1. Preview and choose one (or show both) of the Waste Water Treatment Videos to show your class.
2. Before showing the video(s), ask students what sewage or "waste water" is; have them be specific.  Ask students where they think sewage goes after it leaves their homes and schools.
3. Pair up students and have them think about what would need to be done to that sewage to make it clean enough to put back into local water bodies- what kind of specific processes  might need to be done to clean dirty water? Have partners share out with the class.
4. Show students the video and then have a class discussion about what they new before and what they learned after having watched the video. Tell students that during the next series of lessons they will be exploring hands-on how to clean water.

DO NOT tell the students "THE ANSWER".  Tell students that with the elicitation questions we are looking for all the different ways, models and theories that might explain the situation. Let students know that during the following lessons we will sort through all these ideas, but we need to have lots of ideas so that we can eliminate some.

Typical student responses you hope to hear during this engagement lesson:

• Many students think that sewage is just "poop"!  Help clarify that all water that goes down the drain is sewage and has to be treated- this is why its so important not to flush trash and medicines down the toilet or allow toxic substances to go down storm drains (storm water is generally NOT treated first).
• Many students think that the water they drink is from one clean source somewhere and that sewage just goes away. Remind students of their learning about the water cycle and have them think about how the urbanization of Earth has changed some of those natural processes.  

• Waste Water Treatment Video 1
• Waste Water Treatment Video 2