Molar Mass of Molecules

Calculate the molar mass of a molecule:

The notation for the chemical formula is a little funky: you put the element symbol and then the number of atoms separated by a colon; each element/number of atoms pair are separated by commas, so sodium chloride (NaCl) would be “Na:1,Cl:1“.

This will have to do until I can write something to parse the regular chemical formula notation.

On the plus side, you can link to a specific molecular mass calculation by adding the formula to the url. So magnesium chloride (MgCl2) can be found with this url:

https://soriki.com/js/chem/chem_db/molecular_mass.html?formula=Mg:1,Cl:2

She’s got (a) heart: Duck Dissection

Heart in hand: a duck's heart to be precise.
Heart in hand: a duck’s heart to be precise.

Dissection time is always interesting in the middle school classroom. Some kids start off a little squeamish, but there are always a few who pitch right in. All of the class were working on different organisms–microscopic algae (desmids), insects, plants, etc.–but I set up the dissection table in the middle of the room. With all the other tables facing inwards, everyone who wanted to got a chance to see the internal organs as they were carefully, but triumphantly, traced and extracted. It spreads the enthusiasm, and gives the other students a heads up as to what will be expected.

One student brought in a duck that her father had shot. She was familiar with cleaning hunted fowl, so had no qualms about the dissection. The duck was a great specimen, because the internal organs were large and easy to identify.

Duck dissection.
C.F. leads the duck dissection.

She, and most of the rest of the class, had dissected a sheep’s heart in elementary school. This time, however, they got to see how the heart was connected to the rest of the body. We got to talk about why smaller organisms, like ducks, could get away with two chambered hearts, while larger ones need four chambers.

Indeed, the tracing of the artery leading out of the heart lead us to compare of the color of the duck’s lungs–so red they were almost black–and the fish’s gills, which were also a deep red. And that, in turn lead to a discussion of how organisms ingest the gasses they need to survive: microbes through diffusion; insects through spiracles and trachea; mammals through lungs. Tomorrow we’ll talk about how the surface area to volume ratio changes with size.

Peer Teaching

Ms. R. helps a peer with her experiment.
Ms. R. helps a peer with her experiment.

Half the Chemistry class was gone yesterday, so they had to make up their experiment today. Well, one student of the students who did her work yesterday entreated me to lead her peers through the experiment. It was pretty awesome, because she had been struggling with the topic for the last week and had finally gotten it yesterday.

And she did an excellent job. She not only walked the rest of the class through the theoretical calculations, but guided them through the experiment itself.

Peer teaching works best when students are excited about what they’ve learned and want to share. I’m still trying to figure out the best way of inciting this excitement when I break the groups up for their projects. Giving them choice is important, but also, I think, giving them challenging work that they’re proud to accomplish.

Devices

I tend to let my students have a lot of freedom to use their myriad technological devices as they will. Just as long as they use them responsibly (i.e. for academics during class time). What’s most interesting these days is seeing how they combine the various electronics.

Working with pen, paper, tablet and laptop.
Working with pen, paper, tablet and laptop.

This Chemistry student is referring to her textbook on the iPad, while she creates a presentation on her laptop. Yet pen and paper are still integral parts of the process.

Talk Timer

Arduino timer.
Arduino timer.

Given the idea that “learning situated in meaningful contexts is often deeper and richer than learning in abstract contexts,” (Lillard, 2007), I’ve been trying to orient our robotics program toward developing devices that we can use at school. Not only can these devices serve a useful purpose, but their presence around the school can, perhaps, inspire other students to want to make their own.

To this end, one of our first practical projects is a timer (by Joe A.) for when students give their presentations in Chemistry class. For the last round of presentations they had 20 minutes, so I had Joe build the circuits and program the Arduino to make the green light to be on for 15 min, the yellow on for 4 min, the red for 1 min, and then the piezoelectric buzzer would go off for 5 seconds and the red light would start blinking.

Joe did an awesome job, and the timer worked remarkably well. I did what we wanted it to do, and it actually worked to help them keep their presentations under time.

Elephant Rocks

Students explore the massive, spheroidally weathered boulders at Elephant Rocks State Park.
Students explore the massive, spheroidally weathered boulders at Elephant Rocks State Park.

We stopped at the Elephant Rocks State Park our way down to Eminence MO for our middle school immersion trip. The rocks are the remnants of a granitic pluton (a big blob of molten rock) that cooled underground about 1.5 billion years ago. As the strata above the cooled rock were eroded away the pressure release created vertical and horizontal cracks (joints). Water seeped into those joints, weathered the minerals (dissolution and hydrolysis mainly), and eroded the sediments produced, to create the rounded shapes the students had a hard time leaving behind.

This was a great stop, that I think we’ll need to keep on the agenda for the next the next trip. I did consider stopping at the Johnson’s Shut-Ins Park as well, but we were late enough getting to Eminence as it was. Perhaps next time.

Exploring the spaces between the rocks.
Exploring the spaces between the rocks.

Plate Tectonics on the Eminence Immersion

tectonics-IMG_20141007_093449722

The picture of a convergent tectonic boundary pulls together our immersion trip to Eminence, and the geology we’ve been studying this quarter. We saw granite boulders at Elephant Rocks; climbed on a rhyolite outcrop near the Current River; spelunked through limestone/dolomitic caverns; and looked at sandstone and shale outcrops on the road to and from school.

An oceanic-oceanic subduction zone. The subducting plate melts producing volatile magma.
The subducting plate melts producing volatile magma.

CHICKEN MIDDLE’S FIRST EGG!!!

The first egg from our chickens.
The first egg from our chickens.

Last year, our middle schoolers named their business Chicken Middle. I was a bit skeptical, but the name stuck. This year, thanks to a lot of help from the school community (thanks to the R’s for the Ruby Coops), we finally have chickens (thanks to Mrs. C. for fostering chicks for us over the summer).

And today, we had our first egg. The students were a little excited.

It looks a little lonely sitting there by itself in the egg carton (thanks to Mrs. D., Mrs. P., and everyone else who donated egg cartons), but with a little luck it will have lots of company soon.

A student hand-feeds crickets to the chickens.
A student hand-feeds crickets to the chickens.