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

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)	295	287	282	272	283	303	319	354	351	342	321	291
Macquarie Island, Australia (55ºS)	305	309	303	306	311	309	312	350	379	392	343	321
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

Table 1. Ozone amounts (in Dobson Units) over various cities