge about disease transmission is limited. Make sure that they understand that food poisoning and illness from contaminated water are not contagious. However, a stomach virus can be passed from one person to another.


  1. Give each team one copy of Masters 3.10a and b, Activity Tables. Ask students to review the information and record their findings on their Investigative Report Form.

The Activity Tables provide information about the activities that band members from both schools participated in on the day of the Battle of the Bands event. The tables include information about activity participation by band members who became ill and those who did not become ill.

National Science Education Standards icon
Content Standard A:
Recognize and analyze alternative explanations and predictions.

Content Standard E:
Science and technology are reciprocal. Science helps drive technology. Technology is essential to science.

Content Standard A:
Communicate scientific procedures and explanations.
  1. Give each team one copy of Masters 3.11a and b, Activity Maps. Ask students to review the information and record their findings on their Investigative Report Form.

The Activity Maps show the street locations for the various student activities. The maps depict

  1. Instruct the teams to record their conclusions about which activities may have exposed the students to disease. They should be prepared to share their conclusions with the other teams.

Analysis of the activity data suggests that either eating at the Cheep Chicken Hut restaurant or swimming in the lake made the band members ill.

  1. Acting as team supervisor, facilitate a class discussion to summarize the findings from all the teams. Guide the discussion to focus on how the teams think the band members became ill. Ask the teams to explain their evidence and reasoning.

Students should conclude from their analyses of the activity tables that two possibilities exist: 1) students got food poisoning at the Cheep Chicken Hut and 2) students were infected while swimming in the lake. Without additional information, it is not possible to eliminate either possibility from suspicion. A third possibility also exists. Students could have contracted a stomach virus while attending the planning meeting on May 15. Explain to students that the process they followed is similar to that used by scientists conducting an investigation. Investigations do not always reach a single conclusion. They often raise more questions that need to be investigated.

  1. Ask students to consider what next steps they would take to reach a firm conclusion about the cause of the student illnesses. What evidence would they like to collect?

Students’ suggestions may include

assessment icon
Assessment:
Use the completed Investigative Report Forms as a summative assessment.
  1. Collect from students their three Investigative Report Forms.

These can be used as an assessment tool.

Activity 4: Reflecting on the Process of Scientific Inquiry

Note to teachers: Make sure that students have available their Investigative Report Forms from the previous three activities. This helps them recall the progress of their investigation.

  1. Explain to the class that they will review the process used during the community health department investigation from the previous activity. Ask, “How did your investigation begin?”
National Science Education Standards icon
Content Standard G:
Science requires different abilities, depending on such factors as the field of study and type of inquiry.

Student responses will vary. Bring out the idea that the investigation began with a problem that prompted the asking of a testable question.

  1. Ask students, “What testable question began your investigation?”

Students will report different questions. Appropriate questions deal with whether or not the school absences noticed by the principal are unusually high. Students may have asked a question such as, Is the number of school absences in the last week more than in previous weeks?

  1. Ask students, “As your investigation went along, did you ask other testable questions? What were they?” Write their questions on the board.

Students will report a number of different questions. Try to guide the discussion so that the questions are brought up in the order that they appear in the investigation. Examples of questions that students may report are the following:

  1. Next, turn the discussion to the collection and analysis of evidence. Ask students, “What evidence did you collect and analyze to answer your questions?”

Students will mention various types of evidence collected.

  1. Ask, “Was all of the evidence you analyzed helpful in answering your questions?”

Student responses will vary. Some will report that all evidence was helpful in that it helped them answer a question or choose between alternative explanations. Other students may feel that some evidence was not helpful because it could not definitively answer their question.

National Science Education Standards icon
Content Standard A:
Recognize and analyze alternative explanations and predictions. Communicate scientific procedures and explanations.
  1. Explain to students that they will now reconsider the evidence used in their investigation, consider what information the evidence provided, and explain how that evidence was used to answer a question or to choose between alternative explanations.
  1. Give each student one copy of Master 3.12, Analyzing Evidence. Explain that they have about 15 minutes to

While the students are working, circulate among them and guide their progress. Some students may not understand why some pieces of evidence were included in the investigation. For example, the interviews with the parents of the sick students are necessary to confirm their reasons for absence from school.

  1. After students have completed their work on Master 3.12, ask for volunteers to share their answers with the class.
assessment icon
Assessment:
Assess students’ understanding by listening to their explanations and reasoning.

As students report their answers, guide the discussion to raise the points made in the following sample answers for Master 3.12.

  1. Memos from the director of the community health department

The first memo suggests a possible health problem at a local school. The second memo provides access to information about the student absences and student band activities. The third memo raises the possibility that the local water supply is contaminated.

  1. Attendance data for seventh-grade students at four middle schools

The attendance data reveal that students in band classes at Truman and Jackson middle schools were absent during the past week at rates several times higher than normal. This is considered to be evidence of a possible health problem. It remains possible, however, that all or some of the absent students were missing from school for reasons other than illness.

  1. Summaries of interviews from parents of absent students

Interviews with parents of the missing students confirmed that the students were indeed absent from school and supply reasons for their absences. The parent information summarized in the tables indicates that all but two of the missing students were ill with a stomach-related illness. This information rules out the explanation that students were absent from school because they were truant.

  1. Transcripts from interviews with parents of absent students

The interviews with parents provide additional information about the student absences. For example, one parent states that her child has the flu while another attributes his child’s illness to food poisoning. These comments are included to suggest possible causes for the illnesses. These comments are opinions, however, and must not be treated as necessarily factual.

We also learn from the interviews that it usually takes about five days to become sick after being exposed to a stomach virus. In contrast, a person who eats contaminated food usually gets sick within the next day or two. This information becomes important when trying to decide which contacts between students from the two schools might be associated with the illnesses. For example, a stomach virus may have been contracted from sick students at the planning meeting or stomach illness may have been spread during an activity at the band event such as swimming in contaminated water or eating contaminated food.

  1. School calendars

Since the available evidence suggests that the absent students may all be suffering from the same illness, it is important to investigate whether the affected students from the two schools were in recent contact with each other. Such contacts provide opportunities for a disease-causing organism to pass among the students. Assuming that eating is involved, such shared experiences are also consistent with illness resulting from food poisoning.

A comparison of the school calendars reveals that band students from the two schools came into contact with each other three times in the past month. The first occasion was the May Day parade on May 5. It is unlikely that the illnesses resulted from this contact because it occurred so long ago. Further supporting this view is the fact that the band from Roosevelt Middle School also attended the parade but its students did not become ill.

National Science Education Standards icon
Content Standard F:
The potential for accidents and the existence of hazards imposes the need for injury prevention. Important personal and social decisions are made based on perceptions of benefits and risks.

Students from the two bands were also together for the Battle of the Bands planning meeting held on May 15. It is possible that a student with a stomach virus spread the illness to others at this meeting. Assuming that students would become sick five days later, they would be absent from school starting on May 20, which is what was observed. Students from the two schools also were together at the Battle of the Bands event on May 19. It is possible that students ate contaminated food at the event and became sick the next day.

  1. Student activity tables

At this point, the most likely explanation for why the students became ill is that they either contracted a stomach virus at the planning meeting or got food poisoning at the Battle of the Bands. These tables provide information about which students participated in which activities at the Battle of the Bands. This information may help identify a source of exposure to a disease-causing organism. Information from the tables reveals that the majority of students who became ill ate at the Cheep Chicken Hut restaurant and swam in the lake. This means that students may have eaten contaminated food at the restaurant. It also raises the possibility that students became ill by swimming in contaminated water. Consistent with this new possibility is information contained in the third memo from the health department director, which mentions that a nearby community suspects that its water supply is contaminated with bacteria that cause a stomach-related illness.

  1. Activity maps

These maps show where the various activities associated with the Battle of the Bands event took place. The final map depicts the activities attended by students from both schools who later became ill. This information suggests that the illnesses were related to eating at the Cheep Chicken Hut restaurant or swimming in the lake.

  1. Explain that in the next lesson, students will continue in their roles as members of the investigative team. They will take charge of another investigation dealing with a community health problem.
Web activity icon Lesson 3 Organizer: Web Version
Activity 1: Unusual Absences
What the Teacher Does Procedure Reference

Explain to students that they will carry out a scientific investigation. They will be working as members of an investigative team from the local community health department.

Step 1

Give each student one copy of Master 3.1, Investigative Report Form.

master iconStep 2

Divide the class into teams of three and direct them to computers. Have students log onto the Web site and click on “Activity 1—Unusual Absences.”

Step 3

Instruct teams to read the new message and come up with a testable question about the student absences.

Steps 4 and 5

Instruct teams to click on the link to the school district Web site and

  • export the attendance data to the community health department Web site,
  • display the data in graphic form,
  • analyze the graphs and record their findings on Master 3.1, and
  • when finished, log off the Web site.
Steps 6–9

Facilitate a class discussion. Focus on the following questions:

  • What is the reason for the higher number of absences among students in band class at Truman and Jackson middle schools?
  • If these absences are due to an illness, do band members from the two affected schools share the same symptoms?
  • Have band members from the two schools been in contact with each other?
Step 10
Activity 2: What’s the Cause?
What the Teacher Does Procedure Reference

Explain that teams will continue their investigations, focusing on the questions asked at the end of the previous activity.

Step 1

Give each student one copy of Master 3.1, Investigative Report Form. Instruct students to write down the testable questions asked during the last activity.

master iconStep 2

Direct each team to a computer and have them log onto the Web site and click on “Activity 2—What’s the Cause?”

Step 3

Instruct teams to

  • read the new message,
  • read the results of interviews,
  • read the available portions of the parent interviews, and
  • record their findings on Master 3.1.
Steps 4–6

Instruct teams to compare the two school calendars and record their findings on Master 3.1.

  • When finished, teams should log off the Web site.
Steps 7 and 8

Facilitate a class discussion. Focus on the following questions:

  • Is there a common reason for the absences of the band students at Truman and Jackson middle schools?
  • What are possible causes for the student illnesses?
  • How could students from both bands be exposed to a disease-causing organism at the same time?
  • Assuming that the students from the two bands are suffering from the same illness, when were they most likely exposed to the disease-causing organism?
Step 9
Activity 3: What’s the Source?
What the Teacher Does Procedure Reference

Explain that teams will continue their investigations, focusing on the questions asked at the end of the previous activity.

Step 1

Give each student one copy of Master 3.1, Investigative Report Form. Instruct students to write down the testable questions asked during the last activity.

master iconStep 2

Direct teams to computers. Have students log onto the Web site and click on “Activity 3—What’s the Source?”

Step 3

Instruct teams to

  • read “New Message,”
  • examine “Activity Tables,”
  • examine “Activity Maps,”
  • record their findings on Master 3.1, and
  • when finished, log off the Web site.
Steps 4–7

Facilitate a class discussion to summarize findings. Ask teams to explain their evidence and reasoning.

Step 8

Ask teams to consider what steps they would take next to reach a firm conclusion. What evidence would they collect?

Step 9

Collect all Investigative Report Forms.

Step 10
Activity 4: Reflecting on the Process of Scientific Inquiry
What the Teacher Does Procedure Reference

Explain that students will review the process used during their investigation. Ask,

  • “How did your investigation begin?”
  • “What testable question began your investigation?”
  • “As your investigation went along, did you ask other testable questions? What were they?”
  • “What evidence did you collect and analyze to answer your questions”
  • “Was all of the evidence you analyzed helpful in answering your question”
Steps 1–5

Explain that they will reexamine the evidence used in their investigation.

Step 6

Give each student one copy of Master 3.12, Analyzing Evidence. Give them 15 minutes to

  • consider the evidence they used,
  • write down what they learned from it, and
  • explain how it helped, or did not help, them to answer a question or choose between alternative explanations.
master iconStep 7

Ask for volunteers to share their answers with the class.

Step 8

Explain that in the next lesson, students will take charge of another investigation for the community health department.

Step 9
master icon= Involves copying a master.

print activity iconLesson 3 Organizer: Print Version
Activity 1: Unusual Absences
What the Teacher Does Procedure Reference

Explain to students that they will carry out a scientific investigation. They will be working as members of an investigative team from the local community health department.

Step 1

Divide the class into teams of three students. Explain that they will investigate a potential health problem.

Step 2

Give each student one copy of Master 3.1, Investigative Report Form.

master iconStep 3

Display a transparency of Master 3.2, Letter from Principal. Read it aloud.

transparency iconStep 4

Display a transparency of Master 3.3, First Memo from Director. Read it aloud.

transparency iconStep 5

Instruct teams to discuss testable questions that will help them in their investigation.

Step 6

Give each team one copy of Masters 3.4a–c, Attendance Data. Instruct teams to analyze data and record their findings.

master iconStep 7

Facilitate a class discussion. Focus on the following questions:

  • What is the reason for the higher number of absences among students in band class at Truman and Jackson middle schools?
  • If these absences are due to an illness, do band members from the two affected schools share the same symptoms?
  • Have band members from the two schools been in contact with each other?
Step 8
Activity 2: What’s the Cause?
What the Teacher Does Procedure Reference

Explain that teams will continue their investigations, focusing on the questions asked at the end of the previous activity.

Step 1

Give each student one copy of Master 3.1, Investigative Report Form. Instruct students to write down the testable questions asked during the last activity.

master iconStep 2

Display a transparency of Master 3.5, Second Memo from Director. Read it aloud.

transparency iconStep 3

Give each team one copy of Master 3.6, Interview Summary, and Masters 3.7a and b, Quotes from Interviews. Instruct teams to review the information.

master iconStep 4

Give each team one copy of Masters 3.8a–d, School Calendars. Instruct teams to compare the two calendars and write down their conclusions.

master iconSteps 5 and 6

Facilitate a class discussion. Focus on the following questions:

  • Is there a common reason for the absences of the band students at Truman and Jackson middle schools?
  • What are possible causes for the student illnesses?
  • How could students from both bands be exposed to a disease-causing organism at the same time?
  • Assuming that the students from the two bands are suffering from the same illness, when were they most likely exposed to the disease-causing organism?
Step 7
Activity 3: What’s the Source?
What the Teacher Does Procedure Reference

Explain that teams will continue their investigations, focusing on the questions asked at the end of the previous activity.

Step 1

Give each student one copy of Master 3.1, Investigative Report Form. Instruct students to write down the testable questions asked during the last activity.

master iconStep 2

Display a transparency of Master 3.9, Third Memo from Director. Read it aloud.

transparency iconStep 3

Give each team one copy of Masters 3.10a and b, Activity Tables, and Masters 3.11a and b, Activity Maps. Instruct teams to review the information and write down their conclusions.

master iconSteps 4–6

Facilitate a class discussion to summarize findings. Ask teams to explain their evidence and reasoning.

Step 7

Ask teams to consider what steps they would take next to reach a firm conclusion. What evidence would they collect?

Step 8

Collect all Investigative Report Forms.

Step 9
Activity 4: Reflecting on the Process of Scientific Inquiry
What the Teacher Does Procedure Reference

Explain that students will review the process used during their investigation. Ask,

  • “How did your investigation begin?”
  • “What testable question began your investigation?”
  • “As your investigation went along, did you ask other testable questions? What were they?”
  • “What evidence did you collect and analyze to answer your questions”
  • “Was all of the evidence you analyzed helpful in answering your question”
Steps 1–5

Explain that they will reexamine the evidence used in their investigation.

Step 6

Give each student one copy of Master 3.12, Analyzing Evidence. Give them 15 minutes to

  • consider the evidence they used,
  • write down what they learned from it, and
  • explain how it helped, or did not help, them to answer a question or choose between alternative explanations.
master iconStep 7

Ask for volunteers to share their answers with the class.

Step 8

Explain that in the next lesson, students will take charge of another investigation for the community health department.

Step 9
master icon= Involves copying a master.
transparency icon= Involves making a transparency.

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