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Akron Global Polymer Academy Lesson Plans

Where did the Water Go? An Investigation in Scientific Methods

Grades: Grades 6-8
Author: Dr. Kathie Owens
Source: Inspired by an activity presented by Jon Valesek, Mississippi School for Mathematics and Science

Abstract

As a result of the teacher-conducted discrepant event demonstration (described below), students will pose a problem. They will formulate their hypotheses, conduct experiments, and report their findings. Since it is unlikely that the students will be able to reproduce the outcome of the teachers' demonstration, it will be pointed out to them that very often scientific investigations do not lead to "answers".

Objectives

What should students know as a result of this lesson?

What should the students be able to do as a result of this lesson?

Materials

Procedures

Engagement

The teacher will conduct the following demonstration:

  1. Out of sight of the students, put about a teaspoon of sodium polyacrylate in the bottom of one of three identical opaque cups.
  2. Tell students that you will be testing their powers of observations with an activity. The activity will be a variation of the "old shell game".
  3. Put the cups in plain sight of the students. Tell them that the cups are identical and "empty". Do not let the students look inside any of the cups.
  4. Pour about 1/4 cup of water in one of the cups without the sodium polyacrylate. While students are observing, switch the positions of the cups on the table. After several shifts, poll the students as to the location of the cup with the water in it.
  5. When students have guessed the water-cup, pour the water into the other cup without the sodium polyacrylate. While students are observing, switch the positions of the cups on the table. After several shifts, poll the students as to the location of the cup with the water in it.
  6. Pour the water into the cup with the sodium polyacrylate; switch cups around; poll the class. When you turn the cup that had both the water and the sodium polyacrylate (a polymer) upside down, no water will come out.
  7. Students will probably exclaim, "Where did the water go?" This question is the students' testable question for the next part of the lesson.
  8. Be sure to review what makes a test a "fair test" before proceeding.

Assessment: Make sure students are observing the demonstration. Monitor the students' responses throughout this part of the lesson. Make sure the students recognize that their response to the demonstration is their testable question.

Exploration

Have available a variety of absorbent materials (cotton, paper towels, cloth pieces, etc.) and cups identical to those used by the teacher. Before any group experiments to answer its question, have the group write down its hypothesis and the series of steps it plans to follow. Students conduct their experiments, collect and organize their data, and formulate their conclusions.

Assessment: Be sure students are proceeding safely and following authentic scientific procedures.

Explanation

Students report their findings and answer the posed question. After all reports have been shared with the class AND no group has been able to reproduce the outcome of the teacher's demonstration, the teacher discusses the reality that sometimes "nothing happens" as a result of scientific studies. "No findings" IS a finding! Sometimes scientists work for many years to show "proof" of their hypotheses, but are unable to "prove" what they seek. Emphasize the nature of scientific investigations. Remind students that they use scientific methods daily to solve everyday problems, like deciding what to wear to school.

Assessment: Have students summarize their understanding of the methods of science investigation and the nature of science as an endeavor. In their own words, students will describe terms related to scientific methods: data, hypothesis, experiment, and findings.

Elaboration

Hold a class discussion focused on the nature of science investigation by telling the stories of famous scientific discoveries. For examples: using analyses of mathematical calculations, Neptune was predicted before it was actually observed. Post-it notes are the by-products of a scientist's quest to make super-glue that did not measure up to standards. Well-known and long-held theories (like the geocentric solar system) are abandoned when contrary evidence is obtained. Students could research significant discoveries in science and summarize the methods used to bring about the findings.

Assessment: Ask students to discuss their perceptions of the nature of scientific investigative methods at the close of this discussion.

Prerequisites

Misconceptions: Students may assume that the result of every science experiment results in "an answer".

Best Teaching Practices

Alignment with Standards

NGSS Standards:

Common Core Standards:

National Standards:

Ohio Standards:

Content Knowledge