Light Up the Holidays with Circuits!

Yah! You have received your freebie below, and we will also email you a link to access it later if you need to. We hope you enjoy since the holiday season is upon us! Can’t you just hear the songs, smell the fresh eggnog, and see the glistening snow? We love the holidays here at Growin’GEERS, so we wanted to equip you and your elementary GEERling with a mini electrical engineering lesson filled with holiday cheer!


This mini lesson is to have your student dissect a strand of Christmas lights to determine if a Christmas light circuit is in series or parallel.

Items Needed:

1. Electrical Outlet
2. Strand of Christmas lights you don’t care about damaging

We recommend a short strand to make it easier for your student to see the major connections.

Background on the Activity:

First and foremost, please be careful while the strand of lights is plugged in. We don’t want any GEERlings getting hurt! What we want to learn about in this activity is the difference between a series circuit and a parallel circuit. First though, let’s review some basics about a circuit in general.

A simple circuit must have three parts:

1. A power source - Christmas lights connect to a power source using a plug on one end.
2. A conductive path - Wire is usually the conductive path, but in this case, it is covered with a non-conductive green coating to prevent burning down your Christmas tree!
3. A resistor which uses the electricity to do work - The actual lights on the strand.

Our strand of Christmas lights is a series circuit, but this is what we want our GEERlings to figure out on their own. So, we are going to go over some details about series and parallel circuits, and walk through a way to investigate your strand of lights to help your student reach their conclusion. We have also provided a GEERling’s worksheet that provides a decision tree to walk them through a few questions to reach their conclusion!

So, on to series and parallel!

Details on Series and Parallel:

When lightbulbs are in parallel, each lightbulb has its own path to the power source. So, if one light doesn’t work, it doesn’t affect any of the other lights because they have their own connection to power.


When lightbulbs are in series, there is only one path for the current to flow through. If any part of this circuit does not work, the entire circuit will not work because the current is flowing from the power source through each lightbulb to the next. If any of them are broken, the circuit will not continue on.



Steps To Complete Lesson:

Below are the steps we recommend to take with your student as they walk through their worksheet to help them solve the problem.

Examine the plug that plugs into the wall. Ask your student how many wires are coming out of the plug. As you can see, there are two which adds a little complexity to our problem, but is actually very interesting.


Examine where those two cords go. This is why we recommend using a short strand so that your student has a chance to unwind the cords to see where they go. One leads to the first bulb and the other leads all the way to the end plug that is built to connect to another strand of lights.



The additional wire is an added piece with Christmas lights, and it is not necessary to complete this circuit. It only allows for the next strand of lights to receive power.


Examine the first light. You will see that it is one of only two lights in the entire strand that has one wire coming in and two wires coming out of the light. This is the beginning of the series. Each wire serves its own purpose: the one coming in connects to the power source, one of the wires coming out is to connect the power source to the next light, and the other wire coming out is to connect to the last light in the strand and complete the circuit.


Examine the second light. You will notice it only has a wire coming in and a wire coming out.


Try taking a bulb out and putting it back in. Talk to your student about why they think that might have happened.

Student Worksheet:

Click here to gain access to a worksheet to help your student through the activity. It asks questions that lead your child through a few questions to decide if the light strand is in series or parallel. Here is the answer key for the questions that were asked.

Want more details about series and parallel in regards to Christmas lights? This article is even more detailed for our high level learners!

Have fun, and enjoy learning throughout the holidays!

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