Learning about Research, Technology, and the
Nature of Science
Anne Bowen, Science Education Student, Curry School of Education, UVa
Would you like to spark your students' natural curiosity while teaching them authentic research skills and essential knowledge about the nature of science and the use of technology?
This website is designed as a resource for biology and ecology teachers. Described is a classroom research project that involves students in an observational study in which they make careful observations on the life cycle of the Painted Lady butterfly.
Students capture the metamorphosis in journal records and with digital cameras and microscopes. Challenge them to capture processes they've never seen (i.e., a caterpillar turning into a chrysalis) with time-lapse photography!
This project is enjoyable, relatively inexpensive, and dynamic. I implemented this project in a high school biology class, but it can be easily adapted for middle and elementary school. Much of what I describe could be altered to best fit your teaching environment. Enjoy the site, and happy butterflying!
NATURE OF SCIENCE
What does it mean to talk about the nature of science?
In general, the nature of science refers to key principles and ideas which provide a description of science as a way of knowing, as well as characteristics of scientific knowledge. Many of these intrinsic ideas are lost in the everyday aspects of a science classroom, resulting in students learning skewed notions about how science is conducted.
What are the main ideas regarding the nature of science?
1. Scientific knowledge is tentative. Although scientific knowledge is supported by a wealth of data from repeated trials, it is not considered the final word. Scientific knowledge is at the same time stable and malleable. Scientists continually test and challenge previous assumptions and findings. After all, science is a human endeavor, and we know human perspective is limited and fallible. This idea of fundamental uncertainty is vital to scientific studies and is the basis of great scientific discoveries.
2. Nature of facts/hypotheses/theories. Some key words in science are often misinterpreted.
Facts.
Students often think of the pieces of scientific knowledge they learn as "facts." As mentioned in the last section, we should not refer to scientific knowledge as fact, because that would tend to perpetuate the idea that scientific knowledge is inalterable. Scientific facts are observable phenomenon in a particular situation. "Dinosaurs were cold-blooded" is not a scientific fact, because this phenomenon cannot be observed. "The caterpillar is 2.6 cm in length" is an example of a fact, because the phenomenon was observed in a particular situation.
Hypotheses.
If you ask a student to tell you what a hypothesis is, you will likely receive the following response: "A hypothesis is an educated guess." Although a hypothesis is partly a "guess" in the sense that it is an idea, this inevitable definition is not adequate. A hypothesis is a statement, based on previous observations, that can be tested scientifically. The idea that a scientific hypothesis must be testable often eludes students.
Theories.
In the colloquial, theories are often ideas that have not been validated. In science, a theory has a much stronger meaning. Scientific theories are broadly based concepts that make sense of a large body of observations and experimentation. Because theories successfully tie together such a huge amount of information, they are among the most important ideas in science.
3. Scientific methods. In the first chapter of most science textbooks, there will be a section laying out "the scientific method," a step-by-step process that apparently must be followed in order to conduct scientific studies. The danger in this approach is not only that learning the scientific method is a bummer to students, but that it is also quite restrictive in its scope. Scientists usually do not walk through the method sequentially. They often bounce around, perhaps forming a new hypothesis during experimentation. Studies in which no experimentation is performed are also valid scientific studies, but do not follow the scientific method. For example: Jane Goodall observed the behavior of the apes in Africa and did not experiment on them, yet her research is still considered science. This butterfly study is a good example of an observational study which does not follow the scientific method, yet students record scientific data and create scientific conclusions.
4. Observations and inferences. It is important for students to understand the difference between observation and inference. However, this knowledge in itself is not enough. Students should also learn to make good observations and inferences, and understand the role that observations and inferences play in the development of scientific knowledge.
Observations.
When we describe an environment based on our five senses, it is called an observation. For example, "Upon magnification, the painted lady eggs appear bluish and barrel-shaped." Observations are direct enough that most would make the same observation in the same situation.
Inferences.
When we bring our past experience into making a judgment based on an observation, it is an inference. For example, "The caterpillar appears as if it is about to form its chrysalis" is an inference, because you are interpreting observations according to knowledge from past experience. Inferences are important in science in making explanations, but one must be careful not to confuse observations with inferences when conducting a study.
5. Human error. Although we take steps not to make errors in observation or experimentation, scientists are still human and make mistakes. It is important to challenge students to view their mistakes or unexpected results as potentially helpful. Scientific studies are most often riddled with problems that must be addressed. Often, scientists do not find the answer they expect, but if they do not allow their expectations to cloud their judgment, they may be able to approach the problem in a more appropriate manner.
How can I incorporate nature of science activities in my classroom?
In the butterfly study, several nature of science ideas emerge and can be incorporated into mini-lessons:
Pre-research activities: Mystery Tubes, Fossil Footprints, or Dino Bones. All of these lessons focus on hitting home the idea of observation vs. inference.
During research: Uncertainties and observations in Journals. Student records of observations in their research journals is assessed by the teacher. Also, students may be having some trouble with the study design or raising questions and making inferences that could lead to hypotheses. It should be made clear that science is not usually cut and dry and that their concerns and questions are important and should be recorded and discussed.
Post-research: Scientific method debunked. After the study, students are asked to fit parts of this research into "the" scientific method. Their surprising realization that it doesn't fit will powerfully demonstrate a point about science.
Where can I find more resources on the Nature of Science?
BOOKS:
Teaching About Evolution and the Nature of Science, National Academy of Sciences
This book explains the concept of the nature of science, and contains great lessons on presenting nature of science principles and evolutionary concepts. Entire text available free of charge online at: www.nap.edu/catalog/5787.html
WEBSITES:
Evolution and Nature of Science Institute
www.indiana.edu/~ensiweb/natscimn.html
Paper describing the facets of modern science and scientific knowledge.
Science for all Americans: Project 2061
www.project2061.org/tools/sfaaol/chap1.htm
Detailed description of nature of science principles and expectations for American science
www.project2061.org/tools/benchol/ch1/ch1.htm
National Benchmarks by grade on Scientific world view, scientific inquiry, and the scientific enterprise
ONLINE LESSONS:
Evolution and the Nature of Science Institute
www.indiana.edu/~ensiweb/natsc.fs.html
Excellent source of lesson plans covering a variety of topics concerning the nature of science. See also the paper describing nature of science topics, listed under the "Websites" heading.
FOR STUDENTS:
Encyclozine Webpage
http://kosmoi.com/Science/Method
Good online resource for kids to explore nature of science concepts
TECHNOLOGY
INTELPLAY QX3 MICROSCOPE:
MAGNIFIED STILL IMAGES, MOVIES, AND TIME-LAPSE
The "QX3," as we call it, is an excellent tool to have in the biology classroom. We used the microscope earlier in the year to capture parasitic wasps emerging from a tomato hornworm larvae and spinning cocoons. The kids were immediately hooked! We also used it to capture the germination of mustard seeds on a wet paper towel. The students were amazed by how quickly they sprouted, as they watched the seeds move around with their emerging cotyledon.
I used the following activity to give students an introduction to the different functions of the digital microscope:
Abe Lincoln on a Penny
60x
(Photo taken with QX3 microscope)
Part of this introductory lesson includes a plasmolysis activity with red onion cells. A more detailed description of that lesson plan is linked below:
This lesson, as well as the butterfly research, works better with more than one microscope in the room, particularly when trying to capture time-lapse movies of different butterflies. However, they can be accomplished with just one scope. In this case, students would rotate their use of the microscope.
DIGITAL CAMERA:
STILL IMAGES
The digital camera, easy to use and accessible, was the perfect technology to capture the full effect of the research. This was used for long-range shots that could not be taken with the QX3, but worked equally well for close-ups on the butterflies. Many of the students may know how to use the camera, but a short introduction to its functions is necessary for those who are not familiar with it.
WEBPAGE DESIGN:
For the design of the website created by my students, Dreamweaver Macromedia webpage design software was used, as it was most accessible at the high school. Other webpage design programs, such as Microsoft Frontpage or Netscape Composer could be used.
Link to my students' research webpage
MATERIALS
The following is a list of the materials I used for this research project. Materials listed were ordered through both Carolina Supply Company and Ward's Natural Science catalog, but could be substituted for similar materials based on your space, time, or budget considerations. On the "Research Timeline" page, I provide suggestions for alternate approaches and materials.
MATERIALS AND DESCRIPTION
1. PAINTED LADY BUTTERFLIES
I purchased two dozen from Carolina Supply Company. This way, nearly every student could have their own butterfly. They arrived in a small plastic container in pairs and arrived in the larval (caterpillar) stage:
Price: $18.95 for 30 larvae (Carolina Supply Company Catalog)
2. BUTTERFLY HABITAT
This was the center of attention after the caterpillars turned into chrysali, as they are transferred to this new home. The habitat should be sturdy and fairly transparent for viewing. It should also be easily accessible. I purchased a nice black-netted reptarium from Carolina. It has side zippers for easy access to the inside:
Price: $65.00 (Carolina)
3. LAMPS
The habitat should be enhanced with light from the outside. I used clamp spotlights. A bonus, besides being able to light up the Painted Ladies, is that the adults are attracted to the light and become more active for viewing when you turn them on.
http://www.wardsci.com/EC//products/catalog/?categoryID=15349
Butterfly attracted to lamp light, which is resting on top of habitat:
Price: $5.25
3. HOLLYHOCK OR MALLOW PLANTS
The Painted Ladies lay their eggs on member plants of the mallow family. I picked up about 8 hollyhock plants at a local flower dealer. The plants performed well in the habitat. Mallow plants are available to order through Carolina. However, I would warn against ordering plants through the mail -- I experienced some difficulty reviving the wilted mallows I received. And the butterflies seemed to love the hollyhocks:
Another possibility is to try using common thistle, another host plant for the butterfly. Depending on the time of year, you may be able very economically to transplant some from a field or roadside.
Price:
Thistle- free!Mallow plants- $8 per plant through catalog
Hollyhocks- about $3-4 per plant (but local plant dealers may be generous if you tell them about your educational intentions for the plants- I scored 8 for $12)
4. DIGITAL MICROSCOPE
The IntelPlay QX3 Microscope was marketed as a children's toy, but is an excellent tool for capturing close-up shots and time-lapse images of the stages of the butterfly life cycle (from caterpillar still shots to movies of the adult butterfly emerging from the chrysalis). As seen in the pictures below, an incredible feature of this microscope is that it can be used in its upright rest, or as a handheld device:
www.nfld.net/teacherschoice/ flyer3_.htm
Price:
PC compatible: $30-100. Most stores have discontinued sales of this product, but check eBay -- you'll find many for sale. Another source: compuvisor.com for under $50
Mac/PC compatible: $160. Neo/Sci now sells a version of the microscope that works on both platforms and comes with a curriculum guide complete with directions and 36 suggested activities with the microscope. You can find more information at neosci.com
5. COMPUTER
You will need a computer in order to view the images from the digital microscope. The computer will serve as a workstation for the students when using the digital microscope:
6. DIGITAL CAMERA
The digital camera will allow students to record their observations to reflect upon later. They can use the images in their final natural history report on the Painted Lady life cycle, and can also use them effectively to show others what they observed via a project website. My students put a website together using only pictures they took with the digital camera. We borrowed cameras from the school's media center.
View my student's research website
Price: $200 to $2000
7. TEST TUBE RACK
When the caterpillars turn into their chrysalis form, we transferred them to a hanging position in the large habitat. To do this, we rested the cheesecloth to which they are attached over the holes in the test tube holder, with the chrysalids hanging freely through the holes, ready for hatching. This setup is seen below, to the right:
Example Test Tube Rack
http://www.sciencekit.com/Products/Display.cfm?categoryid=319545
Student Photograph of Our Setup
Price: $5-$15
8. GUIDE BOOK
After the butterflies emerge, and the students have a chance to describe them, they should have a guide book in order to identify the species. Until this point, the identity of the butterfly species should not be revealed.
The Golden Guide to Butterflies and Moths is a great reference, showing the insects in different stages of development, as well as providing distributing maps. They are also the most affordable that I have found! Another option is to borrow a guide from the library or from another teacher. Your students really don't need more than one or two (my students had one), as some can use the book when others are making observations.
http://www.vintagepbks.com/gg-titles/butterflies.html
Price: $6.95
9. SWALLOWTAIL CRYSALI
These are supplementary to the research with the Painted Ladies. I purchased three Spicebush and three Tiger Swallowtail chrysali. Below is a picture taken of each species. The students can compare these two species' appearance and development to that of the Painted Ladies, but this is optional. Our swallowtails did not start to emerge for months after the Painted Ladies, so don't give up hope on yours! They're not dead, but they are awfully slow to emerge...
Price: $21.50 (Ward's Mixed Swallowtail Set)
10. HANGING NET HABITATS
The swallowtail chrysali were housed in smaller, less expensive habitats like this one.
http://www.kidstoychest.com/habitats/bug-habitat-butterfly-house.htm#il3110
These habitats are not as useful for the Painted Ladies due to the fact that they are not as easily accessible from the outside. You must untie the cord at the top to enter. Since the swallowtail pupae take a long time to hatch and do not require much attention, these habitats worked well in housing the slow-pokes. We had two hanging habitats, one for each of the species.
Price: $12.00 each
RESEARCH TIMELINE
The following is a general outline for this research project:
TOTAL TIME NEEDED: 4 WEEKS
IN CLASS TIME: 5-20 MINUTES PER DAY
TIMELINE OUTLINE:
(Day 1 is the day on which the caterpillars arrive, and day 30 means 30 actual days after they arrive, not 30 school days. Spans of dates attempt to account for differences in growth rates of the butterflies, and factors in weekends)
DAY 1: Nature of Science: Observation vs. Inference, and Introduction to Butterfly Research (Time: 20 min)
Because this project is largely based on careful observation, students will need to be able to distinguish between their observations and inferences. For a more detailed description of the two, see the "Nature of Science" page. Because I introduced observation vs. inference earlier in the year using the Mystery Tube activity, I used the Dinosaur Bones as a refresher right before this project.
1. Choose at least one of the following lessons that teach the distinction between observation and inference:
2. Hand out a description of the project, summarizing expectations for the project, including the fact that they will be using digital microscopes to record events in the butterfly's life cycle, eventually identifying the species.
This should excite them... my students could not wait to use the digital cameras and microscopes!
DAY 2: Bring on the Caterpillars: Journals and Intro to Scientific Data Collection (20 min)
1. Before the students receive their caterpillar (oh, what a moment!) they need to learn about the importance of good scientific journal keeping. My handout (linked above) includes a list of five main points on which the students should focus in their daily entries:
- (1) Description of appearance
- (2) Behavior
- (3) Sketches
- (4) Measurements
- (5) Comparisons to other butterflies in the class
Emphasize the importance detailed observations and of making observations only (no inferences!), in order to avoid bias. I also explained that the words larvae and caterpillar are synonymous and made sure my students were spelling them correctly.
2. Assign a larvae cup to student pairs. The larvae will arrive in two's inside a small, clear plastic cup, complete with food to last. Label the cups by letter. Students must immediately choose one of the caterpillars as "theirs," which will likely require very careful observations of appearance and behavior. Emphasize this point to the students.
3. Initial measurements should be made with a metric ruler, to the bests of the students abilities. They may have to estimate if the caterpillars are not stretched in a straight line. Students should take the time to carefully sketch their caterpillar and to compare it to others in the class.
Alternatives: Measure the mass of the caterpillars. The method suggested for transfer of the larvae is by paintbrush, so as to avoid damaging their fragile bodies. I chose to not have the class do this for fear of disrupting the larvae too much, but I think that this would be a more accurate measure of growth if coupled with the length and width estimations. I would try this the next time I set up this project.
DAYS 3-10: Continued Observations of the Larval Stage (5 min/day)
1. Encourage students to make careful observations of their caterpillars over the next several days. Likely there will be no major changes in appearance, besides rapid growth. Make sure that the students make careful observations of the caterpillar behavior -- the way it moves, how it eats, how it interacts with its container-mate. They may be able to observe the larvae shedding their exoskeleton. The larvae will go through several growth stages, or "instars," before they pupate. The exoskeleton will appear as a small black clump at the bottom of the container.
2. While students are busy recording observations in their journals, you can fill them in on some missing links:
The larvae are busy munching on yellow mush at the bottom of their containers. What would you suppose they would eat in their normal environment?
Do you think the larvae would behave differently in their normal environment? Why or why not?
What could be a function of the caterpillar spines, or hairs?
This is an excellent opportunity to talk about the characteristics of insects...but don't give too much away about butterfly life cycles. Since we had just finished a unit on classification, I prompted my students to help me write out the nomenclature for the Order Lepidoptera (butterflies and moths). Kingdom Animalia, Phylum Arthropoda, Class Insecta, Order Lepidoptera. We reviewed the features of each group. Don't give away anything else! That is their challenge -- to name the species. At the end of the project, they filled in the missing levels: Family, Genus, and Species.
3. If the students have not yet had the chance to practice using the time-lapse feature on the digital microscope, make sure they do during this time period. Sample exercises to acquaint them with the microscope functions are provided under the "Technology" page. In addition, students should take some pictures of their growing larvae using the digital camera.
Soon your students will be able to capture an incredible transformation...
DAY 10-12: The Chrysalis Formation (15 min, one day)
1. Students will begin to observe that their caterpillars are hanging from their hind "legs" from the top of their containers, forming a J, or hook-shaped position:
My classes witnessed several of the caterpillars in this position on the 10th day of observations, although the timing is different for each caterpillar. Let them observe for themselves that this hanging position is a clue that the larvae will be shedding their exoskeletons to reveal a chrysalis, or the pupal stage, underneath. The chrysalis is the last skin of the larval stage.
2. Now it is time to set up the digital microscope. If students spot their caterpillar assuming the J-shape, they should carefully remove the cheesecloth to which it is clinging. From here they should position it on the top of a hole in a test tube rack, with the caterpillar dangling through the hole in plain view. My students developed their own microscope rig, by removing the handheld portion of the microscope and attaching it by velcro strips and masking tape to a box anchor, or stage.
You can suggest that your students try this setup, or scheme up their own... I'm sure there are better designs!
Alternative: Other students set up an alternative rigging in the small net habitats for the swallowtails. They clamped a microscope to a ring stand, taping the caterpillar to a clamp above for a unique view from the bottom.
Capturing the process in time-lapse normally involves some trial and error. Once you have the QX3 aimed and focused at a hanging caterpillar, set the time-lapse function to take a snapshot every 15 seconds. The movie will run for approximately 1 hour, and can be left unattended during this time. The time-lapse will need to be reset if nothing has occurred by the end of this time period.
My students caught one of the larva turning into its pupal stage, and the rest happened over the weekend, supporting the existence of "Murphy's Law" in science!
Click this link to see their movie in Quicktime (.mov file)
Click this link to see their movie in Windows Media Player (.avi file)
This video was recorded for approximately 15 minutes during class, with the time-lapse set to take a snapshot every 30 seconds. I would suggest trying a shorter lapse time between each snapshot, as mentioned in the explanation above, to capture a smoother sequence.
During each class the next day, students watched the movie that their classmates made the day before. I had never seen the kids so interested, grossed out, and proud.
DAYS 12-18: Setting Up Habitat and Time Lapse (5-20 min, different days)
The chrysali should remain in their pupal form for about 8-10 days. Within this time, the habitat must be set up in preparation for the emergence of the the adult butterflies.
1. Students continue to make observations of their chrysali. There will be little noticeable change during this period. (5 min)
2. While the chrysali are silently changing inside their shell, the students can be busy arranging the habitat. The teacher must provide the appropriate host plant: I used the hollyhock. Although the students do not know the identity of the butterfly species, they should research the importance of host plants to lepidopteran species. My students completed a homework assignment on host plants and researched butterflies as bioindicators (see step #4).
3. Students should also prepare the adult butterfly food and feeders. To prepare the nectar:
Mix a 5% sugar water solution. By boiling the water, the solution will be sterilized and will last longer. Place sugar solution in a container and refrigerate until adults emerge.
The larvae should have come with feeder containers, complete with wicks. If not, students can construct feeders. Take small plastic containers with lids and punch a hole in the lid. Roll a wick made of cotton, and place it through the hole to the bottom of the container. (10 min)
4. This is also a good opportunity to discuss bioindicators. Butterflies are good bioindicators of changing/declining habitats due to their reliance on specific plants on which they will lay their eggs. (10 min) I asked my students to complete a homework assignment on endangered butterfly species and the cause of the decline.
5. Finally, when all caterpillars have turned to chrysali, it is time to move them into the habitat. Some likely will have fallen from their webbed attachment to the cheesecloth at the top of the container. We took these poor guys and glued them to the cheesecloth with some Elmer's. Stress to the students that this must be done with care. Students may be surprised that some of the chrysali will start to squirm violently upon being touched. (20 min)
6. When the glue has dried completely, the chrysali may be placed in the test tube racks and put inside the habitats. Place the original labeled container next to its corresponding chrysali, so that students can continue to observe their own organisms.
7. We found it useful to set up a microscope aimed at a particular chrysalis, and keep a careful eye on others that appeared ready to emerge. My students used the same small box, masking tape, and velcro stage they had used for the caterpillar to chrysalis conversion. Ask the students to help brainstorm ways in which to arrive at the most effective setup -- a great lesson in creative problem solving during scientific research.
DAYS 18-20: Adults Emerging and Time-lapse Footage (5-10 min)
1. Students should begin to see adult butterflies emerging after about 9 or 10 days in the chrysalis. The chrysalis will begin to turn transparent, and you should be able to see the blacks and reds of the adult wing through the chrysalis skin. We failed to capture this process on an appropriate time lapse, as is apparent in the movies below. All but one of the butterflies emerged over the weekend!
Missing this event firsthand was frustrating to the students. However, it provides for a good lesson about the limitations of scientific research. Also, they did capture some great footage of a chrysalis becoming increasingly transparent.
Watch adult Painted Lady emerging from chrysalis in Quicktime (.mov)
Watch the same movie in Windows Media Player (.avi)
2. Convince the students that now is the time to make their most careful observations, so that this event can be captured. If students notice changes in one of the chrysali, this should be repositioned in front of the QX3 microscope. Start recording a time lapse movie, and continue to reset until the adult emerges. Let the recording run after school to check the next morning, if possible.
A useful frame setting would be one picture every 20 seconds.
3. Once the adult butterflies have emerged, ask students to sketch them and make observations about their behavior.
They should be able to watch a butterfly feed on the prepared nectar using its proboscis as a coiled straw. My students used the QX3 to make handheld movies of this behavior.
Watch movie of butterfly feeding in Quicktime (.mov)
Watch movie in Windows Media Player (.avi)
Students should observe the way the adult will pump its wings as it drinks, creating negative and positive pressure, which allows it to suck in the sugar-water. Also note the number of appendages, the use of its antennae, and its distinct markings.
Set up the spotlights on top of the habitat, and observe how the butterflies become more lively, fluttering around to a greater degree and resting near the light. Ask students to make inferences about this observed behavior, and to note these as inferences in their journals.
DAYS 18-22: Identifying Species, Mating, and Life History Report (5-10 min)
1. Now it is time to help the students identify the species. Provide them with a guide book, which they can use to figure out the common name (Painted Lady) and scientific name (Vanessa carduii) of their species of butterfly. In my classes, one student read the description, then passed the guide book to the other students to view. I reviewed the taxonomic breakdown from kingdom to species, as well as the importance of providing both common and scientific names for a species. We also discussed life history characteristics that would not be revealed in their observational research (such as migration, over-wintering, and distribution of the Painted Lady). (10 min)
2. The adult butterflies will begin mating within a day or two after emerging. Make sure students understand what they are doing -- the butterflies have a unique approach:
Ask your students to observe the butterflies carefully. Can they tell the male and female apart? We never figured it out for sure.
3. Hand out rubric for Life History Report. (5 min)
I explained that the purpose of this report was to detail the life and metamorphosis of the butterfly using observations. This is a summary of their journal notes from the semester, written as though the reader is from Antarctica, and knows nothing about butterflies.
DAYS 22-24: Laying Eggs (15 min)
The adult butterflies are ready to lay eggs about four to five days after they emerge and will continue to lay eggs for a few days. The eggs are tiny, and difficult to see unless you observe closely. Many of my students saw the females depositing eggs on the leaves, and tried again to make observations to distinguish females from males. Other students observed that the females were laying eggs in patterns on leaves, and also spreading the eggs between different leaves. This is a great opportunity to take a movie, or still picture of the beginning of the next stage in the butterfly life cycle. Make sure that all students have had a chance to use the QX3 and its different functions: still images, movies, and time-lapse
This is the fourth and final metamorphic stage of the Painted Lady butterfly life cycle. It is important for the students to view the eggs with the digital microscope in order to be able to accurately observe and sketch the egg. They will appear translucent and bluish-white, and are shaped like a barrel with ridges down the sides.
DAYS 25-29: Larvae Hatch, Overpopulation, Work on Final Report (5-15 min, computer lab work on report- 45 minutes)
1. Larvae will begin to hatch within 3-5 days after the eggs are laid. Noting the tiny size of the eggs from which they emerge, you will realize that the caterpillars must be tiny at first. Suggest that students look on the underside of leaves, where they often tend to hang out. They will also start to spin webs, much like what was seen in the feeding containers in which the original larvae were sent.
Make sure that students understand that these are different organisms than the original caterpillars. The fact that sexual reproduction took place and new individuals were formed eludes some of the students. (5 min)
2. Within a few days, the voracious larvae will have decimated the hollyhocks or mallow plants on which they are feeding. There are just too many for the size of the habitat. Unfortunately, I did not catch this problem until a Monday morning when I realized that there were no living caterpillars remaining. Discuss overpopulation with students. (10 min)
Alternatives to Death: a) You could try to maintain a few caterpillars in the habitat and get rid of most, but it is hard to collect the little guys, b) You might also try to replenish the stock of host plants, or c) You might order more caterpillar meal from Carolina and try to start the process over again. This time the students could release the adult butterflies as soon as they emerge, in hopes that they could seek out their own host plants.
3. Allot time in the computer lab for the students to work on their Natural History reports. They can find their favorite pictures taken with the camera or microscope to document the metamorphic stages visually, making a more colorful and interesting final product. It would not be necessary to take class time to work on the report, but if possible, it would be worth it. Some students may not know how to insert pictures into a Word file; including instruction on this during computer lab time could prove very beneficial to them. (45 min)
DAY 30: Discussing Scientific Methods (10 min)
As soon as students turn in their final reports, I wrote the basic steps of "the scientific method" on the board.
1) identify problem
2) state a hypothesis
3) design an experimental setup to test hypothesis
4) collect data
5) analyze data
6) communicate results
Then, I asked students to identify the parts of their butterfly research study that fit in each step of the method. Most students force-fit the steps, but in reality, this study was not experimental, and did not follow this method. They may have identified the problem being that they wanted to learn more about the life of a butterfly species. Also, they collected observational data, and they did communicate their resulting observations through a webpage, but the rest of the steps do not apply to their research.
When probed as to whether they actually made a hypothesis, students began to see the difference between an experimental and observational study. We are often able to identify a problem to be studied in an experimental design after we make careful observations, but this is not a necessity in the scientific inquiry process.
I asked students to identify a hypothesis that they would like to test after having done this observational study. Ideas included raising a test group of butterflies in a warmer or colder room to examine growth rate, or testing the effect of pesticides, such as BT, on the Painted Lady larvae.
I asked the students to decide whether or not they thought their project was something a real scientist would do. I also asked them to identify scientists (e.g., Jane Fossey) and other scientific studies that do not follow a strict scientific method (i.e., paleontology). Finally, I emphasized the importance of the scientific method in many scientific research projects. My students had concurrently worked on an experimental study on acid rain's affects on plant growth, where they did follow a more direct scientific method. This served as a great comparison.
Day 30+: Life History Reports Due and Webpage Design
1. Life History Reports are due at appropriate point after the concluding lesson on day 30. I gave my students 2 days, since they had known about the report well in advance and had the chance to work on it in class.
2. My students designed a webpage to communicate the results of their research, using the pictures and movies they had taken during the study, and describing the life process of the Painted Lady. This was accomplished on a volunteer basis for extra credit during lunch periods and study halls. For more on this process, see the "Technology" and "Assessment" pages.
Project Extensions
If you haven't had enough butterflying yet, there are many possible avenues of extension for this project.
1. Experimental Research. Now that students understand the importance of observational research in science, this is the perfect point to use those observations as the basis of experimental research on butterflies. Replacement larvae are not very expensive, now that you have the equipment set up. You could work with a student's hypothesis based on the previous butterfly observations (i.e., testing the growth rates in cold and warm environments, the effect on adult development of turning the chrysalis upside down), or use a completely different topic that would tie in with your current unit.
2. Raising Butterflies. Instead of allowing the newborn caterpillars to die, challenge students to design a survival plan. Can all the caterpillars be saved, or will some have to be sacrificed for the good of the others? Food meal can be ordered from Carolina, or the students may attempt to raise a few caterpillars exclusively on their host plants. If this extension is chosen, it must be introduced before the eggs hatch, so that students have time to formulate a plan.
3. Endangered Species Recovery Plan. If students are interested in endangered butterfly species, they could research the life history for a species, and with their new-found knowledge about the butterfly life cycle, create a plan for this particular species.
4. Butterfly Garden. Students learned about host plants in this research project. Challenge them to create a plan for a butterfly garden that would attract many different species in the area. They would need to research different local butterfly species and their host plants. They could choose a location for the garden at their school, or another local site. This would be an excellent group project, utilizing skills unique to different students. Certain students could develop a landscape layout for the garden, other students could be in charge of raising funds to pay for the plants, etc. The following is an excellent web resource compiled by the USGS for the butterflies of North America:
Butterflies of North America - www.npwrc.usgs.gov/resource/distr/lepid/bflyusa/bflyusa.htm
The following map will allow you to discover the butterfly species living in your own county:
Butterflies by County - www.npwrc.usgs.gov/resource/distr/lepid/bflyusa/chklist/chklist.htm
5.Use your imagination! As Albert Einstein said, "Imagination is more important than knowledge." Encourage kids to be thoughtful and creative, and discuss ideas with them about extensions for the butterfly project.
ASSESSMENT
POINT SCALE FOR RESEARCH
50 points (25 points each grading)
50 points- Natural History Report
20 points- Homework assignments
120 total points ( + optional extra credit )
JOURNALS
Students were graded on their journal observations, which they turned in twice: once at a midpoint during the chrysalis stage, and again at the end of the research, when they turned in their life history reports. Journals were assigned a score according to thoroughness and completeness of observation. Both grades for the journal were based on 25 possible points, for a total of 50 points for the entire journal activity.
To view the rubric, click here
I wanted the journal to count for as much as the natural history report in order to emphasize the importance of making careful observations and taking accurate records in science.
NATURAL HISTORY REPORT
The natural history report was the final summary of the Painted Lady's life cycle, as observed by each student. I counted this as a 50-point assignment.
To view the assignment, click here
20 points could be earned in the introduction, where the students described observations vs. inferences, and the difference between observational and experimental research in science. The bulk of the report, the life history section, was worth 30 points. Here students described each stage of the Painted Lady life cycle, using the observations they made and recorded in their journals. They were also encouraged to include pictures of each stage in their report during the computer lab visit.
HOMEWORK ASSIGNMENTS
Homework associated with the research can be assigned at any point deemed necessary or plausible. For example, I assigned homework twice during the research. One assignment was based on host plants and butterflies, and the other was on the idea of butterflies as bioindicators. Another option is the differences between butterflies and moths. Each was worth 10 points.
EXTRA CREDIT: WEBSITE
From the beginning of the project, my students knew that they would be putting a website together on the project. This was not only a great way to teach students about the importance of communication in scientific research, but it was also an excellent motivator in taking digital camera and microscope images. Most of my students wanted to be famous!
Students who volunteered to help with the webpage received 30 extra credit points on the project. I split up responsibilities, and students signed up for whichever task appealed most to them. Examples of tasks included:
- Organizing digital camera pictures from each class
- Writing a blurb on a certain part of the life cycle (i.e., egg stage)
- Describing observation vs. inference
- Webpage formatting and design
Students worked on these website-related tasks during free-periods when I was in the room. I gave mini-lessons to students interested in learning to use webpage design software. When it was completed, they were very proud of showing others their accomplishment! To check out their website, visit the URL below. My students took all the pictures and movies- and yours can do the same!
http://www.k12albemarle.org/AlbemarleHS/ClassPages/Otis/butterflypages/butterflypage.