In this introductory lesson of the unit students are tasked with developing questions about electricity generation as they try to use a lemon to light an LED.
This lesson aligns to the NGSS Practices of the Scientist of Planning and carrying out investigations because students are investigating how to make a lemon into a battery.
It aligns to the NGSS Crosscutting Concept of Cause: Mechanism and Prediction because students will try to explain the relationship between the lemon and the electricity as they begin to think about the smaller scale mechanisms that lead to a lighted bulb.
This lesson also aligns to the HS-PS1-2. HS-PS1-2. Construct and revise an explanation for the outcome of a simple chemical reaction based on the outermost electron states of atoms, trends in the periodic table, and knowledge of the patterns of chemical properties because it is the outermost electrons that are responsible for making the light bulb light.
There is no prior knowledge or skills needed for this lab.
The following materials are needed for this lesson:
Every one of my classes starts with a Do Now. The goal of this section of class is to get students settled and launched into the learning experience for the day. Today, they will make a battery out of a lemon, and so I have asked them to read the The Lemon Battery Lab procedure and be ready to put the procedure into their own words.
This work focuses on the CCSS Reading Standards for Literacy in Science and Technical Subjects 6–12 by giving students the opportunity to "3. Follow precisely a complex multistep procedure when carrying out experiments, taking measurements, or performing technical tasks..."
During this direct instruction period I randomly call on students to ensure that students understand the procedure. I then talk about the NGSS Practice of the Scientist known as asking questions. I remind students that while getting the LED to work is great, more important to me is the quality of the questions that students ask during this introductory activity. I tell them also that I do not plan to answer many questions today.
I ask that students play a role in their group. The roles can rotate so that everyone can get a turn trying to make the LED light. The roles are:
During this part of the lesson I have a good time working the room.
Every time a student asks me a questions I offer praise for the question, and express my own (feigned) uncertainty as to the answer. I offer students moral support when their LED does not light, and model what tinkering and wondering looks like if they have run out of steam. Students who have gotten their LED to work are encouraged to make the LED brighter, or to find somehthing else to "mess around" with, such as using different or more pieces of metal. If a student is really frustrated and has "tried everything" I might use a multimeter to see if any electricity is being generated.
However, it really does not matter to me if every LED gets lit--what I am trying to do is make sure students sense of wonder is being lit. During this time I make a point of asking students what they have observed. All questions and observations are pooled into a group's Lemon Battery Questions and Observations form.
Two different groups' completed forms are available for you to view. Group 1 did not get it to light, while Group 2 did. Both groups asked good questions and made some interesting observations. With that said, students did always get excited when their LED lit up--and so did I!
In this trying and failing video I am reminded how important it is to let students experiment and experience the frustration from failed attempts. In this taking it further video, I am reminded that a true scientist finds a question in the previous question's answer.
During this part of class I facilitate a whole class sharing of the questions students created. A few times I had to interrupt the conversation to get it back on track because students were moving toward offering answers to the questions that other students posed. I noted that while this is a natural progression, I wanted students to do this activity on a subsequent day. It was clear from the conversation that students are interested in this topic.