Investigating Variables : Passengers Supported by Lifeboats

Peggy Greenwaldt
Cyrus Elementary School
Cyrus, MN
Based on an original activity from the FOSS Variables Module, Investigation 2: Lifeboats, pages 1- 13.
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Students participate in a guided inquiry, lab investigation by constructing a fleet of boats and discover how many passengers (pennies) each will hold before sinking. The variables of material used to construct boat, boat depth and arrangement of passengers are explored. Some of the most important scientific concepts students learn are the result of their ability to see relationships between objects and events. Relationships always involve interactions, dependencies, and cause and effect.

While conducting the Lifeboats inquiry lesson the students will:
- Identify variables that might affect the number of passengers (pennies) their boat can hold without sinking.
- Measure the capacity of boats in metric units.
- Conduct controlled experiments.
- Graph the results of experiments and use the graph to make predictions.
- Relate the capacity (displacement) of a boat to the number of passengers it can hold.
- Use scientific thinking processes to conduct investigations and build explanations: observing, communicating, comparing, organizing, and relating.

Learning Goals

Learning Goals:
Science as Inquiry:
Develop students' ability to do and understand scientific inquiry.

- Identify questions; design and conduct a scientific investigation to answer those questions.
- Employ tools to gather, analyze, and interpret data.
- Use data to construct reasonable explanations.
- Develop and communicate explanations using evidence.
- Recognize and analyze alternative explanations and predictions.
- Use mathematics in scientific inquiry.
- Understand that scientists use different kinds of investigations and tools to develop explanations using evidence and knowledge.

Content: Physical Science
Develop students' understanding of motion and forces.
- The motion of an object can be described by its position, direction of motion, and speed. That motion can be measured and represented on a graph.

Science and Technology
Develop students' understandings about science and technology.

- Scientists work collaboratively in teams and use tools and scientific techniques to make better observations.
- Many different people in different cultures have made and continue to make contributions to science and technology.

History of Science
Develop an understanding of science as human endeavor.

- The work of science relies on basic human qualities such as reasoning, insight, energy, skill and creativity - as well as on scientific habits of mind, such as intellectual honesty, tolerance of ambiguity, skepticism, and openness to new ideas.

Scientific Concepts
- A variable is anything that you can change in an experiment that might affect the outcome.
- Capacity is the maximum volume of fluid a container can hold.
- In a controlled experiment, all the variables are controlled expect one, allowing the experimenter to observe the effect of that one variable on the outcome.
- A two-coordinate graph displays the relationship between the independent and dependent variables in an experiment.
- The larger the capacity of a boat, the greater the number of passengers it can hold.

Context for Use

Investigating lifeboats is appropriate for grade 5 and 6 students. Class size depends on the amount of materials available. (FOSS modules are organized for 32 students working in 8 collaborative groups of 4 students).
This experiment is an inquire lab experiment that should last 2 sessions of 40 to 60 minutes each for the students' planned experiment.

Skills and concepts that students should have already mastered before encountering this activity include:
  • Raising questions of the natural world.
  • Seeking answers to questions by making careful observations.
  • Willingness to try things out.
  • Some things change so slowly/quickly they may be hard to notice.

Special Equipment:
Equipment needed is determined by the experiment students design. Possible ideas for creating an inquiry science experiment may include different sizes of boats of the same material, boats of different material that are the same size, different kinds of safe liquids to float the boats in, and measuring the displacement volume.

Equipment listed in the FOSS Variables Module
6 paper cups
1 sponge
2 books
1 pencil
1 permanent marking pen
2 scissors
50 pennies
1 meter tape
2 plastic cups
1 syringe, 50 ml
1 Graduated cylinder, 50 ml
1 basin
Variables Journal
Paper towels

*Students may need to bring materials from home for the inquiry investigations.

Description and Teaching Materials

Students will complete Part 1: Exploring Boats as planned in the FOSS Variables Module, Investigation 2: Lifeboats.

This is a brief overview of Part 1.
1. Introduce the Lifeboats
2. Preview Boat Building
3. Construct Two Standard 3-CM Lifeboats
4. Introduce Passengers
5. Return the Basins and Pennies
6. Identify Variables
7. Find the Capacity of the 3-CM Lifeboats
8. Compare Capacities
9. Clean up

Students will create an inquiry investigation about boats and present data findings to the class.

1. Ask students to take out their science journal and write a list of variables that might affect the number of passengers supported by a boat. Student lists might include these variables among others:
  • Boats of different size (Capacity)
  • Distribution of passengers
  • Gentle versus reckless placement of passengers
  • Conditions of the sea
  • Material used to build the boat
  • Kind of liquid boat is floating in
2. Ask students to write questions they have about boats.

3. Students share their questions with the class.

4. Ask students to write questions about boat capacity. Scientific questions address the natural world (objects, organisms, events).

5. Students share their questions with the class.

6. Have students use the numbers 1, 2 and 3 to represent the question they are most interested in finding the answer to, number 1 being the most interesting to them.

7. Have students share their question that they numbered 1 and list these on a large sheet of paper. Discuss how different questions lead to different kinds of investigations (observation, collection, experimentation).

8. Pair students according to the questions they would like to investigate (2 or 3 per group). There can be more than one group investigating the same question as each group will probably use a different type of investigation. Students should be assigned rolls: Getter, Starter and Reporter as suggested in the FOSS Variables Module.

9. Discuss how the key skill in designing an investigation is the ability to predict the relationship between what you want to know and what you are measuring.

10. Student groups develop an investigative question that can be tested.

11. Students plan their inquiry investigation about boats by writing/drawing about the following elements that are checked/approved by the teacher before engaging in the investigation:

A. Investigative question
B. Description of experimental method
C. Materials needed (Students will be using the same tub to put liquid in as in previous lessons in the FOSS Module. Boats need to fit in the tub.)
D. How students are going to organized data (graph, table, picture, etc.)

12. Allow plenty of time for the students to conduct their investigation. Students may need to bring materials from home.

13. Check group progress as they work. Make sure they are following the experimental method they had decided on and are recording data in an organized way. (Students may want to change what they are doing if they are not seeing the result they expected. Students need to continue with the experiment as planned as this is part of the scientific learning process and this may lead to further questions.)

14. Groups need to create a Boat Investigation Poster. The following elements should be included on the poster.

A. Investigative question.
B. Description of experimental methods.
C. Organized data (graph, table, picture, etc.)
D. Conclusion based on analysis and interpretation of data and evidence.
E. Further questions and suggestions for next experiments.
F. Reflection on experimental design and methods, suggested improvements.
G. Names of investigators and date.

15. Poster Sharing Session: 40 minutes
Groups display posters around the room.
Group partners need to decide which partner will stay by the poster for the first and second 20 minute time period. One person will stay by the poster and the other will travel to the other posters.
The group member staying by their poster for 20 minutes will answer questions, give explanations, ect., to the other group members traveling to the posters.

16. Ask students to respond to the following questions in their science journals.

1. What was the best part of this inquiry investigation?
2. What results surprise you?
3. What questions do you still have about boats?
4. What other group's investigation was most interesting to you and why?

Teaching Notes and Tips

Teaching Notes
A possible issue or concern may be that students may not have the skills to formulate an investigative inquiry question. This activity is different from the original FOSS Variables Module lesson as that lesson is teacher directed and students do not come up with their own inquiry question to investigate.


Students will be assessed by their participation, poster session, journal entries and their ability to answer questions during the poster session.


Standards Match
5.I.A.2 clear communication of methods

5.I.B.1 perform a controlled experiment

5.I.B.2 observe scientific investigation