Sunday, October 2, 2016

Homeschool Science: Shark Dissection, and our Sharks Science Study

Back in the summer, partly as a bit of thematically-relevant prep for the kids' trip to California and partly just on a whim, I signed the kids and I up for a free MOOC on sharks and global biodiversity through EdX.

Y'all, this course changed our lives.

One week in, and Will was already telling me that she wants to be a marine biologist when she grows up (considering that her next most recent dream job was global dictator, this is for sure a step in the right direction). Two weeks in, and I knew that I was going to be turning this MOOC into a more extensive study, based on how passionate the kids were about it.

Over two months in, and we've just finished that more extensive study, and we're also now completely obsessed with sharks, so much so that I altered our road trip plans to include some shark-related sites.

We did this MOOC live, with everybody participating at their own pace, and for our recent study we used it again as our spine. Instead of going through the entire course again, I gave the kids specific units from specific weeks, tied to enrichment activities to deepen their understanding of shark biology and to contextualize it with human biology.

We memorized the layers of the ocean, for instance, and the types of shark habitats, with the kids creating a giant poster of this and then putting pictures of sharks on it where they live.

We memorized the external anatomy of the shark, particularly all the types of shark caudal fins.

We conducted a comparative anatomy of the shark's internal organs, including some hands-on experimentation with osmosis and the functioning of a shark's oily liver, and comparisons between the human brain and the shark brain, the human heart and the shark heart, and the human respiratory system and the shark respiratory system.

We discussed pop culture representations of sharks, watching Jaws as our main resource for this (although I really should find a copy of Sharknado for us to watch next...), the conservation of sharks and their use in aquariums (with lots of webcams and a planned visit to the New England Aquarium this month!), and how to stay shark safe in the ocean, practicing shark-safe techniques one afternoon at the lake.

The long-anticipated culminating activity of this sharks study was a dissection of an actual shark, the squalus acanthus, or common dogfish. The dogfish shark is bought by science suppliers from fishing by-catch, and our purchase of it first involved a lot of discussion with the kids in which I made clear my reservations about using animals in science but also admitted what educational experiences they would gain from it. The kids did decide that they wanted the experience of dissecting a real animal, and promised that they would treat the shark's corpse respectfully throughout, which they did.

We will revisit the use of animals in our science studies on a case-by-case basis.

We split up our complete shark dissection into four separate sessions--Home Science Tools, where I purchased the shark, assured me that I would be able to re-seal the shark into its bag between sessions, but at the beginning of the fourth session, I noticed that the shark was getting moldy and told the kids that we had to finish up the rest of our dissection on that day. In retrospect, I should have stored it in its bag and in the refrigerator, but who really wants a bagged shark corpse sitting next to the pasta salad?

Funnily, since this was a shark dissection, the session that the kids seemed to enjoy the most was the one on external anatomy. They had a fabulous time finding all of the external features of the shark, poking at them a bit, and photographing them for posterity. Our USB microscope was crucial for this, and I don't know how we could have done the dissection without it:

a view inside the nares
electroreceptors known as the ampullae of lorenzini

examining the cornea
gill slits 
examining the caudal fin

Home Science Tools provided a brochure on shark dissection, but we vastly preferred The Photomanual and Dissection Guide of the Shark, which is far more informative, although you have to skip around in it in order to conduct an orderly dissection. It's best to consult several sources, I learned, so I also used a few more books from our local university library as reference, as well as several Youtube videos of variable quality.

And here we are finally cutting our shark open!

The cartilage is hard to cut through, so I helped some, but I wanted the kids to do most of the work themselves:

Frankly, I was completely over this shark dissection halfway through our exploration of the shark's stomach contents--fish spines, a gill system, couple of shells, lots of scales and slime.
See those stomach contents? Shudder.
 But I put on my game face and we sailed through the circulatory system--

--the respiratory system--

 --and the skeletal system.

This dissection was hard for me to get through, although I didn't let the kids know it. I'd given them my objections, they'd made an informed decision to do the dissection anyway, and what they needed to do it properly was a guide and mentor, not a moaning sicky-face. To be fair, though, I did take the rest of the day off after this, and I 100% left the clean-up to them while I took a hot shower, then lounged in my bed with a glass of wine and a good book.

Overall, this sharks unit was a terrific science study. We had a good spine, were able to use lots of supporting resources, conducted plenty of interesting hands-on activities, and are able to extend our study with a couple of detours on our upcoming road trip. The kids have always loved science, and always loved animals, but we've now discovered that they also very much love animal biology. Next semester, we're going to try another EdX course, this one on animal behavior, although my plan is to review it myself first so that I can incorporate enrichment activities the first time around.

And we might end up dissecting a sheep's brain...

Here are some other resources that we enjoyed during this sharks unit:

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