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Biology: More Lab Ideas

Excerpts from AP Biology Teachers Discussion Group

Diversity Lab Suggestion: "I did the exercise with just animals. In my AP class we ignore fungi and protists, and only spend about 1.5 days on bacteria/viruses. We have just finished a lengthy plant unit. Basically, what I did was cut out about 20-25 pictures of animals from biological catalogs and wildlife magazines trying to get as many phyla as I could. I glued them on posterboard and numbered them. (I will laminate the boards.) The animals go from sponges up through mammals. I couldn't find some organisms I really wanted, like monotremes, and had trouble finding marsupials. (I threw in a few really tough ones like onychophoran, which is a sort of segmented worm with legs and in its own phylum.)

I asked students to: (1) Classify the organisms as completely as possible. Basically, they are getting to the class level with most, and further with some. They are using the appendix in our text (Starr and Taggart) to do this, as well as the chapters in their book and the other books I have. (2) Make a chart or checklist where they decide what characteristics to include for their set of animals. They are using wordprocessing programs to do both of these tasks. I had planned for them to make up 10 questions on their chart as well, but I have a feeling that that is too much to ask in three periods. As I said, I never expected this exercise to generate such intense interest!

In terms of what we'd covered in class before doing this: We had covered through arthropods. The echinoderms and chordates will be covered next week, after they finish the exercise. However, reading of both chapters was assigned before we started. The students have a pretty good classification background, as we use the Green Version Biology, which has an excellent coverage of classification and characteristics for both animals and plants, which we cover in first-year biology."
-- Anne Soos, Stuart Country Day School, Princeton, New Jersey. 2/28/99

Additional Lab Suggestion: "I use the pH buffer capsules to make up buffer solutions at 2, 4, 6, 7, 8, and 10 and let my students design their own labs. These capsules are available from Carolina Bio. I also have my students think about the pH of the soil, rain, and maybe from standing water outside somewhere if there is any. "
-- Franklin M. Bell, St. Mary's Hall, San Antonio, Texas. 3/8/99

Question: "I need help locating the little capsule animals that dissolve when put in water and the little sponge creature is left. I use these for several scientific method labs at the beginning of the year. Nobody carries these little things around here. Any ideas?"

Answer: "Try the following:
  • A store like Spencer Gifts, or a five-and-dime store
  • Order from Instant Products, Inc., 4804 Strawberry Lane, Louisville, Kentucky 40214; telephone: (800) 862-6688
  • Wal-Mart's checkout counters
  • Some science supply houses: try Carolina, Science Kit, Cenco, and Fisher
  • Walgreen's Drug store (usually dinosaurs are in them)
  • CVS drug store with toys ($1.98 for 12)
  • The card/gift stores in your area (Hallmark, etc.)
  • MJ Designs (a large craft store-chain on the East coast); Michaels may also carry them
  • A Nature Company store or catalogue."
Question: "Can you grow N-fixing bacteria?"

Answer 1: "Check a standard microbiology lab for exercises on soil microbiology. To grow them requires a synthetic medium (every ingredient known and measured as opposed to nutrient agar); they are a bear to prepare. If you can grow them, use negative staining (India ink) for an interesting effect. I haven't done this in a long, long time but if you have any difficulties, contact me and I will look through my materials from the time when I taught microbiology in the Alhambra City High School District."
-- Stuart D. Schnell, John C. Fremont High School, Los Angeles, California. 10/21/99.

Answer 2: "If you have good microscopes (preferably darkfield) you can see them easily by taking a nodule off a legume plant root and crushing it with a small amount of distilled water. You should see them under 400X. I've used any available legume family plant, such as clover or beans."
-- Bruce Faitsch, Guilford High School, Guilford, Connecticut. 10/22/99

Question: "Any advice regarding planaria labs?"

Answer 1: "We used to have our freshmen and sophomores do science fair experiments, and we always had a few work with planaria. Yes, they do regenerate; it takes about 3-4 weeks (if I remember correctly, it was a few years ago). Both halves, if each survives, will regenerate. It is best to put them on a piece of Saran Wrap, which is placed on ice to anesthetize them; then, using a sterile scalpel, slice them in half. Feed them well before slicing them, then don't feed them again until they've regrown."
-- Bonnie Polan, Beverly High School, Beverly, Massachusetts. 11/5/99

Answer 2: "I have often done regeneration experiments with planaria in my general biology classes. I can usually catch planaria by tying a piece of raw liver to the end of a string and hanging it in a pond near some rocks for a few hours. I usually catch quite a few. I bring in a big bucket of pond water so the kids can change the water every other day in their regeneration experiments.

I found this protocol in an old biology manual. You can anesthetize planaria using Epsom salt crystals. I think it works better than ice. Place the worm in a watch glass and add Epsom salt crystals, a few at a time, with a forceps until the worm is 'out.' It is fairly easy to get creative cuts this way. The students have cut four-headed worms that have regenerated very well. When the experiments are over, I put all of the regenerated worms back into my stream. I have been teaching biology for 21 years, so you can imagine the number of strange looking planaria that are in my stream. Every year I catch some weird ones!"
-- Sande Ivey, Bangor Area Senior High School, Bangor, Pennsylvania. 11/5/99

Answer 3: "Check the classic, Animal Without Backbones, for good information. There is an anterior-posterior gradient. If you cut off the head, you can get a two-headed monster. If you cut the tail, you will get a stump. If you cut it lengthwise, you will get two. Similarly, if you cut if in half (crosswise) right in the center, you will also get two. I plan to do this with my AP class and perhaps my honors after the AP Exam. Be certain to use deionized water."
-- Stuart D. Schnell, John C. Fremont High School, Los Angeles, California. 11/5/99

Question: "Does anyone have any suggested lab activities that students can do when investigating cancer? When we do independent research projects, students always want to explore cancer."

Answer: "CellServ has several excellent and inexpensive kits that I highly recommend:
  1. Visualization of normal and transformed cells; looking at cells grown in culture
  2. Heterokarya and cell fusion
  3. Cytotoxins and cells; looks at in vitro technology and cell aberrations of mouse fibroblasts
  4. Human chromosome spreads: using chromosome splats to look at aneuploidy
I used kits (1) and (4) last year with great success. My students found cancer cells in kit #1, and saw how karyotypes can be prepared in kit #4. Both were really easy and worked well. With kit #4, my students were able to find and count chromosomes in human cells and find cells with extra chromosomes. Really nice!

I took this information from an old order form, but believe it is still current: CellServ CATCMB/103 McCort-Ward Bldg., Catholic Univ. of America, Washington, DC 20064. Tel. (202) 319-5725."
-- Franklin M. Bell, St. Mary's Hall, San Antonio, Texas. 12/16/99

Question: "Can anyone help me with a lab protocol? Soak a frog in some solution for several weeks -- the frog becomes transparent, then you inject dyes into the veins, organs, etc., to stain the systems different colors. Does this sound familiar to anyone?"

Answer: "The most widely used techniques of this sort involve staining bone and cartilage rather than veins and organs. Skeletal stain preps are fairly easy to do, but require that the specimen first be hardened for several weeks in 10 percent formalin, so that may be a stumbling block for classroom use. Then the specimen is 'cleared' (made transparent) by soaking for several days in 4 percent potassium hydroxide (caustic solution, possibly another classroom hazard). Then a solution of alizarin red dye in acetic acid is added. This stains the bone (calcified tissue) a deep red. If you are doing cartilage, additional stains (such as methylene blue) will be needed. Staining of veins, organs, etc. usually requires perfusion with latex solutions, etc. This may be beyond the ability of most students just because it is tedious and requires some special equipment.

But before you can even begin all this, you must have a specimen. I was under the impression that science fair rules now prohibited the sacrifice of vertebrates. Can anyone clarify this?? One possible way to obtain a specimen is to ask a local veterinarian to save dog/cat fetuses removed during neutering/spaying procedures. But I'm not certain that even that is legal under science fair rules.

References for the bone/cartilage stain procedures:

Russell, E. L. "Improved Methods for Staining Bones of Small Fetuses and Vertebrates in Alizarin Red." Bioscience 23 (1973): 366-367. Schwartz, L.M. "Vertebrate Skeletal Preparations, A Manual." American Biology Teacher (January 1977): 35-41."
-- C.O. Patterson, Texas A&M University, College Station, Texas. 2/29/00

Question: "Does anyone know how to care for leeches?"

Answer: "I've kept leeches alive for months in the refrigerator in a finger bowl with spring water. I cover them with another finger bowl to minimize evaporation. If you keep them cold, they don't need to be fed very much, if at all. Also, bacteria do not build up. Then take them out as needed. I keep all sorts of things like that in my refrigerator. Protozoan cultures, for example, can be maintained quite a long time at refrigerator temperature, as can frogs. The Board of Health is appeased because we keep food for human consumption out of there (at least, I tell my colleagues to do that)."
-- Barbara Beitch, Hamden Hall Country Day School, Hamden, Connecticut. 3/12/00

Question: "Is there a good version of a surface area versus volume exercise?"

Answer 1: "I just revised the BSCS Blue Version investigation on the effects of cell size on the efficiency of exchange of materials by way of diffusion (Inv. 6B, for those of you who teach the seventh edition). I think that it works much better the way I've changed it, and my students worked through it quite nicely last week. I may even try it with my next year's AP class when we get to that topic. Basically, the procedure described in BSCS is to make three agar cubes, 1 cm, 2 cm, and 3 cm. When the molten agar cools (use 3 percent concentration), and before it solidifies, add phenolphthalein powder to bring it to a final concentration of, I think, 1 percent. Stir thoroughly. (For anyone interested in trying this, I shall give exact concentration of the agar and also recommended amount to make for about 20 teams.)

Anyway, you gently place your cubes in NaOH solution (I think it is 0.1 percent NaOH, or was it 0.1 M? I forget but can also look this up, if anyone is interested) and stir them gently for about six minutes. During this time, the OH ions diffuse inward and raise the pH. That causes the phenolphthalein to change to a bright fuchsia color. There is a sharp endpoint, so it is quite dramatic when after six minutes you cut the cubes in half, you see a distinct beige colored cube in the middle and a fuchsia border surrounding it. The book tells you to measure the distance that the OH ions (they actually say NaOH, but that is not exactly accurate) diffused in. They then ask the student which is more important, volume or surface area, in determining efficiency. Now, that seems silly to me, because as volume increases from 1 to 2 to 3 cm, so does surface area. So how would a student know how to answer the question? They also ask for a calculation of S:V ratio, which decreases as the size of the cube increases (S:V is 6 times the square of the side divided by the cube of the side, or 6/x, where x is the dimension of the cube -- 1, 2, or 3 cm, in this case). My smarter students pointed out that to really answer this question, one would have to have two solids of the same volume but different shapes and thus different surface areas. So that is what I have done.

Also, instead of asking the students to measure how far the OH ions diffuse in, which is, of course, the same in each solid, over the same time, I have them measure the dimensions of the undyed solid in the center. They then calculate the volume of this solid, divide it by the volume of the original whole solid, convert to a percent, subtract from 100, and voila -- they have the percent efficiency, that is, what portion of the entire cube has been reached by the OH ions. It comes out quite nicely, for those who are careful in their measurements. The percent efficiency decreases from almost 100 percent for the 1 cm cube to something like maybe 70 percent for the 3 cm cube. The 4 x 2 x 1 solid, which has the same volume as the 2 cm cube, has a higher percent efficiency than the 2 cm cube."
-- Barbara R. Beitch, Hamden Hall Country Day School, Hamden, Connecticut. 4/14/00

Answer 2: "Here is a trick that I came up with this year to make cutting the cubes easier (a similar procedure is in the Scott Foresman/Addison Wesley biology text laboratory book, Biology: The Web of Life). After a fiasco, trying to cut the cubes out of a sheet cake pan, I went out this year and bought three plastic ice cube trays for about 50 cents each. If you fill each section to capacity, you will have a cube that is approximately three cubic centimeters. Each group or student can be given two cubes. They will trim one to approximate the three-cubic centimeter size; from the other they can cut the one- and two-cubic centimeter pieces. It cuts prep time down, makes less mess, and the cubes pop out of the plastic trays better than ice ever did! I even found ice cube trays the same color as phenolphthalein in a basic solution... a lovely dark pink! I marked the ice cube trays with warnings and poison symbols so that they will not be used for anything other than the phenolphthalein agar."
-- Jo Ann Burman, Andress High School, El Paso, Texas. 4/14/00

Answer 3: "I think the ice cube tray is a good idea, but here's a twist to using phenolphthalein. We use purple cabbage juice instead, and add a little baking soda to get it to turn green or blue. Then we pop them into vinegar. It works well. Since we also use purple cabbage juice for a pH lab, it is a nice link and the students immediately know what is going on. We have them determine the hydrogen ion movement etc. I think this came out of an old 'idea bank' from the Biology Teacher... can't remember exactly."
-- Patti Carothers, West Laurens High School, Dublin, Georgia. 4/15/00

Answer 4: "Another wrinkle while we are sharing. I have put a little NaOH into my agar so that the initial cubes are red. I then have the students use .1M HCl as the solution. The students can actually see the cubes begin to turn clear, and when they cut them open they see bright red centers. I found that the phenolphthalein (say that four times fast) wash also diffusing out of the cube, and into the NaOH solution, making it red and hard to see what it happening. A safety note: I point out to my students that phenolphthalein is the active ingredient in Ex-Lax, and if they don't carefully wash their hands after the lab, they're going to be really 'regular' people for a few days."
-- Israel Solon, Greenhill School, Dallas, Texas. 4/15/00

Answer 5: "We have successfully made the agar cubes with Bogen's Universal Indicator instead of phenolphthalein and have put the cubes in vinegar. The biggest difference we notice is that vinegar diffuses more rapidly and results can be measured in one minute or less. I imagine other even milder acids might be more successful. The color is a very interesting 'orangey' red. If we put the cubes in a mild ammonia solution, we get a navy blue. The cubes start out as a rather hideous forest green. This way we avoid working with the highly caustic sodium hydroxide."
-- Eloise Farmer, Torrington High School, Torrington, Connecticut. 4/17/00

Suggestion: "I have done this 'hot dog lab' as part of an integrated discipline course called 'Nutrition Science.' We use regular lighter fluid as the solvent, and teaching the students the concept 'like dissolves like,' has gotten terrific results every time! Cut and mass approximately three grams of any hot dog, use a stirring rod (and good ventilation!) to stir the hot dog pieces with approx. 10 mL lighter fluid (the fluid will turn pale and cloudy), decant through filter paper, repeat the process with lighter fluid and same pieces of hot dog for a total of three times. Let the resulting evaporating dish of fluid sit overnight (two nights if at room temperature or one night at approx. 98 C) and you will get unmistakable fat (kids describe it as looking just like vegetable oil) in the bottom of the dish. We have done this with different brands (generic vs. brand name) and different content (chicken vs. turkey vs. beef or no-fat) with terrific results! This is one of those labs the students remember and talk about the rest of the year!"
-- Becky Ashe, West High School, Knoxville, Tennessee. 4/20/00

Question: "I've just received my 'Fast Plant' kit and look forward to a year without the hassle of those light sleeping drosophila. I didn't realize the fast plants were so small. I would appreciate any tips, advice, or cautions from anyone who has used Brassica rapa ('Fast Plants' from Carolina) before."

Answer 1: "Are you familiar with Wisconsin fast plants (Brassica rapa)? Check out their Web site. There are many, many fascinating experiments to be done."
-- Donna Light-Donovan, Croton-Harmon High School, Croton-on-Hudson, New York. 7/21/00

Answer 2: "Congratulations on trying out the fast plants. I have used them very successfully for the past few years. The only recommendation I would make, aside from following the planting and watering instruction booklet, is to either build (as I did... on the cheap with parts from Home Depot and scrap lumber) or purchase the cool fluorescent grow lights... an absolute must. You will also need a fairly large space (grow area) to store the plants during the 45-day cycle."
-- Mark Stephansky, Whitman-Hanson Regional High School, Whitman, Massachusetts. 10/12/00

Answer 3: "I have used fast plants for years now and love them. I keep mine under a fluorescent light bank 24 hours a day. No need for expensive grow bulbs, the plants grow just fine under the cheap $1.00 a bulb variety. I teach all of my plant structure while doing genetics at the same time. Dissect the flowers to learn plant anatomy. In addition to the classic Mendelian genetics lab, have your students design their own experiments on plants. You can use some of your F2 seeds after your genetics experiment for this. Reinforce experimental design!! I also get a set of the gibberellic acid deficient variety and do some work with plant hormones (also reinforces the fallacy of acquired characteristics). The students often think that because you add the gibberellic acid to the plant to make it grow tall, the offspring will also grow tall. I usually get extra parts, stakes, labels, soil (use a carbon free potting soil -- the plants do not like soil with carbon added), wicks, and copper sulfate squares so I can set up individual experiments after our Mendelian genetics lab. The directions that come with the kits are excellent.

The only problem I had was one year we had an aphid infestation. I waited two days to get the aphid soap on the plants and it was a miserable failure. Now I have a bottle waiting for the first sign of aphids. After you are done with everything, wash and rinse, then bleach to kill algae, and most of all the supplies are reusable next year, or for the next project."
-- Franklin Bell, St. Mary's Hall, San Antonio, Texas. 10/12/00

Answer 4: "I, too, used fast plants to have students design an experiment. To save my sanity, I ordered four kits from Wards and/or Carolina-irradiated seeds, fertilizer deficiencies, gibberellic acid, and a Mendelian cross. My four groups of students had the task of researching the background information on each related area and designed their own problem. They collected respective data and created power point presentations to teach the class about their aspect of plant maintenance and presented their problem, hypothesis, controlled procedure, data, and conclusions. We were able to cover significant information on plant hormones and plant nutrition, revisit mutagenic agents and Mendelian genetics. The students get very attached to their plants, or maybe they have found that this is a good way to delay class for five minutes to collect measurements! But I thought it was worth the time. I recommend the fast plant video from Carolina that shows how to set up the plants and the life cycle. It runs about 20 minutes and is worth the time it would take to figure out what gets added when. I, too, kill all plants, but these are very easy to grow with $1 bulbs."
-- Carol Luterek, Maryvale High School.

Question: "I am trying to find some really great activities/labs to do to teach my students the scientific method. I have used the animal behavior lab in this way before simply by having them set up their own experiment. It works well, but I would like to do something different with them. Suggestions?"

Answer 1: "One of my favorite explorations of the scientific method is the 'black box.' Many of you will know this exercise: find a box (cigar, gift, or other cardboard box of roughly six inches cubed). Remove the lid. Punch three holes on opposite sides of the box, just big enough to accommodate three wooden dowels (common at any building supply store). Acquire some metal washers, shower curtain rings, or anything else that strikes your fancy. Insert a dowel through one hole, string some washers, etc. on it, insert through the matching hole on the opposite side. Repeat for the other two dowels. Tape the box closed and paint it black (black box: get it?). Now the question is to design ways to determine what's in the box without actually opening the box. Let the students suggest a technique and how the result will be measured. For example, they might slowly pull one dowel out of the holes and listen for things to drop. They might shake the box. (I suggest putting at least one object in the box but not on a dowel). This box exercise demonstrates the way in which we learned much of what we know about biology -- especially those things we can manipulate but not see (atomic structure, the genetic code, immune system, etc.). Try dividing the class into two teams with competing boxes and see which team can stump the other."
-- Dwayne A. Wise, Mississippi State University, Mississippi State, Mississippi. 8/9/00

Answer 2: "One that we used to do with our regular students involves giving each group two 50 mL beakers and two petri dishes. They put 5 mL water each into one of the beakers and one of the petri dishes. They put 10 mL water each into the second beaker and petri dish. They then counted out four groups of 100 small seeds (grass, alfalfa, mustard). They placed 100 seeds into each of the pieces of glassware and set them aside. After two or three days to a week, they came back and did observations. They saw how many seeds were floating and how many sunk. Were the ones that germinated the ones that floated or the ones that sunk? After making as many observations as they could without removing the seeds, they drained off the water and counted how many seeds germinated in each container. You could then have the students think of other experiments they could do, using the information gathered here (using the amount of water and container that germinated the most, see if light or temperature affects germination). For a biology class, it is rather cool to start off with a lab that actually shows things growing."
-- Jo Ann Burman, Andress High School, El Paso, Texas. 8/9/00

Question: "Has anyone heard of using termites for lab? I finally got my hands on some termites, because I wanted to try the experiment (about) termites following certain kinds of ink -- what kind of ink? What type of chemical is it that the termites can smell?"

Answer 1: "Today was our students' second day of school, and we just did an experiment that worked out great and really got the kids excited about learning biology. I did this last year (my first AP year) too. Collect termites ahead of time from old damp rotting logs or call your local exterminator and see if they'll donate some. Gather the students around one table, and drop 10-15 termites onto a blank sheet of white paper. Tell the students to observe the termites' behavior. They scatter and go off the edge if you let them. Collect the termites (small paint brushes help with picking them up and moving them). Then draw a circle on the paper using a red Papermate ball point pen and drop the termites in the middle. They start walking along the line and go around and around. Tell each student to hypothesize why the termites behave this way; then have them design an experiment to test their hypothesis and predict what will happen. You can talk about limiting variables, control group, constants, etc.

Then have them work in pairs, get their own set of termites (half the fun was seeing them break up the wood chunks to collect them), and perform their experiments. Have on hand several different types and colors of pens and pencils, colored and plain paper, etc. They keep doing different tests as time allows. It is amazing to see all the different ideas the students come up with. What they discover is that the termites are only attracted to certain types of ink. The red Papermate ball point pen, and even the blue and black Papermates, work best. Some of the neon colors of Bic ball point pens work, too, but the other Bics don't. Evidently there is a chemical in the ink that mimics a natural termite hormone, so they think they are following the trail of other termites. (If anyone out there who has done this before can give me a more detailed explanation, I'd appreciate it.) This can lead to a discussion about colonial organisms, insect communication, and lots of other topics. I'm attaching a file of the lab report:

Termite Study Experimental Design Name: _____________________________
Lab Partners: ______________________________
Design an experiment to determine why the termites stay along the line of the circle. Think of a possible cause, write a hypothesis, design a procedure for testing it, and predict what will happen. Be sure that the procedure includes a control set up and identified constants. Then perform the experiment, record observations, analyze the results, and form a conclusion. From the results and conclusion of the first experiment, design a second experiment to further determine why the termites behave this way. Do more testing as time allows.

Problem: Why do the termites walk along the circular line?

-- Joni Driscoll, Northwest Cabarrus High School, Concord, North Carolina. 10/29/00

Answer 2: "I first heard about this termite phenomenon in 1994 at a convention of the Entomological Society of America. I was intrigued by the idea and wanted to know more about how Papermate pen ink mimicked the termite's pheromones, so I contacted an entomologist at Kansas State University. So here is some background information that may be of interest to you if you are considering doing this experiments -- and I agree that it works quite nicely and amazes the students. This is a note that I posted on the 'Access Excellence' Web page in the summer of 1995.

In regard to termites, I spoke to Dr. Ralph Howard (an entomologist with the U.S. Department of Agriculture) who provided insight regarding some of the termite questions that have come up. He is working in a research lab in Manhattan, Kansas, investigating insect damage to stored wheat and corn. A number of years ago his research centered on termites. Regarding the 'species question,' about 95 percent of the termites (in terms of numbers of insects, not number of species) in the U.S. fall into the genus R eticulitermis. There are six species in this genus, and all are subterranean. These six species should all respond to the chemical in the ink, which he assumed was some type of glycol. The natural trail pheromone released by the termites is z,z,e-3,6,8-dodecatriene-1-ol.

There are another 40 orso species, but they are less abundant, living in dryer, warmer areas of southern Florida, Arizona, and southern California, mostly inhabiting dry wood. Those supplied by Carolina Biological are probably OK. The natural pheromone is released from a gland on the underside of the body and is released from the abdomen. They only need to release about one picogram per centimeter for it to effectively mark the trail. Apparently, it was quite an accomplishment to discover, isolate, and identify these pheromones. The chemicals found in ink require much higher concentrations, probably in microgram quantities, which are several degrees of magnitude higher than the real stuff. Termites sense these pheromones through chemoreception, not by sight and not by tactile reception.

First of all, these subterranean species are blind. By placing tissue paper between the termites and the trail, it can be shown that they smell, but don't actually touch the trail. The pheromone is airborne. Dr. Howard suggested extracting the real pheromone by placing termites in 1 mL of hexane. They release a small amount, but enough of the pheromone into the hexane. The hexane can then be dropped onto a surface. The hexane then evaporates, leaving a pheromone trail. The termites of the six subterranean species will all respond to each other's pheromone trails, but they will respond preferentially to those from their own species. That can be shown by making a trail, with a branch going to one side with pheromone from another species. They will stay on the trail marked by their own pheromone, even though they will follow the trail of another species' pheromone if that is the only choice.

Although the use of hexane is a problem to use in schools, there seems to be several opportunities for some interesting experiments. When I teach about pheromones I have the kids sniff some perfume. Then they are told to get down on their hands and knees and follow a 'pheromone' (perfume) trail that I make on the floor prior to the lesson. This is challenging and helps them realize how little they use olfaction for communication. Additionally, I lace the trail with other perfumes. This is all part of an animal communication treasure hunt, which was described in greater detail in The American Biology Teacher (April 1996)."
-- Bob Goodman, Hunter College High School, New York City. 8/10/00

Answer 3: "They are Papermate red, blue, and black pens. Some Bic pens also work."
-- Holly Ellerton, Suffield Academy, Suffield, Connecticut. 9/7/00

Answer 4: "I did it with all colors of Papermate ball point pens. It didn't seem to matter what color. The students LOVED it. They did find out that the termites don't follow corners very well but will try to follow any shape."
-- Tracie Durham, Girls Preparatory School, Chattanooga, Tennessee. 9/7/00

Answer 5: "When I do that lab I supply students with three different brands of ball point pens. The ones the termites are most likely to follow are the Papermate pens. They sometimes follow the others but not as consistently. I also provide students with three or four different colors. Many of them hypothesize that the termites follow the lines based on color. This way they perform an experiment, get a conclusion that does not support their hypothesis, then have to perform a second experiment. They enjoy it."
-- Andrea Prybylski, Westminster Schools, Atlanta, Georgia. 9/8/00

Question: "Besides the enzyme lab, do AP teachers use other biochemistry labs?"

Answer 1: "I use the acid/base lab for the CBL from 'Biology with CBL' from Vernier (can also be done with pH probe and computer). In this the students test initial pH and then add drops of acid/base to determine each substance's buffering ability. It works fairly well if you have a good selection of nonbiological chemicals, biological chemicals, and biological organisms to test. I find that it also serves as a nice bridge to organic and biochemistry."
-- Gena Barnhardt, Hickory High School, Hickory, North Carolina. 8/24/00

Question: "Does anyone have any good ecology labs outside Lab 12?"

Answer: "Try the Ecological Society of America's educational site. It is loaded with good labs. (See "See also.") Also, there are a number of very excellent labs that have been produced on the ABLE (Association for Biological Laboratory Education) Web site (see "See also"); go to full-text articles of proceedings."
-- Brad Williamson, Olathe East High School, Olathe, Kansas. 9/4/00

Question: "My students are about to analyze macromolecules. Does anyone have a fun way to do so? I have heard about a forensic unit where you identify the guilty party based on analyzing the food content. Does anyone know where I could find something like that?"

Answer 1: "The STARS program at Southwestern Medical Center in Dallas, Texas, just did an in-service for teachers on medical forensics. In it they had a 'Crime Lab Activity,' which they got from Access Excellence's Activities Exchange. There is a link to it under "See also."
-- Pebble Barbero, Highland Park High School, Dallas, Texas. 9/24/00

Answer 2: "...(McMush) lab... It originally appeared in the November/December 1994 issue of The Biology Teacher, volume 56, no. 8." Cheryl Hollinger, Central York High School, York, Pennsylvania. 9/27/00

Question: "(Do) any of you folks have a greenhouse? How do you run this space and use this space most efficiently? Can anyone recommend a book that will provide useful instructions?"

Answer: "Yes, we have a greenhouse, and teach a botany course slanted to include horticulture/landscaping/commercial plant growing technology. The students learn, in addition to the academics of botany, how to landscape, landscape design, commercial crop growing, greenhouse management, etc. This fall, for example, we plan to grow a crop of poinsettias for sale at Christmas. It helps the budget, too! We use a McGraw-Hill text, Introductory Plant Biology, and supplement it as needed for the commercial stuff. You should see our school courtyards and entryways that have been landscaped by the students. One courtyard has a water garden. It really adds to the school climate, especially during the pansy/daffodil season and during the holidays. The course is so popular that we have to limit the number of students taking it (three sections this year). A new addition that will include a second greenhouse is now being built. There are a number of books available on greenhouse management that you could refer to. By the way, we are in a typical suburban district, not a rural or agricultural community."
-- Bruce Faitsch, Guilford High School, Guilford, Connecticut. 9/27/00

Question: "Does anyone know how to use Sudan indicator in lab work?"

Answer 1: "I use Sudan III to test for lipids. It reacts with the long chains of the fatty acids and dissolves in substance like lipids and stains them orange. You can qualitatively 'tell' how much fat is in a substance by the intensity of the color. I use things like cream, skim milk, flour, coffee, and other foods for the testing in lab. The students get good results.

P.S.: I forgot to tell you that you have to make extracts of the foods by using 95 percent ETOH and dissolving them in the alcohol. You'll have to play around with the proportions to get the best results. I've tried different concentrations the past two years just to see which works best."
-- Cheryl Hollinger, Central York High School, York, Pennsylvania. 12/19/00

Answer 2: "I use Sudan IV and the positive test is either red droplets or a red layer when the substance is mixed with about 2 mL of water."
-- Rene' McCormick, Carroll High School, Southlake, Texas. 12/19/00

Question: "I was wondering if anyone knows if there are microscope slides that have English words or math problems or something, which are written small enough so that a student can't read what's on the slide just by holding it up, but instead would need to properly focus the slide under HIGH power in order to see what's written. Here's my rationale. Yesterday I did a microscope lab with both my honors and my AP Biology classes, and the number of students who can't focus a microscope properly is just appalling. A slide such as I've described would be a great test question -- what word is on the slide? What's the solution to the problem? The student would get maybe one minute to get the slide with the question into focus. If they couldn't do it, they would get a zero on the question. Guaranteed I'd have students practicing the week before the test on other slides around the lab."

Answer 1: "A teacher at our school has a charm on a necklace that appears to be a cross in a Plexiglas rectangle. In reality it is a book of the Bible [could be trouble depending where you teach -- I'm in the buckle of the Bible belt and can get away with this!]. It would serve your purpose, so perhaps you should contact Christian book stores."
-- Rene' McCormick, Carroll High School, Southlake, Texas. 1/12/01

Answer 2: "How about the slides with red, yellow, and blue threads crossing each other? You could ask them to tell you which is on top of which or have them draw the arrangement properly."
-- Rad Mayfield. 1/12/01

Answer 3: "Here is how you can easily change font size in Word. (My husband is a computer guru!) In Word, highlight the word or words that you want to change, then hold down the control key and hit the "[" (bracket key) if you want to make the font small (it will go down to 1 pixel). Hold down the control key and hit the "]" bracket if you want the font to be large. You can make the fonts any size you want by doing this; it is often easier to do this than selecting font size (which is limited) from your tool bar. You could print this out on clear sticky labels for making microscope slides for the lab idea that you are discussing, but the quality will depend on your printer. I think this would be worth the try."
-- Sandra M. Ivey, Bangor Area High School, Bangor, Pennsylvania. 1/13/01

Answer 4: "I just recall that there are microprints on the new 20 dollar bills for security purposes. Look underneath Andrew Jackson's portrait. On either side of the JACKSON ribbon, there is a row of super small prints. I can't tell you what's on it because it's too small."
-- Hoenie Luk, Abraham Lincoln High School, San Francisco, California. 1/14/01

Answer 5: "Is it possible to find old microfilm or microfiche? Some is readable by eye, but you can require the students to find a particular page, word, or title. You could check at some college library; sometimes they have pieces of microfilm that tears off the end of a roll."
-- Ted Johnson, Mossyrock High School, Mossyrock, Washington. 1/14/01

Answer 6: "...here is a suggestion that can be used instead of tiny words to make sure students know how to focus under high power. In my regular biology class I ask the students to count the number of strands making up a single thread. I use this not only to teach them focus, but depth of field and the value of the diaphragm (greater depth of field with smaller diaphragm setting). Under high power they have to focus up and down across the thread (wet mount, no cover slip) to count the number."
-- Gerry Rau, Lincoln American School, Taichung, Taiwan. 1/24/01

Question: "Anyone have a good way of covering the slide labels when giving a practical?"

Answer 1: "There is a labeling and cover-up tape, one-inch width, that Post-it makes. It should be able to cover the slide labels temporarily without damaging them."
-- Joni Driscoll, Northwest Cabarrus High School, Concord, North Carolina. 1/13/01

Answer 2: "To cover labels on the slides I use the little color dots used as markers. They stick firmly enough to discourage cheating, but come off without marring the label if you do it within a few days."
-- Gerry Rau, Lincoln American School, Taichung, Taiwan. 1/24/01

Question: "I need some information on sea urchin embryology...."

Answer 1: "You can find the whole ball of wax regarding sea urchin embryology at the Sea Urchin Embryology site developed by Stanford (refer to "See also" for link). I suggest you find the purple urchin as a first timer since their eggs are pigmented and cannot be confused with sperm upon harvesting! This is my favorite lab of the year. I had a sophomore student go to the state science fair with this last year -- she explored the serial dilution protocol with the different pollutants as laid out on this site. It was super!"
-- Rene' McCormick, Carroll High School, Southlake, Texas. 1/16/01

Answer 2: "The NABT publication, Biology Labs That Work: The Best of the How-to-Do-Its (1994), has information on using sea urchin embryos in the classroom on pages 118-123. I haven't tried it myself, but it looks pretty comprehensive."
-- Mary Wuerth, Tamalpais High School. 1/16/01

Question: "...I would love to know what you do for the human physiology section. I seem to just have enough time to review the body systems and do the labs in the manual...."

Answer: "For human physiology, I use the A.D.A.M. Interactive Physiology CDs and provide some guidance as to areas to observe. The students enjoy the CDs -- especially the quizzes. We have covered human physiology in seventh-, eighth-, and tenth-grade biology courses; the students really just need to review prior material and go into more detail.

"A.D.A.M. Interactive CDs:
  • Muscular System CD -- supplement with Dynamic Human CD, 2nd edition, and have them describe joint interactions using the human skeleton and diagrams.
  • Cardiovascular System CD -- supplement with AP lab on physiology of the circulatory system. I use the Pasco probes and plan to use the EKG sensor to expand the AP lab.
  • Respiratory System CD -- supplement using the Exercise and Respiration Rate Lab, using Pasco Respiration Rate Sensor.
  • Nervous System CD -- have thought about using Photogate for Reaction Time to Sound, Light, and Touch Pasco Lab. Have not worked through it yet.
  • Urinary System CD -- don't really care for this one -- too much depth. I have gone to the Dynamic Human CD, 2nd edition, more and more.
Plant Physiology:
  • Transpiration AP Lab
  • Plant Anatomy Roots, Stems, and Leaves-mostly slides and laser disk films
  • Plant Reproduction -- flower dissection, pollen germination, and tube growth
  • Plant Hormones -- effects of auxin on coleoptile elongation, root growth, apical dominance, and leaf abscission - Geotropism - Phototropism -- effects of Gibberellins on stem elongation -- effect of light on lettuce seed germination (full spectrum and wavelengths). In some cases, students are applying hormones and, in others, observing results of ones I started earlier.
Most of the labs are from old Helms, Curtis, Keeton, Abramoff lab manuals. I find the students like the time in lab and would prefer this to my talking, or their reading, about this subject. Most difficult thing is to get prepared -- some of these must be set up a couple of weeks to a few days in advance."
-- Paul Gardner, Holland Hall School, Tulsa, Oklahoma. 2/04/01

Tip: "I've done the lab using the Red Beard Sponge (marine sponge) -- it works, depending on the conditions you may not see significant reaggregation until the next day. I'm not familiar with the procedure described in the Miller text. I just forced a piece of the sponge through cheesecloth into seawater. Students took a sample of the suspension and observed the reaggregation on a slide. You can order the sponge from the Marine Biological Supply Co. in Woods Hole, Massachusetts. I believe Carolina & Ct. Valley also supply this sponge."
-- Gail Lima, The Winsor School, Boston, Massachusetts. 3/28/01

Tip: "I have sent the copy of the McMush lab: McMush Lab

Objective: To determine the compounds present in food.

Introduction: Carbohydrates, proteins, fats, vitamins, and other nutrients provide your body with energy necessary to carry on life activities. These compounds are present in the plants and animals you use as food. In this lab, you will test for specific compounds and then determine if those compounds are present in ordinary foods.

McDonald's Happy Meal
graduated cylinder
test tubes
test tube clamp
hot plate
Benedict's solution
Biuret solution
indophenol solution
Lugol's iodine solution
1% silver nitrate solution

Part I: Testing of Known Substances
  1. Protein test: Place 5 mL of the gelatin solution into your test tube. Add 10 drops of Biuret solution.
  2. Glucose test: Place 5 mL of the glucose solution into your test tube. Add 3 mL of Benedict's solution. Place the tube in a beaker of boiling water and boil for five minutes. Use test tube clamps to hold hot test tubes.
  3. Starch test: Place 5 mL of the starch solution into your test tube. Add 5 drops of Lugol's iodine solution.
  4. Vitamin C test: Place 5 mL of the vitamin C solution into your test tube. Add 5 drops of indophenol solution.
  5. Chloride test: Place 5 mL of the salt solution into your test tube. Add 5 drops of silver nitrate solution.
  6. Record your results in a data table (as shown below).
Food Substance Reagent test Results
Gelatin Biuret solution
Glucose Benedict's solution
Starch Lugol's iodine solution
Vitamin C indophenol solution
sodium chloride silver nitrate solution

Part II: McMush
  1. Place the Happy Meal in a blender. Add enough water to cover and blend until you get an emulsion.
  2. Filter the mush into a beaker.
  3. Predict the substances you will find in the McMush solution. Record your predictions in the data table using a + or -.
  4. Repeat steps 1-5 above using 5 mL of the McMush solution.
  5. Describe and record your results.
Food Substance Reagent test Results
Protein Biuret solution
Sugar Benedict's solution
Starch Lugol's iodine solution
Vitamin C indophenol solution
sodium chloride silver nitrate solution

Error Analysis:

-- Bob Heun, Brooks School, North Andover, Massachusetts. 3/15/01

Question: "Has anyone out there done the calorimetry CBL lab? If so, what foods did you find worked best to burn? When I saw it done as a demonstration at a workshop they used peanuts and marshmallows."

Answer 1: "In my very low tech lab we use the old fashioned calorimeters. Marshmallows do indeed sound messy. We use a variety of nuts from a can of mixed ones. I think the procedure was from an old BSCS Blue book. There were significant differences between peanuts, cashews, filberts, brazil nuts, almonds, and cashews."
-- Mary Jane Davis, Red Bank Catholic High School, Red Bank, New Jersey. 5/29/01

Answer 2: "I use peanuts, walnuts, and cashews. They give very good results in the CBL calorie lab. Marshmallows are indeed very messy!"
-- Doug Herman, Iowa City West High School, Iowa City, Iowa. 5/29/01

Answer 3: "Cheetos work great, too!"
-- Bob Goodman, Hunter College High School, New York City. 5/29/01

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