Lesson 5 of 11
Objective: Students learn about completing circuits and how energy travels through a conductor taking the path of least resistance.
Today's lesson takes some preparation. Cooking the conductive dough, stirring up the insulator dough and getting the battery packs all ready, takes some time. All of the resources and materials for this lesson are listed in this University of St. Thomas website. Follow their website, look at their helpful videos and use the recipes for the doughs exactly to be successful! I used lemon juice in the play dough instead of cream of tartar and was sure to mix the dye into the water before adding it to the dry ingredients. It worked just great! Allow about an hour to get ready.
Playing with electricity using dough will totally rock my student's world! I was really excited about this lesson! Before we began the investigation, I wanted them to reflect on yesterday's lesson, so I asked them to come and sit in front of the SB with their notebooks. Their reflection was key to helping them remember concepts they would need to apply today. After they were settled, I brought up three video clips that really showed some great critical thinking and understanding from yesterday's lesson. This refreshed their memory better than anything I could have said as they could see their classmates explaining understanding of a a complete circuit. I think that shooting video footage of students while they are learning is a great way to show them what great things they are doing and saying. It helped them see themselves as learners as well as help them remember what a closed circuit is.
After we were done, we reviewed how electricity travels. I told them that we would be entering the lab and conducting another investigation to help them understand that electricity travels through more than just wires.
I had the lab ready with: One KLEWS Chart for each pair of students, a cup of multicolored LED 10 mm lights, 1 battery pack for each pair of students, enough sugar dough in baggies for each pair, several balls of conductive salt dough in baggies for them to be able to choose their colors.
I had my students gather their iPads, science notebook and their pencils and head to the lab. I had started the lesson in my classroom because I knew that the excitement was going to be a lot to reign in once we entered the lab and they realized they would be working with some really cool materials!
I asked them to grab a KLEWS Chart and find a place to sit within their table groups. After they were seated, I opened up the Creative Circuits SB File to the first page. We reviewed each page, went over materials and the important rules about the LED lights. Then we discussed the Driving Question again: Can electrical energy that is transferring from place to place be changed?
Modeling: Using a colored ball of dough, sugar dough, 1 battery pack and a few lights, I modeled how the circuitry would work by creating two snakes and plugging the battery pack's red wire and black wire in the ends. Then I plugged in an LED light by straddling it across the dough, making sure that the longer leg was plugged into the red wire's side of the dough snake. It lit brightly and the whole place went up for grabs! The gasps and "ahhhhs" made me smile! They were so amazed! Unlike yesterday's lesson, this lesson needed to be modeled first because just turning them loose with the materials could damage the lights.
We talked a little bit about how they thought it worked. I added the sugar dough in to demonstrate that the insulator slows down or stops the flow of electricity. I told them it was their turn to experiment now but to remember NOT to plug the light into the battery pack directly as the SB file said.
Work in Pairs: I partnered up students according to how well they worked together on other occasions. I have learned that in a lab, certain students really excel when paired with the right person. I instructed them to gather 1 cup of LEDs, 1 baggy of sugar dough and one baggie of colored dough and then return to their seats. I told them they could begin their work! I told them that they needed to start to fill out their KLEWS chart. I left he SB file up on the first page with the driving question for them to see.
I roved the classroom observing my students as they worked and directing groups to label and use their KLEWS chart for their observations. I asked questions and played with them, experimenting with shapes. They were excited to see that even with different shapes, it works as long as the circuit is complete. Two boys demonstrated that there were different colored lights even though they thought they were all white. We can see in the clip how the direction of the bulb placement was essential for it to light up. At one point, I asked "why is the bulb dimmer?" They learned that as the insulator was placed in the circuit, the lights dimmed and as there were more.
We discussed different possibilities. One student called me over to show me how she could get the light lit by plugging it into the battery pack. It blew! And then she remembered. I reassured her that that is how we learn. She would be one student I would call on when we talked about the dough creating resistance. We tried to make the sushi roll, but had a harder time getting lights to light. Finally, with some careful manipulating, the lights lit into a wreath!
We talked about how we do get some dimmer bulbs from the white sugar dough. I had used distilled water to make the dough, however some current still ran through it. I explained that it wasn't completely insulating the current, but still allowed less current to flow through.
At one point I stopped them, gathered them around me, and rolled another little snake and placed it between the wires and the bulbs. The bulbs went out because it took the path of least resistance. but instead of just telling them, I questioned them carefully to get them to understand why this was happening. I prodded them to think about it logically. It was fun to see them model what I did and then understand it! Students struggled to make sense of the wires and connect it to yesterday's investigation.
After about a half hour of playing with dough and lights, it was time to stop and share our thinking.
Wrapping It Up!
Needles to say, no one wanted to stop! Students were anxious to talk about what they found out. I sat down with them to discuss their findings and talk about what they understood.
I asked them if they thought we answered the Driving Question? We discussed what we predicted about how electrical energy transferred from place to place, and that the snake we placed across the two snakes is evidence that the path can be changed. But, what about the energy itself? I was helping them understand how the dough breaks down the strength of the electrical energy and one student shared that she never knew that dough would make light bulbs light up. I explained that the dough allowed the light to light because I wanted her to remember why we don't plug the light into the wire without the dough. As we talked, she started to understand how the dough slows down and/or insulates the energy to the bulb, keeping it from blowing out.
These questions and discussion moments are essential so that students can absorb the information, critically think and tell about it. After all the excitement, they needed a good amount of time to focus on what the investigation helped them discover. After all was said and done, we all agreed that yes, the Driving Question had been answered. Indeed electrical energy can be changed when it moves from place to place.