Wendy Decter, M.D.
Students will develop their own scientific investigations into the cause of death in the form of soliciting information from the coroner and examining evidence in ways they have previously learned in forensics class. They will have to decide what questions to ask the coroner and how to use the information they receive.
Students will be given a detailed scenario of a possible crime scene. Physical "evidence" taken from the scene will be supplied, such as fibers, hairs, possible "blood" stains, found objects, along with sketches and measurements. A man is found dead at home, but so far the "coroner" can only say that the cause of death is cardiac arrest. But the plot will thicken. The teacher plays the role of the coroner, giving out only bits of information, which will drive the details of further investigation. Through directed discussion, the "coroner" discovers that her CSI's need to know what goes right in the cardiovascular system before they can determine what went wrong.
The first lessons are devoted to learning about the anatomy of the cardiovascular system. Several types of media will be employed. There are many excellent videos and interactive websites illustrating the structure and function of the cardiovascular system. Students will explore these as a group and individually. Students will conduct independent research centered on specific questions and then produce a large schematic drawing of the anatomy of the heart and the path of blood circulation. This schematic will be used over the course of the unit. As the "coroner" releases more information from the "autopsy" the students will focus on particular areas of the anatomical schematic that have been disrupted and predict the functional outcomes leading up to the "victim's" cardiac arrest.
After establishing a basic knowledge of the anatomy we will trace the path of blood by playing "The Heart Game". Each student becomes a part of the heart (atria, ventricles, valves), the aorta, the vena cavae, the right and left lung, the brain and the feet. All other students become oxygenated or deoxygenated blood cells. Students wear signs with their "parts" drawn and labeled. "Circulating" red blood cells carry red or blue cardboard "cells" to indicate whether or not they are "oxygenated". It is the job of the "heart" to direct the flow of blood correctly. The "lungs" must exchange the blue cells for red cells. The "brain" and "feet" must use the oxygen and exchange the "red" cells for "blue" cells. This is performed "at rest" and then while "exercising". All the while the "valves" are calling out "lub" and "dub" at the right time. It's very interesting to see if the heart can keep up with the demand for oxygen! Roles are traded so that all students get to "circulate" and be part of the heart.
Subsequent lessons deal with the maintenance of blood pressure, the role of the coronary arteries, and the pacemakers of the heart, and oxygen exchange.
Students will construct a large poster of their biomechanical models of the cardiovascular system within a specific rubric. They will use their biomechanical schematics to predict the results of interruption in various areas of their models. They can start to form their hypotheses of how the cardiac arrest occurred or continue to question the coroner. As the coroner supplies more information the specific cause of the cardiac arrest will become clear. Students will have to decide if a crime was committed. They will then tackle the final project, a persuasive essay and presentation to the jury, defending their argument as to what happened, with facts and evidence.
I have designed this unit to take into account different learning styles and different abilities. The "Heart Game" is directed at tactile-kinesthetic learners in particular. The game can be played both at the beginning and end of the unit so that students can see how they have mastered the subject matter as their travels as blood cells become much smoother. This game can be modified for students of any grade by making the path of the blood cells more or less complex. The "blood cells" can travel only through the left and right sides of the heart and through the lungs for a simpler route for younger students or it can travel through the atria, ventricles, valves, to the brain, lungs, kidneys and feet, or other organs for a more complex route.
Students who have difficulty with writing or verbal expression have the opportunity to demonstrate their knowledge by creating the schematic drawing. Reading and writing in the sciences are extremely important and I have included practice in the form of a persuasive essay. Presentation skills are also practiced in this unit.