Advice: Online quizzes

[asterroc]

So this summer I'm prepping to teach my first online course (to be offered either in Fall 2008 or Spring 2009). In my face-to-face courses I give an open-book timed essay quiz every week, partially to make sure the students are staying on track with their readings, and partially to prep them for closed-book exams. In the online version I will be dropping the closed-book exams and putting more weight into the quizzes, so it's important to me that I do them right. The course I am currently working on is basic astronomy, but if it goes well I will likely work on making other courses available in online versions as well.

The part I'm agonizing over is how much time to allow for the online versions of the quizzes. The problem is that some people will know how to touch-type and therefore will finish faster than they would in a face-to-face quiz, while other students will be hunt-and-pecking and will therefore take longer.

So in addition to just wanting general feedback from you, I'd appreciate it if you'd answer a couple questions that I could give on a quiz (each would be a whole quiz itself, the students would have 20 minutes in a face-to-face class) and tell me how long it took you to do from starting reading the question to finishing the answer. Feel free to use any resources you like for these, including your own textbooks, your own notes, or the internet, just answer in your own words. I don't care if you get these right or not, I'm looking more at how long it takes you to think about them, type them up, and then decide you're done.

Thanks!


1) Explain the cause of the seasons.





















2) Is Pluto currently considered a planet by astronomers? Why or why not?





















3) Compare and contrast the Greenhouse Effect and the Ozone Layer.





















4) Why do astronauts in the Space Shuttle experience weightlessness?




















Thanks for taking the time to answer a couple or all of these, and jotting down how long it took you to answer. And for any other feedback you may have.

X-posted

Comments

My 3-minute answers

[gemini6ice.livejournal.com]

1. The earth is tilted (and this tilt stays fixed rather than following the orbit), and, so, at one side of its revolution, an area spends more time facing the sun than not facing the sun, resulting in greater time warming the air, water, and other stuffs. This is summer.

2. No. I believe a consensus for the definition arose with regard to both size and composition of the orbiting body. To consider pluto a planet, too many other objects would be classified as planets as well, and to keep the name of "planet" dignified, pluto lost.

3. The ozone layer is a portion of the stratosphere (or something) that reflects certain harmful radiations (to a degree), rather than trasmitting them through to the surface. The greenhouse effect is where heat rises from the surface but does not escape, because of greenhouse gases; they trap the heat within the earth's sky.

4. They are free-falling, although I don't quite understand what that means.

[framefolly.livejournal.com]

10:33, started reading. Wow. It's been over 10 years, I think...

1) Explain the cause of the seasons.
The earth revolves around the sun; every full revolution is a year. The earth also rotates on its own axis; every full rotation is a day. These two motions do not occur on the same plane (I wish I could draw a picture!) Because of this difference, for half the year the Northern hemisphere has longer days (more time exposed to the sun) and the other half the year the Southern hemisphere has longer days. Those are the respective summer seasons for the hemispheres. The other seasons also correspond to the relative lengths of daylight for the hemispheres.

10:42

2) Is Pluto currently considered a planet by astronomers? Why or why not?
No, I think, because I heard about it in the news. Okay. More serious answer requires some wiki-ing...
In 2006, the International Astronomical Union (IAU) updated its definition of planets. Pluto fits the first two criteria -- it revolves around the sun and is a sphere by its own gravitational force, but it fails to meet the third and final criterion, which is to clear the neighborhood around its orbit. Recent discoveries have shown that Pluto is one of many similar objects in a region called the Kuiper Belt. In order to account for Pluto and the other objects like it in the region such as Eris and Ceres, the IAU created a new classification called the "dwarf planet." Thus astronomers do not currently consider Pluto to be a planet.

10:53. I got a bit carried away with the web search fun, learned some stuff I didn't know. If this had been a timed test I could have done it faster.

3) Compare and contrast the Greenhouse Effect and the Ozone Layer.
Okay, zandperl, I'm going to try to wing this one even though it's been...???
The greenhouse effect is like what happens in a greenhouse, except on planet-scale. Light energy enters a transparent or translucent medium that encloses a space, like glass (in a greenhouse) or the atmosphere (of the earth). As it bounces off stuff, some of the light energy re-exits the medium, but some of it is converted into heat energy, and is trapped by the medium. That's why I always open my car windows a crack when I park it out in the AZ sun, because if I think the ambient outside temperature of 110+ is bad, I don't want to make my car into a greenhouse to compound the effect. Okay. It's late and I'm punchy. Scratch that. The ozone layer is a part of the earth's atmosphere, and therefore a part of the medium that makes the greenhouse effect possible. I don't know how else to compare or contrast (name the similarities and differences) between the terms, because they're not really like apples and oranges to me, but more like apples and apple juice...If I had to describe the ozone layer better than this to answer the question I'd have to look stuff up, which I'm too lazy to do right now.

11:01

4) Why do astronauts in the Space Shuttle experience weightlessness?
As the shuttle gets farther from earth (and not yet close to any other big object), earth's gravity exerts a lot less pull on it and everything within it. Weight is what we feel when we're moving our masses within and against the force of the earth's gravity. Astronauts in the space shuttle experience weightlessness because they are contending with a negligible fraction of the force of gravity that we experience on the earth's surface.

11:05

Do I pass, teach? Go easy on me -- I haven't taken your class!

[galbinus-caeli.livejournal.com]

9:39am

1) Explain the cause of the seasons.

Two primary causes.

First the axial tilt of the planet causes increased insolation to one hemisphere at a time. When the one rotational pole is inclined toward the sun, radiation falls more vertically and is more readily absorbed. Also because of the inclination the amount of daytime per rotation is increased, allowing more radiation to be absorbed. This will likely be the primary cause of seasonal variation on a non tidally locked planet, such as the earth.

Second, the elliptical nature of a planet's orbit will cause it to be closer to the sun during certain parts of the year versus others. Proximity will cause warmer and cooler seasons. This effect will be minimal for planets with near circular orbits, such as the earth.

A fair assumption is that a tidally locked planet in a circular orbit will not experience seasons.


2) Is Pluto currently considered a planet by astronomers? Why or why not?

Well, some do and some don't, the main international body does not, which is what I think the question is. The latest definition requires that the body in question must have cleared its orbital region of all smaller bodies. Pluto has not done this, and therefore is not a planet.

3) Compare and contrast the Greenhouse Effect and the Ozone Layer.

These are two independent aspects of the Earth's atmosphere.

The Greenhouse Effect is a collection of actions that lead to a higher surface temperature than can be accounted for by insolation alone. One primary factor is an increased insulation factor from certain gases, such as CO₂ and Methane.

The Ozone layer is the effect of high level ozone on surface level UV light. O₃ absorbs UV light. Not sure what more can be said about this.

4) Why do astronauts in the Space Shuttle experience weightlessness?

The more proper term for this is freefall. (or microgravity). Because the space shuttle is in orbit around the earth the acceleration of gravity is balanced by the acceleration of centrifugal psuedoforce. The classic analogy is that the astronauts are falling, but they are moving across the surface of the earth so quickly that they miss the horizon.

Endtime: 10:02

[galbinus-caeli.livejournal.com]

One comment: You did not give any indication of how long an answer you were looking for.

[galbinus-caeli.livejournal.com]

Oh, so far as the time. I did pause twice to help fierce_rabbit with some computer thing and once to run down for coffee.

[jrtom.livejournal.com]

So... 12:48:

(1) The seasons are caused by Earth's axial tilt: between the spring and fall equinoxes, the northern hemisphere is tilted towards the sun, causing the amount of light falling on the northern hemisphere to be greater than that falling on the southern hemisphere. The reverse is true during the other 6 months of the year.
(12:53)

(2) Pluto is not currently considered a planet by astronomers; this is a recent change. In 2006 'planet' was first formally defined by the IAU to be something that orbited the sun, was essentially spherical, and cleared its orbit of debris; Pluto does not satisfy the third criterion and is therefore called a 'dwarf planet'. As of 11 June 2008, Pluto (and other dwarf planets outside Neptune's orbit) are now a class of their own, called 'plutoids'.
reference: http://en.wikipedia.org/wiki/2006_definition_of_planet
(12:58)

(3) [Skipped. This question doesn't make a lot of sense to me. "Discuss the relationship between the phenomenon known as "the greenhouse effect" and the ozone layer" would make more sense, but "compare and contrast" implies that they're the same kind of thing or phenomenon, and they're not. It's sort of like being asked to compare and contrast "inflation" and "the money supply".]

13:01
(4) The same reason anyone who's falling feels weightless: the force due to gravity is not being opposed by any other force, and there's not enough tidal effects (differential acceleration on different parts of their bodies) for them to be able to perceive such effects. They're falling in an essentially circular trajectory around the planet. (The question of why their trajectory is circular is a separate one; for that one, insert more quarters. :) )
13:06

Side point: I type probably in excess of 70 wpm, so you may want to factor that in.

[zandperl.livejournal.com]

Lots of people have been complaining about that third question. When I teach a class where I have that question, I usually make it clear in the course of the lecture what I mean. I'm planning to give my answers to all four questions on Monday in case people are curious.

[hitchhiker.livejournal.com]

t=16:53
1) Explain the cause of the seasons.

The earth has an axial tilt of 23 degrees. As it orbits, the angle of incidence of sunlight on various parts of it varies accordingly; colder seasons are those in which the sunlight falls at a shallower angle.

t=16:55

2) Is Pluto currently considered a planet by astronomers? Why or why not?

Nope. After the discovery that there are potentially thousands of Kuiper belt objects of greater size and mass, Pluto was demoted to a trans-Neptunian object (and, most recently, reelevated to a 'plutoid', which should at least satisfy the more sentimental among us :))

t=16:56

3) Compare and contrast the Greenhouse Effect and the Ozone Layer.

The atmosphere is more transparent to a portion of the infrared spectrum in direct sunlight than to the lower-energy spectrum reflected back off the earth. Therefore, a certain percentage ends up converted to heat rather than reflected back into space, a phenomenon known as the greenhouse effect. The ozone layer provides the opposite effect - it does not pass a range of sunlight in the ultraviolet spectrum, and therefore blocks it out from the directly incident radiation

t = 17:00

4) Why do astronauts in the Space Shuttle experience weightlessness?

They're in "free fall" - experiencing the same acceleration as everything around (and within) them.

t = 17:01

[internettourist.livejournal.com]

I teach on line classes using Angel. To make sure students are reading as scheduled, I have untimed participation assignments students get full participation credit for if the assignment is at least 70% correct. This keeps the student from feeling too pressured. These assignments are submitted through drop boxes.

My tests have a timed objective question component and a non-timed component. I created the time tests with Respondus.

Each term one student will vigorously tell me that I have not given them enough time to take the test. Perhaps two others will comment about the time. Perhaps accounting students could beel a little more pressured and be a little more testy than students in other discplines. My distance learning economics students never say anything about the time limits I have in their courses.

I didn't take astronomy as a student. I took botany and chemistry. So the only value from my answering astronomy questions would be laughs.

I'll post my budgie update.

[zandperl.livejournal.com]

Do you find it takes your students more or less time to answer questions online than face to face?

Children do not breed budgies in your homes

[internettourist.livejournal.com]

Baby budgie update




I took this picture Thursday.



About 27 days ago, I found an egg in Lucy's box. Every two days after that she'd
lay an egg laying a total of 9 eggs. Eighteen days after the first egg as laid,
the first chick hatched. One chick hatched about every second day. A total of
six chicks hatched. About two days ago, Lucy started spending a lot of time out
of the box. It seemed like she'd only go in to feed them. About the same time
daddy Mikey started taking on feeding.



The chicks were sitting on the unhatched eggs looking like they were uncubating
them. But then the chicks would make their own pile excluding the 3 unhatched
eggs. An egg was suppose to hatch yesterday, but it didn't. So I thought I might
incubate them myselves by wrapping them in a cloth and putting them in a low set
heating pad. The pad seemed nice. But at night I checked on the eggs, they
seemed too hot to me, probably because I had the heating pad on both sides of
the egg generating too much warmth. I probably should have put the pad just on
one side with the cloth on top keeping the warmth in. I'll leave the eggs there
with one side touching he pad.



Well I have 6 chicks. I thought those white coaster thingies were egg shell
debris created by Lucy. It was Thursday that I discovered they were baby poop.
So I put them in a different box with two fresh cloths. They are pooping like
little fiends now. And it's starting to turn normal color (green).



When I transfered the babies to the new box, I transfered the two littliest
first because that was scariest moving them. I'll give them clean clothes again
tomorrow. Hopefully two littlest buggers will be a little bigger then.



Three of them have their eyes open. They are starting to get cute. Their bodies
are starting to turn blueish. But mom is yellow green and dad is white with a
touch of blue gray on the underside, so I know that those babies probably won't
be blue.



Lucy this week has started eating foods herself with Mikey feeding her here and
there. The three weeks before she was exclusively feed by Mikey.



Lucy these recent days has started chasing my other female Ella around the cage.
Ella use to be her BFF.



Lucy has plucked a bald spot on her chest. Mikey and she are lean and messy
looking with dark green stains around their beaks from all that feeding. I have
been putting out more stuff to eat due to their feeding burdens.



Well that's my baby update. I won't be having more babies. In a week or two I'll
post another picture and update.