Explain that this is how tar affects the cilia. Tar and nicotine slow the cilia and prevent them from sweeping out dust, dirt and germs. Nicotine also paralyzes the cilia for several hours. This is one reason why smokers have more sore throats, coughs and colds than nonsmokers. Review additional chemicals in tobacco.
Groups research tobacco ingredients.
Divide class into small groups and give each group a copy of the student page. Assign each group a different ingredient of tobacco to research and report on to the class. Review, summarize and discuss. As groups report, discuss how students can tell a source is trustworthy. See Identifying Valid Sources for Information.