Bright Time with Circuits
Lesson 3 of 4
Objective: SWBAT demonstrate how energy can be transferred from one object to another.
I begin this lesson by reviewing the terms potential and kinetic energy through a class discussion. I explain that today we will be experimenting with electrical energy. I ask students to make one or two sentences in their science notebooks about electrical energy being potential energy or kinetic energy.
Background: Batteries and hand cranks can be used to move electrons through a bulb to cause the bulb to light. For a bulb to light, you will need to create a circuit. The circuit must include a bulb, a battery and wire. (For this lesson, I used tinfoil because it was what I had available. I had to express to my students they needed to be careful because the tinfoil would get warm) The wire must connect the plus side of the battery to either the bottom or side metal on the bulb. The other wire must connect the the minus side of the battery to whichever metal side of the bulb was not touched earlier.
Students work with their learning partner for this lesson. I give each pair of students a container of materials that include four wires, two batteries, two bulbs, a hand crank and the appropriate holders.
I direct students to work together to light the bulb. When working together, students diagram their experiments and steps in their science notebooks. The inquiry aspect to this lesson is important. I do not instruct my students or give specific directions on how to light the bulb. In order for my students to take ownership of their learning and knowledge, it is imperative that I give students inquiry opportunities to experiment with materials in order to make sense of why and how the bulb lights up.
In this video you can hear students discussing what they tried and what they want to try next. The group members are struggling to make sense of the task and the materials I have given them. I resist the urge to tell them what to do in order for them to make sense of the science and concepts.
In contrast, this group also explains what they tried and how they revised their idea in order to get the light bulb to light.
When most groups are finished diagramming their steps and the experiment, I introduce the concept of electrical circuits.
I show students the parts of the circuits and how they work? Below is sample text of what I show and tell my students. Then students watch the video below for further circuit explanations.
Electrons with a negative charge, can't "jump" through the air to a positively charged atom. They have to wait until there is a link or bridge between the negative area and the positive area. We usually call this bridge a "circuit."
When a bridge is created, the electrons begin moving quickly. Depending on the resistance of the material making up the bridge, they try to get across as fast as they can. If you're not careful, too many electrons can go across at one time and destroy the "bridge" or the circuit, in the process.
At the conclusion of the video, I remind students that the energy from the battery is transferred from the battery through the wires and into the bulb.
After watching the video and discussing circuits, I give students another opportunity to refine their circuit systems from earlier. Students can keep their previous experiments or alter them. I also pose this question: Can you and your partner cause the bulb to light up brighter or make the bulb dimmer? I direct students to draw a model of their circuit in the science notebook as well as write about their ideas about making the bulb brighter or dimmer.
You can see in this photograph a student has written that the battery is connected (kenceted) as his hypothesis. This is a great example of a typical beginning of fourth grade science communication. It lacks details and specifics, however, it gives me a very good idea of what to teach in order to make better communicators of my students. Many of my students are not used to explaining their thinking in science and my science notebooks are a very new concept for them.
In this video you can see and hear a group of students talking about how they revised their ideas after watching the video.
After students are given a chance to experiment and refine their circuits, student volunteers present their demonstrations to the class. In their demonstrations students must explain to the class what they have learned about energy and how they were able to cause the bulbs to glow brighter and dimmer.
Students turn in their science notebooks at the end of the lesson. I use this assignment as a formative assessment not only for science, but also for writing. I can then design writing and science lessons to address class and student weaknesses and strengths.
Students work more the next few lessons adding more and fewer bulbs and batteries into the circuits to better their understanding of electrical energy.