Pickle Dissection by fjzhxb

VIEWS: 782 PAGES: 8

									Anthony G 399

11/17/2006

Pickle Dissection
Biological Concept: Anatomy of organisms, their habitats, and place in the food chain within that habitat.

Educational Concept: Observation, analytical thinking

Life Science Benchmarks: Organisms:    Understanding the characteristics, structure, and functions of an organism. Describe the function of organ systems Classify organs into the systems to which they belong.

Diversity/Interdependence:  Understand the relationships among living things and between living things and their environments  Describe the relationship between characteristics of specific habitats and the organisms that live there  Describe how adaptations help a species survive

Scientific Inquiry Benchmarks: Collecting and Presenting Data:   Conduct procedures to collect, organize, and display scientific data Collect, organize, and summarize the data from investigations.

Analyzing and Interpreting Results:   Analyze scientific information to develop and present conclusions Summarize, analyze, and interpret data from investigations

Transformation of Concepts: This lab stresses the importance of detailed note taking and sketches. Being diligent in accuracy is important in scientific research. Statistics are determined as to the length of the pickles. A discussion could be initiated as to what other areas a similar statistical analysis would be useful. The class could perform a statistical analysis on their heights. Classmates could measure each other and the data would be collected and analyzed. There should also be a discussion on pickles. A pickle is a pickled cucumber. The cucumber is washed, salted, and then placed in a brine solution for several weeks. Vinegar, sugar, and various spices are added to make the perfect pickle. A cucumber is a fruit, not a vegetable. Botanically speaking, anything that bears or is a seed is considered a fruit. Vegetables are any part of the plant that doesn't have to do with making new plants. The pickling process could also be discussed and provides a forum for a chemistry discussion. Vinegar is produced through a two-step fermentation process. It is

derived from naturally occurring sugars or starches and the taste differs depending on the source and affects the pickle’s taste as well. Starch is converted to sugar, which is then yeast fermented to make alcohol. The alcohol is exposed to acetobacteria, which in the presence of air converts it to vinegar. The vinegar also acts as a non-toxic preservative. A chemistry lesson could logically follow from this lab. Testing of the pH levels could be done on cucumbers and then pickles to introduce the concept of acids and bases.

Extensions: The process of dissection should be discussed in detail from where the animal comes from to what to do with it afterwards. The animal’s habitat should be discussed and it’s place within that habitat. The topics of interdependence and sustainability should naturally follow from this discussion. An ethical discussion of animal dissection could be addressed especially if the teacher is planning an alternative method of dissection like a computer simulation. Specific anatomical terminology is introduced. The terms ventral, dorsal, anterior, and posterior are to be labeled on the students’ drawings. In introducing those terms, they questions could be asked as to how these terms apply to various organisms.

Costs: 30 students will be working in pairs. One will be doing the cutting and the other will be making notes and drawings. Students can switch jobs if they wish. To make this an authentic demonstration, real dissection kits should be used. If the dissection kits are

unavailable or if an actual dissection is not planned, paper plates, straight pins, and classroom scissors could be used. These would cost less than $10. For economical reasons, an attempt should be made to obtain dissection supplies from the school or school district. If the resources are not available, it may be necessary to purchase dissection kits for the classroom. Disposable dissection trays are available for purchase but this cost would be incurred every year that this lesson was to be taught.

Initial setup, one-time costs: $272.45         Dissection trays - $97 (15 @ $6.46 each) Dissecting scissors - $23.25 (15 @ $1.55 each) Dissecting pins - $14.95 (box of 350 T-pins) Tweezers - $20.25 (15 @ $1.35 each) Scalpel with blade - $49.50 (15 @ $3.30 each) Safety goggles - $52.50 (30 @ $1.75 each) Rulers - $7.50 (15 @ $0.50 each) Six foot measuring strips - $7.50 (optional, 15 @ $0.50 each)

Consumable supplies: $10.50    30 sheets of graph paper - $ 1.50 1 large jar of large pickles - $4 Vinyl gloves - $5.00

Time required:    Developing lab: making copies, gathering supplies – 30 minutes Prepping lab: setting out supplies – 5 minutes Activity: students getting their set-ups and pickles, performing dissections, gathering data, statistical analysis, measuring student heights (time permitting) – 1 hour  Cleanup: wash trays, dispose of pickles, wash hands – 10 minutes

The first time this lab is performed, it will take a bit longer than in subsequent years. Besides the fact that the teacher will be more experienced and likely to set up faster, the dissection supplies will be stored and ready to use. The initial preparation might be an extra hour.

The Lab: Yes, the students are only dissecting a pickle but the point of this lab is to learn the procedure and we attempting to provide an authentic simulation. The lab is about dissections, not pickles, although there are lessons to be learned about fruits and vegetables. Ideally, they will be using real dissection tools but perhaps not scalpels, as scissors are dangerous enough in the hands of elementary students. Actual dissection trays should be used to provide authenticity especially if an actual dissection is planned. These supplies would be necessary for that lab anyway.

A short lecture should precede the lab. Students are preparing for a dissection and this pickle is their practice. Depending on the animal(s) to be used (in actuality or in a simulation), that animal’s habitat and place in the food chain should be discussed. As they dissect the pickle, they should be drawing correlations as to what will be different and similar to this exercise. The lab is also designed to teach students to keep accurate records and make detailed sketches. A statistical analysis will also be made regarding pickle length with the data collected by the class. Students collect their supplies. They gather their dissection tray, pins, scissors or scalpel, graph paper, ruler, goggles, and gloves. Then the teacher passes out the pickles into the students’ trays while they put on their gloves and goggles. Students will examine and sketch the pickle, noting shape and texture. They make notes and label the anterior (front, which is the end of the pickle with the stem), posterior (rear), dorsal (back), and ventral (underside). The pickle is lying on its “back” as students are going to cut open its “belly”. Any recognizable characteristics should be noted. Then measure the pickle and note its length in centimeters. Pin the pickle to the tray at the anterior and posterior ends. Now it’s time to make an incision about halfway through the pickle from the anterior end to the posterior end while being careful not to cut the pickle in half. Two more incisions are made about 2 – 5 cm from each end. Then open up the pickle and pin the flaps back to the tray. Another sketch is then made and all labels are placed on the sketch. The drawings should be of similar size. Using a dissecting probe, the seeds are now carefully removed while being careful not to remove any flesh. The seeds are placed on the tray and the drawing and notes

should reflect this. Students should be thinking about what they will be looking at in an animal dissection and the similarities and differences in this exercise. They should think about the organs and organ systems they will see in an animal. The relationship between those animals, their habitats, and the food chain in that habitat should be discussed in each group and as a class.

Students can move around and look at other pickles noting any similarities and differences. At this time, one person from each team writes their pickle’s length in centimeters on the board. After all 15 lengths are recorded, the teacher can plug these numbers into a scientific calculator or computer to make a statistical pickle analysis. A chart drawn on the board will be filled in:

N

Max

Min

Range

Sum ge

Avera n

Media

These terms will all be explained and then another analysis could be performed. Students measure each other’s height in centimeters and perform the same type of analysis on another chart drawn on the board.

Assessment: What safety procedures are used in dissections?

Can the instruments used be dangerous if used improperly? Why is it important to record data and make accurate sketches? What do the statistical numbers mean and how are they useful? If the pickle were an animal, what would be the function of the exterior surface? What organs and organ systems would be inside? Why is the pickle considered a fruit and not a vegetable? If this were a frog, what would its habitat be? A rat? A fish? What other organisms would live in these habitats? Draw a food chain of which one of these animals is a part. Where would you fit into this food chain? If this animal were to go extinct, what would happen to the food chain? Would you be opposed to dissecting an actual animal? Why or why not? What did you learn in this lab? What questions do you have about dissection?


								
To top