Academic journal article The Science Teacher

The Inquiry Flame: Scaffolding for Scientific Inquiry through Experimental Design

Academic journal article The Science Teacher

The Inquiry Flame: Scaffolding for Scientific Inquiry through Experimental Design

Article excerpt

[ILLUSTRATION OMITTED]

The National Science Education Standards define scientific inquiry as

"the diverse ways in which scientists study the natural world and propose explanations based on the evidence derived from their work. Scientific inquiry also refers to the activities through which students develop knowledge and understanding of scientific ideas, as well as an understanding of how scientists study the natural world" (NRC 1996, p. 23).

In the lesson presented in this article, students learn to organize their thinking and design their own inquiry experiments through careful observation of an object, situation, or event. They then conduct these experiments and report their findings in a lab report, poster, trifold board, slide, or video that follows the typical format of the scientific community studying the natural world. This article presents a scaffolded approach to inquiry and illustrates its use in the classroom.

Background

The candle and jar demonstration (ABC Science Online 2005; Hodgkin 1995) is often used in elementary or middle school science classrooms, but secondary teachers might find it helpful as a diagnostic exercise that scaffolds students' experimental procedures. In this article, the classic demonstration is reworked to lead students to design and conduct experiments of their own.

Before using the candle and jar activity in the classroom, teachers should be familiar with common student misconceptions and the scientific principles associated with states of matter, conservation of matter, energy transformations, chemical reactions (e.g., combustion), kinetic molecular theory, and atmospheric pressure and composition.

The demonstration

To begin the lesson, the teacher presents the class with a discrepant event in the form of a lab demonstration. Students are told to focus their attention on making observations. Statements such as "use your senses carefully, as each of you will need to repeat this" or "observe how this behaves because I am going to ask you to make it behave differently" can help students focus. Then the demonstration commences:

The teacher holds a glass jar above a burning candle. The candle is positioned between two metal rods in the bottom of a shallow glass pan containing clear liquid (see photo, opposite). The liquid in the pan is high enough to cover the metal rods. The teacher holds the jar above the candle and asks students to come close enough to make careful observations. (Safety note: Both students and the teacher need to wear eye protection [i.e., indirectly vented chemical-splash goggles] during this demonstration.)

The teacher waits for students to settle and then explains that she is about to lower the jar over the candle and place it on the metal rods--so that the mouth of the jar is below the surface of the liquid, but rests on top of the rods. A space remains between the bottom of the pan and the lip of the jar.

The teacher then slowly lowers the jar over the candle and watches her students' faces as the candle is extinguished and the liquid level rises in the jar (see photo below). (For an explanation of why the flame is extinguished, see "How does it work?" p. 49.)

Step 1: Careful observation

After the demonstration, students return to their seats to think for a few moments about what they have seen or share observations with a partner or small group. The teacher circulates as students write down their observations, or behavior descriptors, on yellow sticky notes (one observation per note) to place on the Observations Starbust Diagram (Figure 1, p. 46). If this is the first time students have used the diagram, they may be reluctant to start. This scenario describes what might happen next:

The teacher then leads a whole-class discussion, inviting students to offer their observations as she records them on large yellow sticky notes and places them on a poster-size version of the Observations Starburst Diagram (Figure 1). …

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