Formative and Authentic Assessment

Instead giving counterproductive, high-stakes exams, David Jaffee promotes formative and authentic assessment methods.

Formative assessment happens during learning, usually in the classroom. Students do something, like an assignment, and get immediate feedback on what they did. A teacher walking around from student to student or group to group, following what the students are doing and helping students identify which concepts they’re not getting, is a typical example of formative assessment.

Authentic assessments are assignments that are or mimic real-world problems, and require students to apply the stuff they should have learned to solving them. I’m using projects like the draining of a bottle and carpet friction experiments to assess if my students truly understand why they do algebra and calculus, and are able to apply the techniques they’ve learned.

Caveat: It is important to note, however, that being able to solve real-world problems requires some abstract thinking skills that adolescents are still developing. Yet, even though a lot of the basic learning in middle and high school consists of ingesting the language of the different fields of study — they type of thing that is easy to test — a more useful assessment is likely to be one that requires students to use their new vocabulary in written assignments, such as project reports and essays.

Don’t Study for Your Exams

… cramming—short-term memorizing—does not contribute to retention or transfer [my emphasis]. It may, however, yield positive short-term results as measured by exam scores.

— Jaffee, 2012: Stop Telling Students to Study for Exams in The Chronicle of Higher Education.

It’s getting close to the end of the academic year, and exams are coming up. David Jaffee advocates that we stop telling students to study for their exams; they should, instead, study for learning and understanding.

Jaffee especially piles on on Final Exams:

This dysfunctional system reaches its zenith with the cumulative “final” exam. We even go so far as to commemorate this sacred academic ritual by setting aside a specially designated “exam week” at the end of each term. This collective exercise in sadism encourages students to cram everything that they think they need to “know” (temporarily for the exam) into their brains, deprive themselves of sleep and leisure activities, complete (or more likely finally start) term papers, and memorize mounds of information. While this traditional exercise might prepare students for the inevitable bouts of unpleasantness they will face as working adults, its value as a learning process is dubious.

— Jaffee (2012).

The alternative to exams, Jaffee suggests, is formative and authentic assessment.

Crayfish in the Creek

crayfish-1184 — Crayfish camouflaged against the rocks in the creek.

One of my favorite things about the Fulton School campus is the little creek that runs along the boundary. It’s small, dynamic, and teeming with life.

The crayfish are out in force at the moment. Some of the high-schoolers collected one last fall and it survived the winter in our fish tank (also populated with fish from the creek).

They are quite fascinating to observe; wandering around the sandy bed as if they own the place; aggressive with their pincers occasionally; but then darting backward amazingly fast if they feel threatened.

The one in our tank has just molted a second time, so now we have two almost perfect exoskeletons sitting around the science lab.

crayfish-1233 — Crayfish exoskeleton. From pincers to tail the skeleton is approximately 10cm long.

Why are Earth’s Sunsets Red While Mars’ are Blue?

marspath_ss24_1 — The area around the Sun is blue on Mars because the gasses in the thin atmosphere don't scatter much, but the Martian dust does (it scatters the red). Image via NASA.

The dust in Mars’ atmosphere scatters red, while the major gasses in Earth’s atmosphere (Nitrogen and Oxygen) scatter blue light. Longer wavelengths of light, like red, will bounce off (scatter) larger particles like dust, while shorter wavelengths, like blue light, will bounce of smaller particles, like the molecules of gas in the atmosphere. The phenomena is called Rayleigh scattering, and is different from the mechanism where different molecules absorb different wavelengths of light.

Ezra Block and Robert Krulwich go into details on NPR.

ny-2-39-f60 — Blue sky in the upper right, but the dust scatters the red light.

Flatulence … in Space

For every action there is an equal and opposite reaction.

— Newton’s Third Law of Motion

I introduced my Middle Schoolers to the principles of Newton’s Laws of Motion last week.

The discussion started off with projectiles. If you’re floating in space — zero gravity — and throw something, like a basketball, away from you, you’ll be pushed off in the opposite direction. In fact, if you throw something that has the exact same mass as you do away from yourself, you’ll move off in the opposite direction with the exact same speed as the thing you threw.

Then I brought up rockets, and how they’re expelling gas to move them forward. I think it was the phrase, “expelling gas” that did it. The next question, which the student brought up somewhat circumspectly, sidling around the issue and the language, was (more or less), “So if you expel gas in space will you move off in the other direction?”

The simple answer, appropriate to that stage of the discussion, was, of course, “Yes.”

Which lead to to, “What about spitting?”

“Yes.”

“What about, you know, peeing?”

“Yes, except …”

At that point I thought it would be wise to rein it in a little, and make a further point about the whole action-reaction thing.

“You see, if you expel anything, wouldn’t it just be stuck in your spacesuit with you? Then you’re not really expelling it, it’s still attached to you, so you wouldn’t really move. What would be more useful would be to collect it in something like a spray can or a squeeze bottle. Then you can just squirt it out opposite the direction you want to go in to control your movement.”

This produced a moment of thoughtful silence as they figured out the logistics.

Notes

I thought this was a useful conversation to have. The students were interested and animated. And I believe it’ll be memorable too.

P.S.: I’d wanted to talk about ion drives, which operate on the same reaction principle, but are much cooler (after all they’re used in Star Trek). Instead of burning fuel to create the propulsive force ion drives generate an electric field that ejects charged particles; we’d been talking about ions and charged particles earlier in the day. However, I decided on the day that it would just complicate what was a new issue. I’ll probably bring it up this week though as we recurse through Newton’s Laws.

A Better Commencement Address

2. Some of your worst days lie ahead. Graduation is a happy day. But my job is to tell you that if you are going to do anything worthwhile, you will face periods of grinding self-doubt and failure.

— Wheelan, 2012: 10 Things Your Commencement Speaker Won’t Tell You in The Wall Street Journal

Charles Wheelan provides an excellent perspective on what should be important in a commencement address.

I particularly like this warning about the danger of working only for rewards:

8. Don’t model your life after a circus animal. Performing animals do tricks because their trainers throw them peanuts or small fish for doing so. You should aspire to do better.

— Wheelan, 2012: 10 Things Your Commencement Speaker Won’t Tell You in The Wall Street Journal

And this point on conservation and the real meaning of being conservative:

3. Don’t make the world worse. I know that I’m supposed to tell you to aspire to great things. But I’m going to lower the bar here: Just don’t use your prodigious talents to mess things up. Too many smart people are doing that already.

— Wheelan, 2012: 10 Things Your Commencement Speaker Won’t Tell You in The Wall Street Journal

↬ The Dish

Searching for the Higgs Boson: How Science Really Works

PhD Comics does a wonderful job of explaining of sub-atomic particles: what we know, what we don’t know. What’s particularly great about this video is that it goes into how physicists are using the Large Hadron Collider to try to discover new particles: by making graphs of millions of collisions of particles and looking for the tiniest of differences between different predictions of what might be there.

I also like how clear they make the fact that science is a processes of discovery, and what fascinates scientists is the unknown. Students do experiments all the time and if they don’t find what they expect — if it “doesn’t work” — they’re usually very disappointed. I try my best to let them know that this is really what science is about. When your experiment does not do what you want, and you’re confident you designed it right, then the real excitement, the new discoveries, begin.

Harvesting and Processing Chickens

We successfully harvested and processed three chickens during last week’s interim. It was my first time going through the entire process, but fortunately we had a very experienced guide in Dr. Samsone who also happens to be a vet.

The interim focused on where food comes from (students also saw the documentary “King Corn”), and the cleaning of the chickens was tied into our Biology students’ study of anatomy (I’d done fish and squid before). Unfortunately, I was unable to find someone who knew how to read the entrails so we could tie the process into history and language arts as well.

chicken-1085 — Student holds a kidney. A heart is in the background.

When we were done with the processing and analysis, Mr. Elder cooked the chickens on our brand new grill (which worked quite well he says). The chickens were free-range (donated by Ms. Eisenberger), but a little on the old side, at about 7 months old; the chickens you buy at the grocery are somewhere around 2 months old.

Dr. Samsone recommended that next time we raise the chickens ourselves from chicks, which I’d love to try, but I suspect would run into some serious resistance from the students. We’d only had the chickens we harvested for five minutes before they’d all been given names. Raising chickens from chicks would bring a whole new level of anthropomorphizing.

chicken-grill-4826 — Chicken on the grill. The culmination of the interim.

References

Being new to the chickens, I spent a bit of time researching how it is done.

Ken Bolte, from the Franklin County Extension of the University of Missouri, recommended the University of Minnesota’s Extension site on Home Processing of Poultry (the page on evisceration provided an excellent guide), as well as Oklahoma State’s much briefer guide (pdf).

Dr. Samsone recommended the series of videos from the Featherman Equipment Company. Videos are particularly useful for novices like myself.

Herrick Kimball’s excellent How to Butcher a Chicken is also a great reference.