Particulates in the Air
Exercise Inventory
Materials
(3) 5 cm Petri dishes
5 g Petroleum jelly
Hand lens
(1) Pair of gloves
Permanent marker
Note: You must provide the materials listed in *red.
EXERCISE 1: PARTICULATES IN THE AIR
Our atmosphere is full of all sorts of particulates that can contaminate our air, both indoors and outdoors.
The types of suspended particles that we encounter vary depending on our location.
In this laboratory exercise, you will collect and analyze particulates from the air in several different locations over the course of three days.
PROCEDURE
1. Put on a pair of gloves.
2. Use a permanent marker to label the lids of three 5 cm petri dishes as follows: “Control,” “Collector 1,” “Collector 2.”
3. Flip the petri dishes over (with the lids still on) so the bottoms are facing up.
4. On one of the dishes, use a permanent marker to draw a vertical line and then a horizontal line that intersect at the middle of the dish, creating four equal quadrants. Label the quadrants 1, 2, 3, and 4 (Figure 6).
Figure 6. Example of how your petri dish should be labeled.
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5. Repeat Step 4 for the other two dishes.
6. Flip the petri dishes back over so that the lids are facing up again.
7. Take off the lid of the “Control” petri dish and inspect the inside to make sure there are no particles (dust, fibers, etc.) inside the petri dish. If there are any, wipe them out using your finger (with a glove on).
8. With a gloved hand, smear a very thin layer of petroleum jelly along the bottom of the inside of the petri dish. The entire bottom of the dish should be covered in a smooth, thin layer of petroleum jelly.
9. Immediately replace the lid back on top of the “Control” petri dish and set the petri dish aside.
10. Repeat Steps 7–9 for the “Collector 1” and “Collector 2” petri dishes.
11. Choose two different locations to store your two collectors. Ideally, one location should be inside and one location should be outside. The “Control” collector should remain covered in your normal laboratory area.
12. Record the locations of where you are storing your collectors in the titles of Table 3, Table 4, and Table 5 on the Exercise 1
Data Sheet.
: You will need to store the petri dishes for 3 days, so choose locations where the collectors will not be disturbed.
13. Develop a hypothesis of what you think you will observe on the collectors after three days and record it in the space provided at the top of the Exercise 1 Data Sheet.
14. Take your collectors to their locations, remove their lids, and store the lid underneath the bottom of the petri dish so that the petroleum jelly is exposed to the air.
15. After three days, bring the collectors back to your laboratory area.
16. Use a hand lens to observe the particles you have collected inside your petridishes.
Note: Examine your petri dishes in a well-lit area and use several different backgrounds underneath the dishes to make the particulates easier to see. For example, a dark-colored desk, a white piece of computer paper, etc.
17. Count the number of particulates in the quadrants of each collector dish and do your best to identify (or at least describe) the different types of particulates that are present in each quadrant. Record this data in the tables on the Data Sheet.
18. Calculate the total particulates in each collector by adding together the number of particulates in each quadrant. Record these values in the tables on the Data Sheet.
19. When you are finished counting and describing the particulates, dispose of the petri dishes in the garbage.
20. Answer the Post-Lab questions.
©eScience Labs, 2018
Data SheetExercise 1 Data Sheet
Hypothesis:
Table 3. Collector #1:______________________________
Quadrant # Number of
Particulates Type/Description of Particulates
1
2
3
4
Total:
Table 4. Collector #2:______________________________
Quadrant # Number of
Particulates Type/Description of Particulates
1
2
3
4
Total:
Table 5. Control:________________________________
Quadrant # Number of
Particulates Type/Description of Particulates
1
2
3
4
Total:
©eScience Labs, 2018
