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

[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