Form and Function in the Marine Environment
Type of Activity:
- Inquiry lab
- Authentic Assessment
This lab exercise is designed for environmental studies in life science and biology. The audience could be anywhere from grade 5 - 12 depending on the complexity of the level achieved.
This activity is used to demonstrate and reinforce the concept that "form follows function" in the natural world. This lesson happens to deal with the marine environment but this format could be adapted and used for terrestrial organisms, systems of the body, or the study of plants. The question the students answer is "How does the function of an organism's movement dictate what forms will develop to assist it?" A preliminary discussion of lift and drag is necessary, to give the students the background needed for levels two, three, and four. This activity is multilevel and therefore can be modified to fit the equipment needs and the grade level of your students. Each level is outlined.
This activity demonstrates the relationship of form and function in the marine environment. Since the lab is a progressive set of activities, the teacher can select appropriate activities which fit available equipment and background.
- Soft modeling clay
- Colored fluid
- Computer with HyperCard capability
At this level the students select their partners, usually pairs or threes but this can be modified according to the amount of equipment available. The students pick the shapes of that marine organism they want to use. Dive magazines, periodicals the deal with marine environments, and videotapes help the students get an idea of what they might like to work with. Once the students have selected an organism, they must identify all the body design forms they think will have a bearing on inducing lift or drag in the organism. Once this part is done, they make soft clay models of the shapes that they are going to test in level two. Don't use a clay that needs to be fired because the students will want to be able to modify their shapes. This part of the exercise takes about one class period but could take a little longer depending on the age of the students.
Level Two -
In this level the students test the shapes and models they have constructed. To do this they need a 5-10 gallon aquarium filled about two thirds full of water. They also need a 30 cc syringe without the needle. Old syringes can usually be acquired at a veterinarian's office. The students also need some type of colored water which they will draw into the syringe. If the colored water has some sugar in it and is warmed a little, it will shimmer and give a better idea of currents when the students shoot it at their models. One student needs to hold the model in the aquarium with something like a drink straw and the other needs to run the syringe. Count on the fact that they will probably need to practice a bit. A light shining on the back of the aquarium will help students spot the currents better. The students should map any currents that they can identify on any shapes that they have selected. It is a good idea to change the shape or the angle of the shape as they shoot the water at the shape. Some examples of shapes are tails, fins, flukes, general body tube shapes, and the shape of the head. This level may take one or two periods depending on the number of groups and the number of aquaria and syringes that are available. It is a good idea to try to have at least half the number of aquaria as there are groups.
Level Three -
This is a simulation using the computer and an application called HyperCard. This application allows students to draw and manipulate what they draw in an animated format. It is possible to add sound to the stacks although this requires a lot of memory if they are saving the HyperCard stacks on high density disks. Sound stacks work best if the students can save on the hard drive.
It takes about 2-3 hours to teach students how to do the HyperCard application well enough so they can proceed with their own creations. It takes another two to three class periods for them to actually make their stacks. If this application is used repeatedly, the students become very adept at its use and can make a stack in two class periods easily. There are a couple of presentation and assessment options once students have completed their stacks. One option is have the students plug their computers into a monitor or big screen projector and present their stacks as an oral assignment. This is a great opportunity for authentic assessment. Another is have them turn their disks in for assessment.
Level Four -
This level also utilizes authentic assessment but in this session the students are not using the computer to build their models but, instead are actually constructing models that they build themselves or they can use themselves as the model. The swimming pool is a good place for this part of the lab exercise. One part of this level that is very important is the experimental design segment. This portion requires a lot of student creativity or it may require a lot of teacher direction. This part may be required or it may be an enrichment activity. If this level is required, it takes more teacher direction. If used as an enrichment activity there could be low student participation but the students proceed completely on their own. A suggestion of using leg kicks off the side of the pool is usually all that is needed to get the students thinking but good experimental design with controls and repeated trials should be a big part of the lab design. The students could also design a model of the marine animal if they can find some way to propel it through the water. This level is very open-ended and really can stimulate some creative ideas from the students.
Assessment of the first two levels is pretty wide open to the whims of the individual teacher. One option is to attach point totals to the successful completion of each level or attach a letter grade to each level in a contract grading situation. For the level three HyperCard evaluation I've used a continuum where a one is below average, two is average and three is above average of selected categories such as technical accuracy, quality of presentation and creativity or uniqueness of the idea. Another approach is have the students assist in the evaluation. The high score and the low score are eliminated and an average of the rest of the scores become their grade for the presentation.
The level four presentation is not only a demonstration of the student's model but it is also a demonstration of their ability to design and carry out an original lab design. This part of the lab exercise requires the highest order thought but it also provides an excellent opportunity to implement the process portion of the NRC Science Standards into the classroom.