Teaching Aerobic Cell Respiration Using the 5 Es

Abstract

Ask any group of high school biology teachers what topics their students find most difficult to comprehend and chances are that cell respiration will be among those mentioned. Such a situation presents quite a challenge to biology teachers since national science standards consistently cite information involving cell respiration among the key topics to be covered in high school biology courses. Knowledge of cell structure and the chemical reactions within the cell that provide a flow of energy are listed in Content Standard C of the National Science Education Standards (1996). There are many reasons why students find cell respiration difficult to understand. The abstract nature of the processes, the multitude of details, and a new technical vocabulary make the topic challenging to even the most diligent students. Over the years, I have tried many different approaches to teaching cell respiration, with varying degrees of success. Generally, these approaches involved some combination of lecture, demonstration, and laboratory activity; however the end results were always the same--mediocre test scores and a lack of enthusiasm among the students. Most recently, however, have adopted the 5E model of instruction and I have found it to be quite effective. Figure 1. Overview of the 5 Es. Engage--presents the topic in a way so as to excite the students. Explore--offers opportunities for the students to examine the topic. Explanation--provides students with further description of the topic. Elaborate--encourages the students to further investigate the topic. Evaluate--provides for a means to assess student learning. Unlike the traditional methods such as lecture, the 5E approach provides students with an opportunity to take more active role in their learning (Figure 1). Active-learning strategies like those used in the 5E method involve students in the types of inquiry-based learning called for by Content Standard A of the National Science Education Standards (1996). Since using the 5E method to teach cell respiration my students are more actively engaged in class and their test scores have improved. These findings are consistent with those reported by researchers who found that the use of the 5E method of instruction by biology teachers produced significantly higher grades than did the use of more traditional teaching methods. Furthermore, the researchers found that the students had a more positive attitude toward the study of biology (Lord, 1997; Allard & Barman, 1994). The 5E model is based on a constructivist view of education and consists of five phases: engagement, exploration, explanation, elaboration, and evaluation (Trowbridge, Bybee & Carlson Powell, 2004). The following describes the five components of the method. Taken together, they are designed to appeal to a number of different learning styles (Figure 1). Day 1: Engagement The purpose of the engagement phase of the 5E learning cycle is threefold: to introduce the lesson, to elicit interest and curiosity among the students, and to determine what they might already know about the phenomenon. When teaching cell respiration I try to engage the students by giving a demonstration in which I burn a large potato chip and use the energy released to raise the temperature of a small amount of water in a test tube. The setup for the demonstration involves the use of a ring stand, a clamp, and a test tube. A reconfigured paper clip is used to hold the potato chip and to anchor it to a cork base. Other food sources, such as an almond or a peanut, can also be used. I start the demonstration by asking the students how much energy there is in a single potato chip. After listening to their responses, I tell them that we are going to attempt to find the answer by burning a chip and measuring how much heat energy it releases. First, I give a student a thermometer and have that student measure the initial temperature of 20 ml of water that has been poured into a 25 x 200 mm test tube. …