A Gentle Reminder

If you were one of the students who did not take the quiz on Monday or Tuesday before Thanksgiving, you'll need to take it as soon as we get back to school.  Please be prepared to take the quiz during lunch on Monday or Wednesday.  Thank you!

Jokes About Viruses and Bacteria

Happy Thanksgiving!  After you remember to be thankful for enzymes, here are a few jokes you can tell around the dinner table:

It's Time for a Quiz!

The 7th and 8th graders are having a quiz on viruses and bacteria on Monday 11/23/09 and Tuesday 11/24/09.  Anyone who's absent can take it when we return from Thanksgiving break.  Here's a copy of the Review Sheet:

VIRUSES

What is it? (definition)

Is a virus living?  Why not?

Origins of viruses (their evolution)

How a virus invades a cell

How a virus reproduces

How a vaccine works

The two ways in which antibodies can help fight against a viral infection

How a white blood cell helps in the fight against a viral infection

 

BACTERIA

What is it? (definition)

How  bacteria reproduce (duplicates all of its parts and splits into two.  This is called FISSION)

Ecological roles of bacteria:

• nitrogen fixers

• other bacteria involved in the nitrogen cycle

• decomposers (produce ammonia!)

• photosynthesizers

• Inside the bodies of animals, where they help digest food, make vitamins, 

and perform other vital functions.

• Some bacteria infect other living things and cause disease.

 

NITROGEN

Why is it important to living things?

Why are most of the world’s living things dependent on bacteria for nitrogen?

What happens to nitrogen when we say it is “fixed”?

What is a “nitrogen-fixing plant”?

Which nitrogen compounds are easily taken up by plants?

Why are we once again in awe of enzymes?

The World of Microbes

This past week in science class, we have been learning about the world of the tiny and the world of the very, very tiny. With students, teachers and the general public concerned about infection by the H1N1 virus, it seems to be a good time to begin our study of microbes. There is a very important link between bacteria and plants, but we'll explore that later. For now, we've been looking at the scale of microbes, i.e. their relative size, primarily through this ultra-cool website Cell Size and Scale. We've also been learning about differences between viruses and bacteria, specifically examining how viruses invade and reproduce in one's body. A video produced by National Public Radio has done a fantastic job depicting this process; it can be found on the site Flu Attack! How a Virus Invades Your Body. And finally, everyone got a big kick out of these suggestions on alternative greetings during the flu season: Don't Gimme Five!

Classification of Living Things

     

            Indian mongoose

         Herpestes javanicus 

In addition to working on their plant experiments last month, students studied the classification of living things. They learned how to use the taxonomic ranking system through a classification activity designed around the University of Michigan Museum of Zoology's Animal Diversity Web, a phenomenally rich website devoted to providing an "online database of animal natural history, distribution, classification, and conservation biology". Many students wanted to continue exploring these topics at home; click on the link if you're interested in doing so!

For the activity, students were asked to use to website to list the taxonomic ranks,  first for four assigned and closely related animals (Indian Mongoose, striped-necked mongoose, meerkat and pygmy spotted skunk), then for four closely related animals of their own choosing. The requirements for the second four were that two be of the same genus, three be of the same family, and all four be in the same order.  The students tackled this task with enthusiasm, and this was reflected in the high quality of their work!  The assignment not only exposed them to the construction of classification systems, but also provided an understanding of how the shared evolutionary history of different species can be examined through their classification. 

Open for Science is Open Again!

Hello and welcome to the 2009-2010 school year at Ann Arbor Open! The Open for Science blog is now officially revived!

During these first two months of 7th and 8th Grade Science, we have been learning about photosynthesis and practicing the scientific method by conducting experiments on plant growth in the Ann Arbor Open School garden. Specifically, the students planted ryegrass, Lolium spp., a winter cover crop commonly sown by farmers in Michigan. They varied one factor between two rows to see if ryegrass growth, measured in centimeters, would be affected. The students

based their hypotheses upon their knowledge of photosynthesis, and they designed a range of interesting and solid experiments where plant growth was the dependent variable and factors such as light level, water amount, addition of fish emulsion, presence of vitamin C, paprika or calcium in the soil, or the addition of glucose or salt to the water were the independent variables. The students diligently followed their plants' progress and took their last measurements around October 14, and they have been writing up their reports ever since, working on data analysis and interpretation.

This past week, the students have been learning about the null hypothesis * and its relevance to making decisions about interpreting results. The students have been happy to hear from me and several other adults, among them practicing biologists and social scientists, that learning what the null hypothesis is at the age of 12 or 13 will save them potentially weeks of trying to wrap their minds around this concept in college! Adolescent minds are so much more flexible in their learning, and the students' ability to incorporate the concept of the null hypothesis into their array of tools for the analysis of scientific observations is inspiring!

As we learned about plants and the scientific method, we were appropriately awestruck by the existence of photosynthetic slugs and predatory fungi. If you click on the highlighted links, you might be equally amazed by these creatures who surprise us by crossing the boundaries of our expectations for slugs and fungi!

* this link is to a very good and very funny description of the null hypothesis. Here's an excerpt: "Usually, the null hypothesis is boring and the alternative hypothesis is interesting. Finding that male chickens have bigger feet than female chickens might lead to all kinds of exciting discoveries about developmental biology, endocrine physiology, or sexual selection in chickens. Finding that male and female chickens have the same size feet wouldn't lead to anything except a boring paper in the world's most obscure chicken journal."

Happy Earth Day!

Welcome to Open for Science, the classroom blog for Ann Arbor Open School's 7th and 8th grade science class. This is a cyberplace for you to learn about what we're doing in science class, to catch up on our activities, to check for upcoming assignments, and to get a glimpse of all the fun we're having!

We are currently in the middle of our electricity and sustainable energy unit. Electricity is a stream of electrons, and this has been exciting for the students to contemplate, given that we have spent much of this past year learning about the structure and behavior of atoms. It's fascinating to consider how humans have been able to develop technologies to channel electrons through wires and to access the moving electrons' energy. Since the production of electrical energy requires an input of some other energy form, such as thermal, mechanical, chemical, light or nuclear, humanity's next step is to refine our capacity to use and produce energy sustainably.

More to come soon, but in the meantime, here's a wonderful short video on wind energy which students saw in science class recently. (The video was submitted to me as part of a student's science project - thanks, N.!)

And Happy Earth Day!