What Is Pollution Anyway?

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Objective

SWBAT identify several ways that our environment is polluted by everyday use

Big Idea

Can engineers help to solve problems of pollution?

Teacher Background

In order to engage students in meaningful discourse about science, and in particular about pollution in their own community students need some background about what pollution is. They can not discuss something that they do not really understand. 

This lesson is intended to give students some background knowledge and to check on their prior knowledge about what pollution is and how it effects each of us. This lesson is the beginning of several lessons centered around pollution in the community. To begin I need to informally assess what children already understand about pollution. I can connect to their prior knowledge and scaffold new learning if I know what students  already understand. 

I will focus this lesson around gathering prior knowledge and providing additional background as needed to understand how pollution effects our community.

Accessing Prior Knowledge

15 minutes

I begin today without an "I Can" statement that I usually use to introduce what we will be doing today. I want to access prior knowledge so I am going to wait until later to highlight the I Can. I will use pictures to encourage students to discuss the topic of pollution.

I post a picture of a beach covered with litter on the Smart Board. I ask, "can anyone tell me what they see in this picture?" I let students share what they see without commenting on their responses except to repeat them louder if the student said it so quietly that not everyone may have heard. 

Next I post a picture of a city with smoke coming from the smoke stacks. I ask, "can anyone tell me what they see in this picture?"A Student Discusses One Of The Pictures For both pictures I do not yet pick up on any comments about the trash or smoke.

Finally I post a picture of a stream with litter and water that does not look clean. Again I ask students to explain the picture.

After everyone has shared, I put the three pictures up side by side and ask, "Do these pictures have anything in common?" Students might notice the water in 2 of them, sky, etc. but I wait to see if they notice that all 3 show some form of pollution. If someone brings up the words litter, pollution, smoke, I ask, "does anyone know what the word pollution means?" I take several suggestions. I repeat this with the word litter. 

I note on sticky notes how many people brought up ideas of pollution, or the words, or raised their hands when I asked what it meant. If most hands are raised, I feel that students have some background with what pollution is. If none are raised, I want to start with explaining pollution. My goal is to have a sense of what students already know before continuing with the lesson. 

What Causes Pollution

15 minutes

This section will give me another opportunity to assess prior understanding of pollution. 

I say, "I have a question for you but I only want you to think about the answer right now. When I ask the question, I am going to give you a piece of paper and I want you to write and draw your answer. I don't want you to share your ideas yet, but don't worry, you will have a chance in a little while."

I hand out paper and then say, "Ok, here is the question I want you to draw and write an answer for. Where does pollution come from? You may draw one picture, or divide your paper and draw several pictures to answer my question. Does everyone understand what to do?" I ask one student to repeat the directions. I give the quiet signal and ask students to begin working. I circulate around looking at drawings and talking to students about their work.

The pictures give me the opportunity to assess their understanding of where pollution comes from and what it really is.

A Well Done Student Paper

A Student Paper that Shows Only Minimal Understanding of the Assignment

A Student Expresses Her Idea Using Drawings

Sharing Our Ideas

20 minutes

I post an I Can statement before we share. I want students to engage in meaningful discussions about science and here I am encouraging them to discuss their understanding of where pollution comes from. Pollution is an important topic in today's world. Students should be able to talk about why pollution is a problem in our community, as well as in the larger world view. In a second grade appropriate manner, I want students to discuss how pollution is a problem so that later in this unit they can think of how to help prevent the problem.

 Now that students have seen the pictures I posted, and had a chance to come up with their own answers to the question, "where does pollution come from," I feel that they have something to discuss. My I Can statement reads, "I can talk about where pollution comes from."

I say, "Let's read the I Can statement together and then we will know what we will be doing next. "I can talk about where pollution comes from. Ok, so now I want each of you to share your ideas about where pollution comes from. Is is OK to ask questions if you are not sure what someone is explaining?" (yes) "What might you do if you don't agree with someone?" (I let students think of possible ways to deal with a disagreement.) I am going to have you meet in science teams (groups of 3 students). You will each present your picture, tell where you think pollution comes from and ask your group for questions or comments. You will need to take turns sharing. Are there any questions before you move to your teams?"

Students move to areas of the room to discuss their pictures. I circulate around to encourage students to listen to each other and to ask questions. I listen to see what students are thinking about where pollution comes from. Do they think it is just litter dropped on the street? Do they realize that pollution can also come from things such as smoke or cars? Do they think of pollution as things that might get spilled into the water? These are the types of things I am listening for as I observe each group.  I am hoping that by giving students a framework to work in, they will be able to sustain a conversation for about 5 minutes with their groups.

Debriefing

10 minutes

Debriefing is an important part of the scientific process. I was able to assess prior knowledge in this lesson and then to encourage students to engage in a meaningful discussion about pollution, but I do not want to just stop there. I need to give students a chance to debrief and sum up all that we talked about today. 

I ring the bell for attention and ask students to return to their own seats with their pictures. I ask, "does anyone want to share out something that their group talked about today?" I let individuals share the ideas, thoughts and questions from their discussions. I may also share something I heard as I was circulating around the room. 

I close with the I Can statement. I ask students to show with a thumbs up if they think they were able to talk about pollution with their friends today.

I collect the pictures to use as part of the informal assessment of prior knowledge.