A massive ice bridge, 40 km long and more than 500 m wide, that once connected two islands is no longer. See http://earthobservatory.nasa.gov/IOTD/view.php?id=36060 for a great visual: a labeled photograph of the area. The ice bridge had been in place for hundreds, probably thousands, of years and held back the Wilkins Ice Shelf. Now scientists believe the ice shelf, which has been receding since the 1990s, along with a number of other Antarctica ice shelves, will accelerate its recession. The short- and long-term impacts on sea level cannot be accurately predicted.

Rueters.com has the story, Ice Bridge Holding Antarctic Ice Shelf Cracks.  In addition, BBC News has a video with the voice of David Vaughn, the leading scientist who predicted the collapse and began monitoring the bridge this past January.

How to Turn This News Event into an Inquiry-Based, Standards-Related Science Lesson

The Developing Student Understanding section of the Earth and Space Science standard of the National Science Education Standards states students should investigate the four major interacting components of the earth system: the geosphere, hydrosphere, biosphere and atmosphere. This story touches on all four, some more obviously than others.

In consideration of atmospheric influences, you can ask, Where does ice fit into the water cycle? What caused the bridge to crack?  In consideration of the hydrosphere, you can ask, What impact will that have on sea level? In consideration of the biosphere and geosphere, you can ask, How might a change in sea level affect living things? Available land mass? Existing coastlines?

You can also reinforce methods in and the nature of science. How did David Vaughn predict the bridge’s demise? How does this observation fit with other observations of ice shelves? What can scientists do with these observations? What good are they?

The following are some related teaching resources from the National Science Digital Library Middle School Portal: Science and the Polar Regions; What Goes Around Comes Around: The Water Cycle; Oceans, Climate and Weather; Beyond Penguins and Polar Bears: Weather and Climate; and Beyond Penguins and Polar Bears: Water, Ice and Snow

We Need Your Help

We want and need your ideas, suggestions, and observations. What would you like to know more about? What questions have your students asked? Do you have a favorite activity that you would like to share? We invite you to share with us and other readers by posting your comments. Please check back each week for our newest post or download the RSS feed for this blog. You can also request email notification when new content is posted (see right navigation bar).

Let us know what you think and tell us how we can serve you better. We want your feedback on all of the NSDL Middle School Portal science publications. Email us at msp@msteacher.org

An oxymoron? Perhaps, but 500 million years ago, such a creature roamed the vast seas. That was before the dinosaurs and concurrent with the Cambrian explosion. Scientists who put the fossil parts together described the giant shrimp this way:

. . . this underwater predator had a segmented body, a pair of claws and a circular mouth with several layers of overlapping teeth. Its distinguishing feature was a hard carapace that jutted out from its head, the function of which remains something of a mystery since it did not serve as a protective covering for its flesh. . . . With eyes to see and teeth to shred its prey, it would have dominated the food chain in a period when all animal life was underwater.

By “giant,” researchers mean perhaps twice the size of today’s average shrimp.

Globe Life, a Canadian online news source, has the story and illustration: New animal discovered by Canadian researcher. Well, granted the animal is not exactly “new,” the story of the discovery is intriguing from a science educator’s point of view. It amounts to one long puzzle completion exercise.

The fossil remains were found in the famous Burgess Shale region in the Western Canadian Rockies — at different periods in history, by different paleontologists, sent to different museums. However, one graduate student has put the pieces together and deduced the animal’s structure. Paleontologists explain what the giant shrimp tells us today:

. . . The discovery is important to . . . understanding of the development of arthropods, the group of animals with jointed legs that includes crustaceans, spiders and other insects. The segmented body of the hurdia, for example, is the feature that would have eventually developed into the arthropods’ limbs. Both during the Cambrian period and today, arthropods represent the biggest group of animals.

How to Turn This News Event into an Inquiry-Based, Standards-Related Science Lesson

Middle school students often have a good knowledge base regarding dinosaurs, but what do they know about the other life forms prior to that time on earth? The National Science Education Standards for life science suggest middle school students acquire knowledge of structure and function in living systems as well as diversity and adaptations of organisms. Concurrently students are expected to be developing their understanding about scientific inquiry. This story presents a wonderful opportunity to attend to these standards.

Show students the illustration. Ask, “What the heck is that? How big do you think it is? How can you tell?” You can’t, thus the need for inclusion of some kind of scale with illustrations. Alternatively, make copies of the illustration and cut them up into parts and pieces. Include some extraneous, irrelevant pieces. Have small groups of students piece it together, then share their product. How did they go about the process? How did they decide what is important and what is not?

Give them some more information. Tell them this creature is a crustacean and offer a little information about the group Arthropoda, such as — They have hard, exterior exoskeletons like a lobster or crayfish. They have segmented bodies, like an earth worm. Allow students to revise their product.

Share the story with students. Discuss the process: How long have scientists been working on this puzzle? How many different scientists contributed, from which countries? This underscores two aspects of the nature of science: (1) It is ongoing (As additional evidence is collected, theories get revised.).and (2) it is collaborative (Scientists build on the work of those before them.) In addition, science requires creative thinking.

What is a paleontologist and why are they interested in knowing everything they can about creatures 500 million years old? An excellent reader-friendly book on this topic of putting together evolutionary history pieces and why we care is Your Inner Fish by Neil Shubin. Reviews are available from Discover magazine at http://discovermagazine.com/2008/feb/your-inner-fish

The following are some resources from the National Science Digital Library Middle School Portal: Structure and Function in Living Systems; Geologic Time: Eons, Eras and Epochs; and Have You Seen an Arthropod Lately?

We Need Your Help

We want and need your ideas, suggestions, and observations. What would you like to know more about? What questions have your students asked? Do you have a favorite activity that you would like to share? We invite you to share with us and other readers by posting your comments. Please check back each week for our newest post or download the RSS feed for this blog. You can also request email notification when new content is posted (see right navigation bar).

Let us know what you think and tell us how we can serve you better. We want your feedback on all of the NSDL Middle School Portal science publications. Email us at msp@msteacher.org

If your classroom experiences are at all like some of mine, then you know the frustration of having students who either cannot or will not consider the relationship between their book knowledge and its applications in society. I provide what I consider to be scaffolded reading/thinking/discussion opportunities around current science issues connected to concepts learned in class. I’m sure I’m not the

ScienceDaily reports the California Academy of Sciences commissioned a telephone survey of over 1,000 American adults to test their basic science knowledge of things like what percent of Earth’s water is freshwater. Less than 1 percent of adults knew the answer–3 percent is freshwater. Despite their dismal performance, a large percentage of those surveyed agreed that science is important to society.

It does not require a master’s degree to grasp the seriousness of issues such as world hunger, epidemics, pollution, and lack of fresh drinking water. How can we expect a generation of scientifically illiterate citizens to create a sustainable, politically stable, healthy planet?

How to Turn This News Event into an Inquiry-Based, Standards-Related Science Lesson

The National Science Education Standards aim to provide a well-rounded science education for all students, hitting on all major science content areas, as well as the history and nature of science, scientific inquiry, and science in personal and social perspectives. Ideally, if students experience teaching according to the Standards, they should graduate with the desired knowledge, skills and attitudes necessary to participate in a democracy, enabling formation of sound policy and a sustainable, healthy planet.

I recently read an insightful article, Science Education in Three-Part Harmony: Balancing Conceptual, Epistemic, and Social Learning Goals, in which the history of science education is outlined; new information in the learning sciences and science studies is connected to science education; and the design of science curriculum, instruction, and assessment models is discussed. “Issues are raised about what constitutes the appropriate ‘grain size’ of ideas, evidence, information, and explanations for K-12 science . . . .” And there, I’m afraid, is the rub.

How do we strike a perfect balance between making sure our students acquire science facts and skills and making sure they can use those facts to discuss current science-related social problems in order to create and act on plans that begin to solve these problems? We have about 182 days. What topics and concepts do we choose? How long do we spend on it? In what sequence?

The article cites a National Research Council publication, Taking Science to School, in which research in K-8 education finds that science argumentation and discussion are sorely lacking in classrooms. The authors suggest that teachers facilitate student arguments relying on evidence obtained through rigorous investigations. This kind of experience presumably would enable students to grow into citizens capable of using evidence to make useful, informed decisions. It means students need to have a clear understanding of the nature of science and a sound understanding of some fundamental science concepts.

Science argumentation is a challenge for most teachers. Students often lack the social skills to conduct such arguments and are often trained in their other classes to express their feelings, opinions and emotions connected to an issue. While these human aspects cannot and should not be isolated from discussion of social issues, they cannot supersede scientific evidence. How many times have you asked students to propose a solution to a given observed problem, expecting them to employ recent class concepts, only to have them ask, “So you just want us to give our opinion?”

We have to keep shooting for the ideal balance; discuss with, communicate with, and make clear to our colleagues the approaches, goals and outcomes we now employ with the goal of increasing student science literacy.

The following are some resources from the National Science Digital Library Middle School Portal related to teaching and learning with scientific evidence: Ready, Set, Science: Putting Research to Work in K-8 Science Classrooms; What Killed the Dinosaurs? ; Pop Quiz; Why Did the Anasazi Abandon Mesa Verde? and When did the Grand Canyon Begin to Form?

We Need Your Help

We want and need your ideas, suggestions, and observations. What would you like to know more about? What questions have your students asked? Do you have a favorite activity that you would like to share? We invite you to share with us and other readers by posting your comments. Please check back each week for our newest post or download the RSS feed for this blog. You can also request email notification when new content is posted (see right navigation bar).

Let us know what you think and tell us how we can serve you better. We want your feedback on all of the NSDL Middle School Portal science publications. Email us at msp@msteacher.org

In his book Hot, Flat, and Crowded, Thomas Friedman challenges policymakers to assume strong leadership and create policies that will change cultures from ones of excessive, thoughtless waste to ones of thoughtful, integrated efficiency with a long-term vision of a sustainable planet. He presents numerous scenarios in which the alternative approach is not only in the best interest of the planet’s health but also brings about positive economic impacts.

This story from the NYTimes.com might be such an example: Many Plans to Curtail Use of Plastic Bags, but Not Much Action. The story describes how many municipalities have considered imposing fines or fees on plastic bags in order to curtail their use. These bags contribute to unsightly litter and are petrochemical products, meaning their manufacture — and their shipping — releases climate-warming compounds into the atmosphere.

As expected, the plastic-bag industry is opposed to such fees. Lobbyists insist the fees would raise the costs of products and, in the current economy, would hurt business. Referring to lawmakers’ reactions to the plastic-bag industry’s claims, Nathan Lott, executive director of the Virginia Conservation Network, said, ‘They’re not demanding a lot of evidence to prove it.” The news story does not investigate how such fees would impact people’s behaviors or the possibility of positive ripple effects the policy might send to the economy in giving rise to industries with a better alternative to plastic bags.

How to Turn This News Event into an Inquiry-Based, Standards-Related Science Lesson

Discussion of the role of policy in environmental issues as well as in personal decision-making is connected to the Science in Personal and Social Perspectives, content standards of the National Science Education Standards.

Ask students if they use plastic retail or grocery bags. Some may share that their families use canvas bags. What happens to the plastic bags after use? Have students ever seen plastic bags blowing around the roadside or flapping from a tree branch? Where else might the bags be, even if students have never seen them there? What are the bags made of? Are these bags a good thing for our environment? Are they good for anything/anyone?

Have students read the NYTimes.com article. Which side do they agree with most? Why? What kind of evidence would be appropriate in order to make an informed decision on this issue of fines for using plastic bags?

Is there another perspective that is not explicitly addressed? If plastic bags became “taboo,” what would people use instead? How would that alternative impact the economy? Industry? The environment? Would students be willing to pay a little more for products if it meant no more plastic bags in the waste stream? Why or why not?

Finally, ask if policymakers have a responsibility to address these kinds of issues, or should people just make their own personal decisions and trust good will triumph over evil?

To enrich your own understanding of how policymakers can influence the health of the planet, consider reading Friedman’s book. Here is a reading guide chock-full of provocative questions for discussion: http://www.thomaslfriedman.com/files/hot_flat_and_crowded_guide.pdf

The following are some related resources from the National Science Digital Library Middle School Portal: Global Change Instruction Program; State of the Nation’s Ecosystems; and What’s That Stuff? (click on “plastic bags” to go to http://pubs.acs.org/cen/whatstuff/stuff/8238plasticbags.html).

We Need Your Help

We want and need your ideas, suggestions, and observations. What would you like to know more about? What questions have your students asked? Do you have a favorite activity that you would like to share? We invite you to share with us and other readers by posting your comments. Please check back each week for our newest post or download the RSS feed for this blog. You can also request email notification when new content is posted (see right navigation bar).

Let us know what you think and tell us how we can serve you better. We want your feedback on all of the NSDL Middle School Portal science publications. Email us at msp@msteacher.org

I recently read The Omnivore’s Dilemma by Michael Pollan. One of the issues Pollan calls readers’ attention to is the meaning of “organic.” The U.S. Department of Agriculture appears to have a clear sense of what it means to be organic. See their web page on which 12 links to organic farming-related documents appear. Most consumers believe organic farming means no drugs or chemicals have been allowed to contact the animal or plant destined for the market. But Pollan argues that due to the pervasive use of pesticides, herbicides, and hormones, combined with the tendency to highly process foods, it is nearly impossible to bring “organic” food to market.

Even if a farmer avoids intentionally adding chemicals and drugs, they are so well entrenched in the environment that, due to ecological relationships, agricultural products cannot avoid them. Pollan further calls for transparency not only in what chemicals the food was grown with but also in the ways it is processed.

Speaking of transparency, the NYTimes.com recently published an interview with an Environmental Protection Agency (EPA) engineer who certifies household cleaning products as “green,” another ubiquitous, yet amorphous buzzword. In the interview, Clive Davies explains that if a manufacturer’s ingredients list is free from chemicals considered particularly harmful to the environment, it gets the EPA’s seal of approval. The EPA does not have a list of products that do not meet the standards, nor can the agency feasibly verify the submitted ingredient list.

How to Turn This News Event into an Inquiry-Based, Standards-Related Science Lesson

Discussion of the meaning of terms such as “organic” and “green,” “soap” and “detergent,” their ingredients, and impact on the environment is connected to the Science in Personal and Social Perspectives, Scientific Inquiry and Life Science content standards of the National Science Education Standards.

Ask students if they use soaps and detergents at home. What is the difference between a soap and a detergent? According to Kiwi Web: Chemistry and New Zealand, detergent is the evolutionary descendant of soap. That is, soap is plant-based and renewable and has been in use for thousands of years. In the early 1900s when soap was synthetically mass produced, largely from petrochemicals, it became a detergent.

Both soap and detergent are considered surfactants, which is a blended word for surface-active agent. The role of surfactants in detergents is to surround nonpolar substances like fats and oils and confer some polarity on them, so that water, a polar substance, can then adhere to the substances and wash them away.

What are these detergents made of? Many contain phosphate, though not as much as in the past. Phosphorus is a needed nutrient by all living things to build nucleic acids and ATP. Phosphorus usually is available in limited quantities in nature, and therefore limits population growth. Ask students where the detergents go after use. Down the drain and into the environment. What effect does the addition of phosphorous have on aquatic ecosystems? Algal blooms, which block light, increase the acidity of the water through production of CO₂ and carbonic acid, die, and decompose. This increases the bacteria/decomposer populations that consume available oxygen in respiration. This in turn negatively impacts almost all other species living in or near the area.

What is the effect of introducing surfactants to the environment? According to Davies, surfactants can stick to a fish’s gills and interfere with its ability to obtain oxygen through diffusion from the water. As you might imagine, surfactants can cause a negative ripple effect in the community.

What’s a “green” detergent? How would you know? Share the NYTimes.com story with the students. Allow them to critique it. What are the weaknesses in the story? What is not being said? Share a couple of reader responses with them, accessed by clicking on the link on the left side of the story page.

Consider having students conduct the suggested experiment — where they use progressively less laundry detergent and observe the effects. You could brainstorm variations such as a similar application to use of dishwasher detergent and shampoo.

Students can increase their scientific inquiry skills while learning some valuable consumer-related lessons.

The following are some related resources from the National Science Digital Library Middle School Portal: Chemistry: Making it Real; Stream Ecology; and SDA Kids Corner.

We Need Your Help

We want and need your ideas, suggestions, and observations. What would you like to know more about? What questions have your students asked? Do you have a favorite activity that you would like to share? We invite you to share with us and other readers by posting your comments. Please check back each week for our newest post or download the RSS feed for this blog. You can also request email notification when new content is posted (see right navigation bar).

Let us know what you think and tell us how we can serve you better. We want your feedback on all of the NSDL Middle School Portal science publications. Email us at msp@msteacher.org

Success stories in animal preservation are not very common. Since 1973 when the Endangered Species Act was passed, only 16 species of over 1,350 have been delisted. The whooping crane is not one of them, although its numbers have increased from 21 in 1941 to over 350 today. On February 22, 2009, the NYTimes.com published an extended story, Rescue Flight, centered on a unique group of hearty souls whose goal is to increase the whooping crane population.

The story is divided into six sections, toggling between (a) the group’s activities in a given day of whooping crane migration coaching, and (b) the history, ecology and biology of the bird. The story is filled with direct quotes from volunteers and biologists that create a comprehensive perspective on what saving a species entails.

Two powerful themes emerge. The first is: humans have drastically and permanently changed the landscape of the earth in irreversible ways. We cannot assume we have the ability to “undo” the situation we have created. There is a need to recognize that fact and to work for satisfactory alternatives that will enable survival of as many species and habitats as possible. The second theme follows from the first; that is, we may need to modify our concept of what it means to preserve a species.

For example, the story recounts how whooping cranes learn to migrate from other birds. So humans have engineered ways to act as bird facsimiles, which young whooping cranes emulate. However, after several years, the population has failed to become self-sufficient. Whooping cranes are completely reliant on human intervention for continued survival. One person is quoted in the story as suggesting that perhaps this is the greatest level of species conservation we can now hope for, given what humans have done to natural habitats around the world.

How to Turn This News Event into an Inquiry-Based, Standards-Related Science Lesson

Investigation of the Endangered Species Act opens a multitude of learning pathways aligned with the standards, from general to specific. The unit can focus on science and society, methods and technology in science (radio tracking, how to coach birds in migration), ecology and systems, or bird biology specifically.

Ask students what a whooping crane is. Consider cutting out a life-sized, five feet tall, paper silhouette by projecting this image from the appropriate distance: http://www.clker.com/cliparts/f/a/b/8/11954413771618148892molumen_whooping_crane_1.svg.hi.png. More images are available at http://www.fws.gov/endangered/

Explain that the bird has been on the endangered species list since the act passed in 1973, and that there are approximately 350 of them today living in Wisconsin and migrating to Florida in the winter. Is that a high number or low number? Why do they think so?

Consider putting students in six groups and giving each group one section of the story to read and highlight. Point out they don’t have the whole story, only a part. It is expected they will have some questions after reading their section. Have students articulate two to three questions they have about the whooping cranes as a result of reading their section.

Jigsaw the groups into new groups, so that each new group has at least one representative from each of the article’s sections. Students should then go around the group, each person sharing one of his or her questions. Groups should follow this with a sharing of a synopsis of their section, in order, 1-6, which should contribute to answering some of the questions.

At this point, you may want to have a large-group, guided discussion in which you articulate specific objectives and assist students in acquiring the relevant information and concepts. A few ideas for objectives are:

• Describe the efforts made and methods used to save the whooping crane from extinction.
• Convey the recent history of the species and its current status.
• Identify the flyway of the whooping crane and any potential obstacles along the way.
• Describe one behavior of the whooping crane that biologists are unable to explain at this point.
• Explain how species become endangered and whether this trend is reversible.

Finally, you should conduct some kind of assessment, either formal or informal, and give students an opportunity to reflect on what they have learned. You could ask them: “Which parts of the story/lesson are directly connected to you? Indirectly? Explain.”

The following are some related resources from the National Science Digital Library Middle School Portal: Populations and Ecosystems; One in Three Amphibian Species at Risk of Extinction; Polar Bear Central; and Extinction.

We Need Your Help

We want and need your ideas, suggestions, and observations. What would you like to know more about? What questions have your students asked? Do you have a favorite activity that you would like to share? We invite you to share with us and other readers by posting your comments. Please check back each week for our newest post or download the RSS feed for this blog. You can also request email notification when new content is posted (see right navigation bar).

Let us know what you think and tell us how we can serve you better. We want your feedback on all of the NSDL Middle School Portal science publications. Email us at msp@msteacher.org.

If you saw a newspaper or the news on TV at all last week, you must have heard about the catastrophic bushfires in southern Australia. Most were clustered 50 - 100 km northeast of Melbourne, capital city of the state of Victoria; yet there were other fires scattered across a wider area as well. The most recent stories from the British Broadcasting Corporation (BBC) report at least 200 persons died. Many more lost their homes and are displaced. The recent reports also state that the person suspected of arson in starting some of the fires has been arrested.

Of course wildlife was impacted as well. Australia has a number of unique species, many of which are endangered, including Koala. One blogger reports over a million native animals have died. Its is difficult to say if and when the environment will recover, given the current drought.

So why should we care? It’s half a world away and it was a freak accident, after all. Not so fast. Some recognize the fires as part of a trend of more severe weather events associated with climate change. The same BBC story that reported on the death toll in the Australian bushfires also reported severe flooding in New South Wales and Queensland, shutting down thoroughfares and isolating towns.

How to Turn This News Event into an Inquiry-Based, Standards-Related Science Lesson

Did your students hear news reports about the Australian bushfires and see some of the associated pictures? If not, you can access a variety of related stories from http://news.bbc.co.uk/2/hi/asia-pacific/7894011.stm. What are your students’ reactions? Ask for their thoughts: Are the fires likely to recur or was this an isolated event? What accounts for the ferocity of these fires as compared to all others before them?

How about the early February tornadoes in Oklahoma — the most severe in the state’s history? Is that another isolated event, or part of an emerging trend?

What is the relationship between climate change and weather events? This is a good opportunity to help students discriminate between weather and climate, while developing a sense of their relatedness. The following resources from the National Science Digital Library Middle School Portal will be helpful: Oceans, Climate and Weather; El Niño and His Sister La Niña; Polar Bears and Climate Change; and The Powerful Punch of a Hurricane.

>

We Need Your Help

We want and need your ideas, suggestions, and observations. What would you like to know more about? What questions have your students asked? Do you have a favorite activity that you would like to share? We invite you to share with us and other readers by posting your comments. Please check back each week for our newest post or download the RSS feed for this blog. You can also request email notification when new content is posted (see right navigation bar).

Let us know what you think and tell us how we can serve you better. We want your feedback on all of the NSDL Middle School Portal science publications. Email us at msp@msteacher.org.

According to TV’s CSI, forensic science can do no wrong. Thus, if you are a criminal, wear gloves and a hairnet, brush over footprints left in the dirt, and leave no evidence behind.

Remember the O.J. Simpson trial for the murder of Nicole Brown? It appears the police botched the evidence collection, calling the investigation into question. How many times have you seen your local paper run a story about a person who was wrongly convicted and later freed from prison based on new DNA evidence?

The NYTimes.com reports that the National Academy of Sciences will release a study this month documenting shoddy forensic techniques across the country’s law enforcement agencies. Further, forensic witnesses tend to exaggerate evidence at trials. The report calls for better training of technicians, national standards, and independence of forensic investigations from law enforcement agencies.

The report puts law enforcement agencies, including the FBI, on the defense. But everyone who has been wrongfully convicted and everyone else who has the potential for such an experience should welcome the report. Understandably, defense lawyers are big supporters too.

How to Turn This News Event into an Inquiry-Based, Standards-Related Science Lesson

Forensic science seems to be inherently interesting to students. They love the mystery, and the good versus evil theme. But do they realize the full scope of disciplines involved in this field? The article lists “anthropology, biology, chemistry, physics, medicine and law.” This is a good opportunity to introduce middle school students, who are just beginning their understanding of what science is, to the various science disciplines and to see applications of the scientific way of knowing in fields like law.

Put students in teams and have them look up each of these fields. After they learn from each other what each field is about, present them with a crime scenario. There are several to choose from at http://www.colorado.edu/Outreach/BSI/k12activities/forensics.html. How would each discipline play into investigating such a crime? How will we know the investigation is rigorous and executed according to methods in science?

If appropriate, have students work in cross-disciplinary teams, representing the fields listed above, to investigate the crime. Create a rubric for students that emphasizes methods in science. Criteria should include:

Finally, help students make explicit connections between the investigation process and methods in science. For example, though the rubric may not have required students to make a hypothesis, the point in the investigation when students thought, “OK, if John Doe committed this crime, then X,” represents hypothesizing.

According to the National Academy of Sciences, America needs well-trained forensic scientists. Their training can begin now with getting a good handle on what scientific investigations require and the teamwork needed to execute them. Training students in scientific thinking will serve them well for the rest of their academic career and beyond.

Here are additional resources from the National Science Digital Library Middle School Portal: Genetics, (a tutorial including a section on forensics); DNA Interactive Applications: Science Sampler: Forensic Measures, and The Evaluation of Forensic DNA Evidence

We Need Your Help

We want and need your ideas, suggestions, and observations. What would you like to know more about? What questions have your students asked? Do you have a favorite activity that you would like to share? We invite you to share with us and other readers by posting your comments. Please check back each week for our newest post or download the RSS feed for this blog. You can also request email notification when new content is posted (see right navigation bar).

Let us know what you think and tell us how we can serve you better. We want your feedback on all of the NSDL Middle School Portal science publications. Email us at msp@msteacher.org.

What do your students know about the food of the gods, chocolate? Do they know it is extracted from a plant? Do they know where the plant occurs naturally, how it is cultivated, or processed? Do they realize the scope of the chocolate industry worldwide? What news stories relating chocolate to health are valid? Why should students care?

As Valentine’s Day approaches, let chocolate serve as a sure-fire hook connecting to a number of science topics and lessons. Studying ecology? Why not research the ecology of Theobroma cacao? Studying physical and chemical change? Melting chocolate and baking brownies couldn’t be better examples!

How about a science and society mini-unit focused on the chocolate industry — who it employs, how many, where, doing what, producing what products? Interested in investigating how human activities impact the environment? The chocolate industry can be the focus.

Doing a health and nutrition unit? What is chocolate composed of? What nutrients are in chocolate? Does chocolate cause acne? Obesity? Heart disease? Hyperactivity?

How to Turn This into an Inquiry-Based, Standards-Related Science Lesson

Physical Appearance and Anatomy of Theobroma cacao

Ask students where chocolate comes from. This may stump some, while others may know it comes from a plant. Can they imagine what the plant looks like? A tree? How big? What do the leaves look like? The fruit? A series of progressively deductive photos is found at http://www.delange.org/Cocao/Cocao.htm. The page starts with photos of entire trees and funnels down to the fruit and seeds. Students can get a good concept of the physical appearance of the plant. Other image sources are the U.S. Department of Agriculture (http://plants.usda.gov/java/profile?symbol=THCA) and the U.S. Geological Survey (http://images.nbii.gov/details.php?id=65317&cat=Fruit%20Trees).

If you have had some discussions of adaptations as related to biomes, have students infer the biome in which this tree occurs based on the apparent adaptations of its leaves, tree size, habit and/or fruit size. Can students infer the methods of pollination from this photo: http://www.botany.org/plantimages/ImageData.asp?IDN=07-006h&IS=700?

Fact Sheets

The first fact sheet was published by the Australian government and is very scientific, describing the taxonomy and distribution of the cacao tree. The second fact sheet is aimed at consumers. It describes what antioxidants and flavinols are and their health benefits.

http://www.nt.gov.au/d/Content/File/p/Fruit/FF3_cocoa.pdf

http://www.aging.state.pa.us/aging/lib/aging/2008_NC_Cocoa_Fact_Sheet.pdf

How Is Chocolate Processed?

This page from the Hershey Company gives both a print and a video version of the processing of chocolate. The video starts with images of T. cacao being harvested and then moves to the factory at Hershey, Pennsylvania. The following lesson from the Field Museum appears to be a good match for the video: http://www.fieldmuseum.org/CHOCOLATE/education_pdf/cc_lesson5.pdf

Exploratorium provides images and the history of chocolate, spanning from the Amazon and prehistoric American tribes who apparently ”invented” chocolate all the way to current scientific findings related to the health benefits of chocolate.

You can purchase raw or roasted beans and nibs (broken pieces of seed) from http://livesuperfoods.com/cacao.html to show students various stages of the chocolate-making process.

Research Projects

This press release from the U.S. Department of Agriculture identifies some fungal diseases that infect Theobroma cacao and explains why sequencing the tree’s genome will help in preventing infections. In addition, there are links to three related stories.

Miscellanea

Does chocolate cause acne? Every teenager is interested in this question and will be no doubt pleased when they read this short article from Indiana University School of Medicine: http://soundmedicine.iu.edu/archive/2002/mystery/acneChocolate.html

According to the Cleveland Clinic, chocolate may be helpful for those with heart disease: http://my.clevelandclinic.org/heart/prevention/nutrition/chocolate.aspx

Here’s an additional resource from the National Science Digital Library Middle School Portal: Chocolate Exhibition.

We Need Your Help

We want and need your ideas, suggestions, and observations. What would you like to know more about? What questions have your students asked? Do you have a favorite activity that you would like to share? We invite you to share with us and other readers by posting your comments. Please check back each week for our newest post or download the RSS feed for this blog. You can also request email notification when new content is posted (see right navigation bar).

Let us know what you think and tell us how we can serve you better. We want your feedback on all of the NSDL Middle School Portal science publications. Email us at msp@msteacher.org.

When you conjure up an image of cells, what do you see? What do you think? You may see a snapshot of an animal tissue, perhaps with actively dividing cells. That’s understandable because, as animals ourselves, we’re aware that cells come from other cells, thus the need to undergo mitosis, or cell division, frequently.

But one kind of mammalian animal cell does not fit that image—nerve cells. They do not arrange themselves as cells in a typical tissue do. Nerve cells are singular, with a long, sometimes very long, threadlike extension called an axon. And they don’t undergo mitosis frequently, except in embryos. This apparent aberration in the world of cells has puzzled scientists and medical researchers. If one could get nerve cells to behave more like other cells in terms of regeneration, a host of nerve-related diseases and damage could be reversed.

ScienceDaily published a story on January 26, 2009, reporting on exactly that kind of breakthrough, New Hope For Restoring Injured Nerves. A group of researchers at the University of Utah uncovered a pathway (a chain of molecular events) involving a gene that, when forced to be overactive, leads to repair of severed nerve cells in nematode worms. The gene is also found in mammalian genomes; thus, the researchers predict they will be able to replicate the study in mammals.

Finding a gene that produces a protein that aids in nerve cell repair in worms is not surprising. Gene theory predicts just that in organisms known to regenerate portions of their anatomy. It also is not necessarily surprising to find the same gene in mammalian systems, since evolutionary theory reveals our common ancestry. What did surprise researchers was that the pathway that results in nerve cell regeneration is not found in developing embryos.

Scientists have puzzled over the fact that nerve cells are regenerated in mammalian embryos and very young, rapidly developing mammals, but not in adults. The question was, what did mammals lose along the way to maturity? The pathway discovered in the new study “is unique in that it is not used by the nervous system during normal embryo development, yet it is absolutely required for regeneration,” one of the researchers said.

How to Turn This News Event into an Inquiry-Based, Standards-Related Science Lesson

Middle school curriculum usually includes some study of cells, genetics, and body systems. This story provides background for some authentic discussions allowing students to apply and extend their knowledge in these three areas. At the same time, it provides opportunity to reinforce concepts in methods of science.

Ask students what happens to a worm that gets cut in half by a gardener’s shovel? To a starfish whose leg is bitten off by a predator? What is regeneration? Have they ever wondered why humans cannot do the same? Do they know that mammalian embryos and very young mammals do have the ability to regenerate? How might regeneration be related to the science of genes? What does the idea of regeneration have to do with curing paralysis in humans?

Remind students of cell theory and show them some visuals of cells, and cells in tissues, organs, and systems. Show them some nerve cells. If they’ve studied the nervous system, they already have some notions regarding nerve cell structure and function. Explain that in paralysis, the nerve is severed and, in adults, not easily repaired.

Point out that scientists have uncovered the worms’ pathway that enables their nerve cells to regenerate. Ask how such a discovery could possibly be useful in mammalian systems? Remind students that all living things share some common characteristics, like cellular structure, DNA, and the ability to respond to stimuli. Is it possible that mammalian genomes could contain the same or similar genes that enable regeneration in worms? As predicted by evolutionary theory, the answer is yes!

So why can’t we regenerate nerve cells? Remind students, or explain, that genes have to be turned on in order to produce the necessary proteins that participate in a pathway culminating in regeneration. In this study, scientists methodically “knocked out” genes, one by one, in worms until they found the one primarily responsible for nerve cell regeneration. (There actually are four genes working together.) When the scientists created conditions that enabled the gene to increase its activity, producing ample protein associated with regeneration, nerve cell regeneration was rapid in adult worms. This confirmed their hypothesis regarding the activity of a particular gene on regeneration. It also enabled them to uncover the steps in the pathway from gene to cell regeneration. Knowing the steps allows scientists to hypothesize possible ways to enhance the pathway in order to induce regeneration in mammals.

Using this story allows you to facilitate student synthesis of knowledge from perhaps three different units in their curriculum around three fundamental theories: cell theory, gene theory and evolutionary theory. It also reinforces concepts associated with the Life Science content standard of the National Science Education Standards, as well as the History and Nature of Science content standard.

Here are additional resources from the National Science Digital Library Middle School Portal:Visit Cell City; Middle School Meets Evolution; Cell Differentiation; and Cell Biology Animation

We Need Your Help

We want and need your ideas, suggestions, and observations. What would you like to know more about? What questions have your students asked? Do you have a favorite activity that you would like to share? We invite you to share with us and other readers by posting your comments. Please check back each week for our newest post or download the RSS feed for this blog. You can also request email notification when new content is posted (see right navigation bar).

Let us know what you think and tell us how we can serve you better. We want your feedback on all of the NSDL Middle School Portal science publications. Email us at msp@msteacher.org.