Students have spent several lessons examining a real life problem of pollution in their community. They have posed and created a real solution to the problem, but now I want them to move into the imaginary realm of a solution. What if there were no limits and they could create any kind of cleaning tool they could imagine?
Engineers think about function, shape and durability when they design solutions to problems. In this lesson I want to introduce students to the idea of shape and function as they design and share a totally new solution to the pollution problem.
You will need several similar items for students to test as they think about why shape and function and durability should be considered in creating a useful solution. The testing of strength and shape are part of the K-2 NGSS for engineering.
I begin today's lesson by bringing students together on the rug. I have 6 different types of pencils in the center of the rug. I say, "do you think all of these pencils are the same?" (no) "How can you tell?" (they are different sizes, different colors, some regular and some mechanical, have different designs, etc.)
"Do you think they all work the same way?" (answers are mixed here) "What might I do to see if they all work the same way?" (test them, use them, ) I acknowledge the ideas that students have and then say, "Can you predict which pencil will last the longest without the lead breaking?" (answers vary). "Let's take a vote on which one will last the longest without the lead breaking. I am going to hold up a pencil and if you think it will last the longest raise your hand. We will put the pencils in order of the most to the least votes."
I hold up the pencils and students vote for which one will last the longest. We put them in order on the rug. Now I say, " How could we test our votes, or our predictions?" (use them, color with them). "How might we do that?" (Let people try them.) "Should we have different people using the pencils or just one person?" (answers vary).
I am trying to walk students through the design of a science experiment with the pencils. I want them to test the pencils for strength and durability. This introduces the engineering standard for testing a material, and it will support the science practice of designing and carrying out an investigation.
I ask students, "Can you tell why you think it should be one person, or different people?" I take suggestions and then ask students to evaluate the reasoning based on how we would get the best answer about which pencil is the strongest. I support the general consensus about which way to proceed and justify it scientifically such as, if only one person uses all 6 pencils we know that they hold the pencil the same way and probably use it the same way each time, or if 6 different people use the pencils to color the same page we can observe all at once if the pencils are being used the same way.
We agree on our method and already have our prediction so I ask students, "are we ready to test the pencils now?" "How are we going to know which one lasts the longest?" (count, time them) "Which would be better? (using a timer because it doesn't get faster and slower like we might). Now I give the student tester a page to color with the pencil. I ask them to lean down hard on their pencil to make the drawing as dark as they can. I ask the timers to get ready and then I say "go!" We watch until a first pencil breaks and then record the time. We continue to time the rest of the pencils and then record our findings on the easel beside our predictions. (The hope is pencils break pretty quickly so students do not have to sit too long watching the process.)
"How did we do?" I ask students to think about how our predictions matched or did not match the outcomes. I want students to first think about what happened. Next I move into the idea of shape and durability of the tool (the pencil).
I ask students to return to their seats. While they are moving to their seats I quickly move the pencils in order of breaking time and tack them to the board. Then I ask, "why do you think one pencil might break more quickly than another? I am going to have you turn and talk to your table about why you think one pencil lasted longer than the others. I am giving each of you 1 talking cube and I want each person to share one idea. You can add your cube to a tower in the center of your table. When we are done, everyone should have added his/her cube to the tower." I use this strategy to encourage all students to engage in scientific discussion.
After about 5 minutes of discussion I ring the bell and ask for the group to come back together. I ask if someone would like to share what his/her table discussed. I try to reinforce students who bring up the strength of the lead, the shape of the pencil, etc.
I ask, "do you think that some things are made stronger than others even when they look alike? Can anyone think of something they owned that might have broken because it wasn't strong enough?" I let students share their stories of broken toys.
"So do you think that how strong an object is might help it last longer? Why do you think so?"
After students have shared their thoughts I hold up a ladle and a spoon. I say, "I have 2 different types of spoons here. Which one I might use to serve soup. I ask them, "why do you think one would be better than the other?" (It is bigger, it would hold soup better, etc.) "Is one spoon stronger than the other?" (We don't know, maybe). "Right, we don't know, but we do know that while they are both spoons, one would be better for soup because of its shape. Shape and strength are 2 things that engineers think about when they are designing things to solve problems. Shape like the right spoon, and strength like the strong lead."
"Today I would like you to imagine that you could build anything you wanted to clean up the pollution at the beach. You are the designer. You want to think about strength and shape as you design a tool or machine to clean up the beach pollution. When we made posters and a video, we designed something we could actually do, but what if we could make anything we could imagine. What might you make? Think for a minute about our pollution problem. Can you think of a tool that someone could use to clean things up? What shape would it be? Why would you pick that shape? What would you make it out of? As you draw today, think of these things and fill in the form to attach to your picture. Are there any questions about what you will be doing?"
I hand out paper and a form Outside the Box Form with the questions and I circulate around the room helping students to fill in the form while they are drawing. Designing Outside the Box An Outer Space Design Filling the form to show what the invention is made out of Shape and Materials
I collect the student work and after school I hang it in the hall with the forms attached. The next day I invite students to visit our design gallery. I tell them, "Sometimes people see a problem and they invite engineers to create a design to fix the problem. The people then pick one design and find a factory to build it. Today we will be the ones who look at the designs. We are not going to pick a favorite of the class but you will think of your own favorite and why. Each one of you will think about what you would pick if you had to pick one. You may look at each design and see what other people have created. Remember to check out the shapes and materials that your classmates have chosen."
We visit the display of drawings to honor all of our work. When we return to the classroom I say, "we have worked hard as engineers. We have created a real solution to the problem that we could do, and we have now made our imaginary solutions.
Before we are done today I would like you to write about which design, other than your own, you might pick to build if you were the factory owner. Tell which one, what was it called, and why might you pick that one. (I know many students would like to pick their own, so I ask them to really look at someone else's design for this part of the lesson.)
I collect the writings to look at how students have viewed the solutions to the problem and to see if they are reflecting on the designs more like an engineer, i.e. how the design solves the problem, or if they do not really understand how an engineer might reason. I am looking for something like, I picked this design because it would be a good way to clean up the pollution in the beach.
Are there any things you would like to share about the real or the imaginary solutions, or about being an engineer?" I let students share their final thoughts because it is important to bring closure to a lesson and the ideas that it may have raised.