Learning activity 2: Identifying ozone variations across different cities
Purpose: To allow student to identify what cities are affected by the ozone hole, and confront
misconception that the ozone hole is over Australia. This activity goes along with Lesson 2, and
assumes some background knowledge of the ozone hole.
Materials Needed:
Provided monthly ozone data for various locations.
Paper and ruler (or graph paper)
Procedure:
Assemble students into groups of 2-4. Provide students with monthly ozone data
(provided) over a number of locations (Australia, Antarctica, Europe or America). Ask students
to plot out ozone levels at different locations for the 12 months of the year, and answer provided
questions.
You may wish to answer questions in group discussion. You may start by asking where lowest
ozone levels were, and where highest ozone levels are. Discuss what the definition of the ozone
hole is, and compare data to see what locations have low ozone values. Discuss the timing of the
ozone hole, and ask students why low values occurred in the months they do.
Assessment suggestions:
Students could be marked by their group answers which they turn in at then end of the class.
Teacher Notes:
From the data, it is clear that the ozone hole is present from Aug – Oct over Antarctica, but not
over Australia according to the definition of an ozone hole, which says ozone levels below 220
Dobson Units (DU). In fact, during the ‘ozone hole season’, Australian ozone levels are at their
highest level. This is the bottom line for this activity.
The reason ozone fluctuates from season to season is due primarily to prevailing winds in the
atmosphere. During winter and spring, winds transport more ozone into the higher latitudes from
the ozone production area of the tropics.
A sample graph is provided below
Total ozone over various cities
400
350
Total Ozone (DU)
300
Melbourne (37S)
Macquarie Island (55S)
Darwin (12S)
250
London (~55N)
San Francisco (35N)
Halley Bay, Antarctica (80S)
Ozone Hole Limit
200
150
100
Jan
Feb
Mar
Apr
May
Jun
Jul
Month
Aug
Sep
Oct
Nov
Dec
Learning Activity 2: Identifying ozone variations across different
cities
In this activity, you will study ozone variations over different cities to examine how
ozone normally changes month to month. In the second part of your analysis, you will determine
if and when the ozone hole occurs over these cities.
Your first step is to plot on a graph ozone levels for four cities on a piece of paper or graph
paper. The data provided below is average total ozone in Dobson Units (DU) for each month of
the year.
Once you have plotted out the data, answer the following questions.
1. During what season (i.e. Spring, Autumn, Winter or Summer) do the highest values of
ozone occur over Melbourne?
2. When do the lowest ozone values occur over Antarctica? Why?
3. For which location does the ozone hole exist? (ozone hole is 220 DU or less)
4. How long does the ozone hole last for?
5. Is the ozone hole over Australia?
6. When are ozone values normally the highest over Melbourne?
7. When are ozone values normally the highest over the Southern Hemisphere?
8. When are ozone values normally the highest over the Northern Hemisphere?
Finally, write a paragraph supporting or denying the following statement:
“The ozone hole comes over Australia for at least one month every year”
Month
City and latitude
Jan
Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Melbourne, Australia (37ºS)
Macquarie Island, Australia
(55ºS)
295 287 282 272 283 303 319 354 351 342 321 291
Darwin, Australia (12ºS)
280 273 270 271 275 279 282 290 301 304 290 279
London, England (51ºN)
339 331 358 374 375 360 351 337 303 291 278 315
Brisbane, Australia (27ºS)
277 273 271 271 271 275 282 290 300 303 295 284
Hobart, Australia(43ºS)
313 301 293 294 308 321 334 350 364 364 343 322
San Francisco, USA (37ºN)
309 324 335 340 337 323 310 303 293 283 281 292
Halley Bay, Antarctica (76ºS)
286 261 251 245 250 239 220 179 151 137 267 299
305 309 303 306 311 309 312 350 379 392 343 321
Table 1. Ozone amounts (in Dobson Units) over various cities