I call students to the gathering area and hand each of them a soda can from the school’s recycling bin (make sure to wash them well beforehand!)
I ask them how the soda can that they are holding helps them understand the rock cycle. Quite often, students look back at me blankly. I start to probe them to try to think about how that can was made.
How was this can made?
Was it mined in this form?
Was it grown?
Was it sown together to form the cylinder?
Usually someone starts to read the can and notices it has a recycled sign on it.
“Aha!” I say. I ask if anyone knows how aluminum is recycled? Usually no one can answer this question with great detail.
I tell students that the recycling process is a metaphor for the rock cycle. I want them to think of this as they are researching the recycling process. Hopefully, by putting this idea into their heads I encourage them to make the connections to the rock cycle as they are researching.
When I make this connection to the rock cycle, it is interesting to hear students' conversations as they are researching. They make many more connections than if I don't make the direct connection. I don't feed them the actual parts of the cycle that are connections, they are able to make those connections with the information they have learned so far, and other prior learning.
I place students in groups of three and tell them that they will research the process of recycling aluminum cans. I have a class website that I have preloaded sites for them to visit to complete this research. One of sites is a movie about how aluminum cans are made. This offers students who have difficulty reading English a chance to listen to the information and/or watch the process.
The video site is: https://www.youtube.com/watch?v=7dK1VVtja5c
Other websites about recycling aluminum cans are:
Students watch the video and read the information from the sites listed. I ask that they draw the life-cycle of their aluminum can to share with the class.
Students come back to the gathering place to share their life-cycles. I ask students how this might relate to the rock cycle.
I draw the aluminum recycling cycle onto an overhead transparency as students share theirs with the class.
http://www.rhinorecycling.co.za/cans.htm has a great image of the recycling cycle.
I place the overhead transparency on top of a poster of the rock cycle.
http://whs78science.weebly.com/uploads/1/2/9/6/12967592/rock_cycle.jpg has a diagram of the rock cycle that can easily overlay with the aluminum recycling cycle.
Make the connection between these two cycles for students. This provides a hands-on understanding of the rock cycle that is often difficult to understand, because it is not a process that is seen is practice.
I ask students what part of the rock cycle features weathering. Students come up with ideas about where weathering occurs in the cycle and give evidence for their assertions. Sediment is a weathering process, melting into magma is also a weathering process.
I assess students' group life-cycle of an aluminum can and how they explain the connections between the rock cycle and their cycle.
If students can explain it, even though they may not use the official terminology, I am satisfied that they understand the concept. What I am really interested in knowing is if students understand that weathering is a part of the surface change of the earth as well as part of the deeper rock cycle.
This assessment of the connections can be done either orally, during class discussion, or in written form in students' interactive science journals.