Building Circuits

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Objective

SWBAT construct a circuit and explain the differences between a closed circuit, open circuit, and short circuit.

Big Idea

How can you construct a circuit to light up a lightbulb with just one wire and one battery?

Introduction

10 minutes

I had students insert the Circuits Investigation Sheet into their science notebooks, and answer the first question.  I reminded them this is just their initial understanding, and there are no wrong answers.  I explained that they would be creating as many circuits as possible using just a lightbulb, an insulated wire, and a battery.  (By using the vocabulary throughout the unit, it will be easier for students to acquire the vocabulary when it is more formally introduced.)

I then wrote "Lights Up" on one side of my whiteboard, and "Does Not Light Up" on the other.  I built a circuit that did not light up (one wire from the top of the battery to the side of the lightbulb base), and drew it on the "Does Not Light Up" side.  Many students tend to think they should only draw their successes, but they need to draw both in order to draw conclusions and find patterns.

I had them set up a chart in their notebooks so they could record each trial as well, and then called up a partner to collect materials.

Engagement

30 minutes

Even though many students claimed to have remembered this from 1st grade, even the fastest pair took several minutes to light up the bulb.  I just kept encouraging them to be persistent and to look at all the things they drew that did not light up the bulb and look for patterns.

Once the first group figured out a way to light the bulb, it spread pretty quickly, so I had them look for other circuits they can build that light the bulb.  Before their enthusiasm slowed, I had students come up to the board to draw both working circuits and circuits that did not work.  This was a subtle way of helping some pairs along.

Closure

10 minutes

I asked them to share what patterns or rules they noticed.  They knew you had to have metal touching the top and bottom of the battery, and the bottom and side of the base of the light bulb.  I then had them return their materials, and add definitions to their investigation sheets.