Objectives
Students will:

manipulate numbers and calculate using the power of 10 explain the impact of shapes of particles explain the impact of the composition of particles explain health concerns related to particulate matter

Materials

rolls of white register/receipt tape blank paper colored pencils metric rulers and yardsticks calculator (optional) Computers with internet access Student Worksheet (pdf)

Assessment
As a class or individually, answer the following question:

1. What do you think is more dangerous, fine particles (2.5 micrometers) or coarse particles (10 micrometers)? Explain.
   

Extension:
To demonstrate particle size in a simple, macroscopic way, create a mixture of particulates varying in size. For example, mix some small gravel, sand, etc. Add a little water to the mixture. First pass the mixture through a colander or large strainer, collecting the sieved material in a bowl. Show the students how most of the large particles (gravel) is captured, while the particles with smaller diameters pass through the openings. Pass the mixture through progressively smaller sieves, and then coffee filter paper demonstrate why the size of the particle influences where and how far a particle can travel. Students may be surprised as to how many particles travel through the filtering process.

Discuss with students how parts of the human body act as a series of sieves to stop particulates and other foreign matter from entering. The hairs inside the nostrils help to trap particles, etc, however very small particles can still make their way through and get lodged in lung tissue, which can cause or trigger health problems.

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