Teach.Genetics has a bunch of “Print and Go” pdf lessons on their site, but also have a really neat interactive page where you can look inside an animal cell. What’s really neat about this flash app is that you can move around a little, round window as you scan through the cell membrane. You can also take the membrane away to see everything inside the cell at once, but that takes away the challenge.
When you use the little window you have to piece together what everything inside the cell looks like by memory. For a student new to the parts of a cell this might be a bit of cognitive overload, but once your somewhat familiar with the pieces, this makes for an interesting challenge.
The Teach.Genetics site and materials are free for educational use.
The message — that babies and parenting are hard work — seems to be sinking in for some of its intended audience. [15 year olds] Leslie, Miguel and Paola all intend to be parents, but, as Miguel says, “not at this age.” – Grigsby Bates, 2010.
NPR’s Morning Edition had a story on “Teen Mom” and “16 and Pregnant”, two TV shows from MTV. These shows apparently offer a very realistic take on what it means to be a teen parent. So much so, the Kaiser Family Foundation is providing free DVD’s of the 16 and Pregnant series (as well as the Think HIV: This Is Me documentary).
I have not seen either of these series, but am interested in finding out if any of my students are familiar with them, if they’re appropriate for early adolescents, and if anyone else has tried them. From the radio program it sounds like they might be a useful supplement to the Baby Think It Over® infant simulators.
On a somewhat tangential note, every time is see the Baby Think It Over dolls, I’m reminded of Elna Baker’s story, Babies Buying Babies (see Act 3), on This American Life. It’s about the choices parents make when choosing the race of a life-like, newborn doll for their kids. The Baby Think It Over dolls are pretty life-like and I’ve heard anecdotes of kids getting strange looks when walking around, not just with a baby, but one that looks like it’s from a different race.
Dealing with genetic traits and family trees can be kind of tricky sometimes, particularly with early adolescents who are still learning about personal boundaries and have the potential for sharing too much information. One alternative to delving too deeply into personal family histories is to stress the less invasive traits. Anna Clark has had some success (and the students liked it) using the Handy Family Tree, from the University of Utah’s Teach.Genetics website.
John Wyndham's The Crysalids. (via Powell's Books).
I also discuss some of the thornier issues when we do the John Wyndham book, The Chrysalids. It can be an uncomfortable book, but has the emotional separation of fiction.
Teach.Genetics is a great resource. They have a number of “Teach and Go” exercises like this one, and some interesting interactive applications. I’ll post more as I browse more through their website.
Extracting pectin for making jelly does not seem to be that hard. Sam Thayer has a nice little article on how to get pectin from apples. The blog Spain in Iowa, has some nice pictures and video of how they extracted pectin from apples and what the result should look like when you test it by putting a teaspoon of pectin into a teaspoon of rubbing alcohol. Almost immediately (but leave it in for a minute), the pectin should jell in the rubbing alcohol and you should be able to pull it out using a fork.
Basically, all you do is chop up the apples, cook them for a long time over low heat till they’re broken down, and then strain out the liquid produced. Since I have access to a lot of green apples that won’t be used for anything else, I tried the process myself. Using a pot full of apples I produced a lot of liquid; way more than I could ever use, but the process seems to work fairly well.
One 8 quart pot of apples produced 8.75 cups of liquid. I’d planned to use the home-made pectin in my currant jam, but testing the currant juice showed that it had just as much, if not more pectin than my boiled apple residue. I guess I’ll save the apple pectin for future use.
Ideally, Student Run Businesses should sell goods or services that are worth the value paid. While I appreciate that there is some value to the sympathy of friends and family, it is nice when customers believe they’re getting a good deal even without that. One direction I try to direct the students is toward making things from scratch, because it adds so much to the experience. Then they can have the extra value of using natural, perhaps even organic, ingredients and satisfying Michael Pollan’s rules for good eating.
In Defence of Food by Michael Pollan
My students have not yet tried jam or jelly-making, but if they do natural pectin would be great.
I’d like to minimize the sugar content of the jam in order to see the most of the currant’s tartness. According to the FAO, you need to have about 60% sugar concentration in the final jam for good preservation. I’ve squeezed the currants and produced quite a bit of juice. I need to find out how much sugar to add.
To figure out how much sugar we need to add, based on the mass, we need to define our terms. Let’s say the amount of sugar is s, the amount of jam is j and the total mass, the sugar plus the jam, is t.
So the total mass is going to be:
(1) t = s + j
Since the amount of sugar needs to be 60% then:
(2) s = 0.6 t
If we substitute the first equation (1) into the second (2) we’ll have just one equation we can solve to find the amount of sugar:
(3) s = 0.6 (s + j)
Now we solve for the amount of sugar, s. Start by expanding the right hand side of the equation (distributive property):
(4) s = 0.6 s + 0.6 j
Next, isolate s on the left hand side of the equation by subtracting:
(5) s – 0.6 s= 0.6 s + 0.6 j – 0.6 s
Which gives:
(6) 0.4 s= 0.6 j
Now, get rid of the coefficient on the left hand side by dividing through:
(7) 0.4 s / 0.4 = 0.6 j / 0.4
To get:
(8) s = 1.5 j
So to have the right amount of sugar, I need to add one and one half times as much sugar as I have juice. So, if I have 2.0 kg of juice, then:
s = 1.5 (2.0 kg) s = 3.0 kg
3.0 kg of sugar is a lot of sugar! However, if we boil the jam, some of the water in the juice will evaporate. Therefore, if we know how much sugar we want to add in we should be able to calculate how we need to evaporate to get the right ratio. More evaporation should also lead to a more concentrated flavors in the jam. Hmmm …
Boiling jam will often create a froth that floats on top, much like the granitic continental crust floats on the Earth’s mantle. Also like the boiling jam, the mantle convects (even though the mantle is not liquid).
Convection in jam.
The darker red areas in the image are where the convection cells in the boiling jam reach the surface and push the froth away. It’s a bit like the bulge in the Earth’s crust that occurs beneath hot-spots and the mid-ocean ridges.
Model of convection in the Earth's mantle (image from Wikipedia)
I’m thinking that the Creating Coacervates lab, the only one on the origin of life section, might fit into my orientation cycle plans. Coacervates are small, microscopic blobs of fat (lipids) that look like, and have many of the same properties as cells, amoebas in particular. They can be produced with simple chemicals. One of the key things I’d like to start the year with, is the idea that:
complex life-like cell-like structures can be produced naturally from simple materials with simple changes. Flammer, 1999.
These abiotic blobs can be compared to the protozoans in a water droplet sample while we learn how to use the microscopes. It also ties into the Miller–Urey experiments that produced amino acids using electricity and simple compounds: water, methane, ammonia and hydrogen gas. The Miller-Urey experiments will pop up later when we read Frankenstein.
Mortar shells landing on concrete create a pattern almost like a floral arrangement. In Sarajevo, after the Bosnian War, the mortar scars in the sidewalks were filled in with red resin. The results are called Sarajevo Roses.
Flickr has a nice map that links to Rose pictures in downtown Sarajevo.
I found out about these from reading a recent set of View From Your Window Contest entries on Andrew Sullivan’s blog.
