Activity 3C Part 1: Measuring Obesity by Bioelectrical Impedance Analysis Human Electrochemical Cell Topic: Obesity Part of: Unit: Corpulosity: A Study of Obesity

Entire Activity Download (21 pages - 4.6 MB)

Individual Downloads

• Teacher Background Information (1 MB)
• Teacher Administrative Information
• Teacher Instructions for Using an Analog Multimeter-Answer Key
• Student Background Information (1 MB)
• Student Information Cards
• Student Data Pages

Keywords

electrochemical cell, electrode, electrical cell, electric current

Search Curricular Keywords

Key Concepts

electrochemical cell, electrolytes, electrodes, electrical conductivity

Process Skills Utilized

make a hypothesis, gathering data, organizing data in a chart form, analyzing data, draw conclusions, reading a scale on an instrument

Intended Grade Level - 6-8

Objectives

The students will be able to:

• Explain how an electrochemical cell works.
• Explain how a human can be part of an electrochemical cell.
• Determine which materials make the best electrodes in an electrical cell.
• Make observations and inferences; collect, graph, and analyze data.

Activity Description

Engage:
The teacher will hold up what looks like a ping-pong ball (the energy ball) and ask the class to decide if it can be made to light up just by holding it. The teacher will hold the ball by two fingers, making sure not to touch the two electrical contacts on the bottom. The teacher then touches the two electrodes on the bottom of the ball so it lights up. After students have seen the Energy Ball demonstration, place them into groups and give each group an Energy Ball. Students try to duplicate what the teacher has demonstrated and explain what happened and why.

Explore:
Students will learn how to use a multimeter as an ammeter to determine if their bodies have any electrical current associated with it.

Explain:
Students will become part of an electrochemical cell. By holding two different metals, one in each hand, and connecting these metals to a multimeter, the students will become part of a simple series circuit which will generate electrical current that can be measured in the microamps (μA) scale of a multimeter.

Activity Management Suggestions

This activity can be set up as a station or a number of different stations through which students rotate.

If materials are not readily available, you can set up a demonstration for your students.

Laminate the Student Information Cards for re-use.

For many groups to participate at the same time, enough pieces of pure metals should be provided so that each group can swap materials to test various combinations of metals.

If enough metal objects are obtained, students should be given an opportunity to use all possible combinations of metals.

An analog multimeter is used because it provides students an opportunity to incorporate math with science. Digital multimeters are difficult to read since the values often change as one is looking at the LED panel. This can be very confusing to a student. Students will be introduced to the multimeter and use it as an ammeter. The Radio Shack 18-Range analog Multimeter (Part #22-223) was used in the development and testing of this activity.

If you are using a different multimeter, you may be able to go online and find instructions to give your students in place of those included in this activity.

A simple handmade galvanometer can be made using bell wire and a compass. The handmade galvanometer will detect the presence of a current but will not give a quantifiable measurement on a change in the direction of flow.

Modifications

Pair students in need of extra assistance with other students and monitor closely to ensure that all participate fully in the activity.

.Students in need of extra assistance can be given specific tasks to do as appropriate.

Extensions

Students can investigate how the surface area of the metal plates changes the amount of current produced. Students can determine the area of the metal mathematically and measure the current. From their data, they can generate a ratio of current to square centimeter of area.

Students can bring different metallic objects from home to see if these objects can generate an electric current.

Students can investigate how alloys affect the amount of current produced.

Students can go on the Internet and research electrolytes in the human body.

Students can research the role of electricity in the human body. A suggested site might be Science News for Kids www.sciencenewsforkids.org. Go to the Human Body collection of articles and look up the Oct 1, 2003 article called “Spark of Life.” Page 3.

Research other areas as well to look at how scientists are trying to harvest the energy of glucose molecules.

References Used

Dawson, Trevor, Caputa, Krys, Stuchly, Maria,& Kravet, R. (2001). Electrical fields in the human resulting from 60-Hz contact currents. IEEE transactions on biomedical engineering. 48, No. 9, 1020-1026.

Sachem, FB, Werner, CD, Meyer-Waarden, K, & Dossel, O. (2000). Development of human body model for numerical calculation of electrical fields. Computer med imaging graphics, 24(3), 165-71.

Exploratorium Website:
http://www.exploratorium.edu/snacks/hand_battery.html

Science Museum:
http://www.sciencemuseum.org.uk/

Science News for Kids website:
http://www.sciencenewsforkids.org/articles/20031001/Feature1.asp

Spartech Software website:
http://www.spartechsoftware.com/reeko/Experiments/ExpHumanBattery.htm

Sydney Morning Herald:
http://www.smh.com.au/

top