"Tonight's forecast: DARK! Continued mostly dark tonight turning to widely scattered LIGHT in the morning, man!"
--George Carlin, Last Words, Simon & Schuster, New York (2009).
Equipment
Cuesta ThinkPad laptops (wireless networking, internet browser)
(appropriate, responsible in-class use of personal laptops allowed)
Current Events Quiz
(First 10 minutes of laboratory.)
Briefing
Inquiring About Earth's Weather (*.blog)
Big Idea
Earth's weather is a complex phenomenon with a large impact on astronomy observations. A large amount of data has been recorded of past weather conditions that can be analyzed to identify statistical trends; forecasts of future weather conditions is available to best schedule observing time.
Goal
Students will conduct a series of inquiries by analyzing historical, current, and predicted weather conditions.
Computer Setup
Access the nearest Weather Underground site for your campus by clicking on the appropriate link below:
*Main campus, San Luis Obispo, CA (*.html)
*North County campus, Paso Robles, CA (*.html)
Tasks
(Record your lab partners' names on your worksheet.)
1. Exploration
- Complete the first two rows of the table below for today (recorded and/or forecasted data), yesterday, and this date one year ago.
| Max.
Temp.
(°F): | Min.
Temp.
(°F): | (Peak)
Precip.
(inches): |
| Today | | | |
| Yesterday | | | |
| One year ago | | | | | | |
- For yesterday, make a few rough sketches of how the temperature,
cloud cover, and wind speed have changed throughout that day (you don't have to be completely accurate, just such that your rough graphs are recognizably equivalent to the online graphs). Be sure to clearly label the horizontal and vertical axes of your graphs of:
Cloud Cover vs. time,- Temperature vs. time,
- Wind Speed vs. time.
- Consider the research question, "How are the weather conditions here today (up to now) different than yesterday?" In order to pursue evidence for this question, first create a short, written description of today's weather by describing the important characteristics and measurements. Then, create a second, short, written description of yesterday's in much the same way. Finally, complete your full response by composing a description of how the two days are different. Be sure to include temperature, precipitation,
cloud cover, and wind speed.
2. Does Evidence Match a Given Conclusion?
Consider the research question of "How much does the weather change year to year?" If a student proposed a generalization that "the temperature here today is about the same as it was at this same location on this same date, but back in the year you were born," would you agree or disagree with the generalization based on patterns you can find in the evidence you collected in the previous section or using new evidence? Explain your reasoning and provide specific evidence either from the above questions or from any new evidence you yourself generate using this website.
3. What Conclusions Can You Draw From This Evidence?
Wind is caused when air rapidly moves from one place to another. Typically best telescope viewing is done when the air is calm, to minimize "twinkling" from atmospheric turbulence. What conclusions and generalizations can you make from the following data collected by a student in terms of "What season of the year (in 2009) was best suited for telescope viewing in San Luis Obispo, CA?" by analyzing which season (winter, spring, summer, or fall) has the greatest or least peak wind speed, and most or least number of weeks with more than 50% cloud cover.
| | Month
(2009): | Peak Wind
Speed (mph): | Weeks w/More than
50% Cloud Cover: |
| | Jan | 5.6 | 1.0 |
| | Feb | 6.7 | 1.5 |
| | Mar | 8.9 | 0.5 |
| | Apr | 11.0 | 1.0 |
| | May | 12.3 | 3.0 |
| | Jun | 7.8 | 1.0 |
| | Jul | 7.6 | 1.0 |
| | Aug | 9.2 | 1.0 |
| | Sep | 6.9 | 0.0 |
| | Oct | 7.4 | 1.0 |
| | Nov | 5.4 | 1.0 |
| | Dec | 5.4 | 1.0 |
Explain your reasoning and provide specific evidence, with sketches if necessary, to support your reasoning(*).
4. What Evidence Do You Need to Pursue?
Condensation is a common problem for telescopes: You're out with your telescope on a pleasant summer evening, up late... You notice something strange. The dim stars begin to fade. The images of the bright stars suddenly have ghostly white haloes. And finally, you can barely see anything at all.
The stars are gone.
You look at the sky. Have clouds rolled in? No. All clear.
Then, you take a peak [sic] at the lens of your telescope. A thick layer of water--dew--has condensed on your lens.
You don't dare wipe the dew off the lens for fear of damaging the soft anti-reflection coatings. And with no other way to remove the coating of water, your idyllic observing session has come to an early end. All you can do is pack up and go home, with your ambitious observing plan left undone.
What happened?
Condensation. The temperature of your telescope's lens fell below the so-called "dew point." And just as when you take a bottle of cold beer out the fridge, a swarm of water molecules from the surrounding air condensed onto the glass like locusts on a field of wheat.
--One Minute Astronomer Blog, "Don't 'Dew' This With Your Telescope...,"
April 29, 2010 (*.html) The dew point is the temperature at which condensation starts to accumulate due to humidity. If the temperature of your telescope (approximately the same as the ambient air temperature) falls below the dew point, condensation will begin; if the temperature is above the dew point, no condensation forms. One method to actively prevent condensation is to use built-in electric warmers to keep the telescope temperature above the dew point. A dew warmer may affect observations by creating warm air updrafts, so a dew warmer should only be turned on when necessary.
Describe precisely what evidence you would need to collect and how to collect it in order to answer the research question of, "If a robotic telescope were to make continuous observations tonight, from one hour after sunset to one hour before sunrise tomorrow, what time(s) should the dew warmer be programmed to run?" (Running the dew warmer continuously all night may needlessly create local thermal drafts that would affect viewing.) You do not need to actually complete the steps in the procedure you are writing. (For the purposes of this activity, assume that the sky will be clear tonight for observations.)
Create a detailed, step-by-step description of evidence that needs to be collected and a complete explanation of how this could be done--not just "look up the 10-day dew point forecast," but exactly what would someone need to do, step-by-step, to accomplish this. You might include a table and sketches--the goal is to be precise and detailed enough that someone else could follow your procedure.
5. Formulate a Question, Pursue Evidence, and Justify Your Conclusion
Design an answerable research question (*.html), propose a plan to pursue evidence, collect data, and create an evidence-based conclusion about an aspect that you have not completed before. (Have your instructor approve your whiteboard research question before proceeding further.)
Research report summary on whiteboards(*), to be worked on and presented as a group, should include:- Specific research question.
- Step-by-step procedure to collect evidence.
- Data table and/or results.
- Evidence-based conclusion statement.
Preparation/Reflection Points
1.0 = Pre-lab reading assignment
1.0 = Current events quiz
1.0 = Post-lab reflection assignment
Group Work Points(*)
Documentation (Tasks 1-4, graded from randomly selected group member)
2.0 = exploration complete and reasoning correct
1.5 = minor problem with exploration or reasoning
1.0 = minor problems with both exploration and reasoning
0.5 = problematic exploration and reasoning
Poster/presentation (task 5)
2.0 = research report complete and competent presentation
1.5 = minor problem with research report or presentation
1.0 = minor problems with both research report and presentation
0.5 = problematic research report and presentation
(Backwards Folded Scaffolding laboratory adapted from: Tim Slater, Stephanie Slater, Daniel J. Lyons, Engaging in Astronomical Inquiry, W.H. Freeman & Company, New York (2010), pp. 33-37.)
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