The Physics of Christmas Lights

Christmas lights are the most noticeable symbol of the holiday season. These sparkling lights seem to warm up the coldest of December nights and give an exciting glow to the home. Even though we are so familiar with Christmas lights, there is a bit of background physics that can give you the edge to your holiday cheer. All of us heard the words "voltage" and "current," but the difference between the two might be slipping through our fingers. Voltage is the electrical energy that we can use between two parts of a circuit and current is the number of electrons flowing through a wire. In circuits, the current needs material to flow the electrons through. When we plug in our Christmas lights, it’s only the current that changes. The more light bulbs we put in a Christmas light’s string, the more festive the mood it brings. There are two ways to set up lights in a circuit: in series or in parallel. A series circuit has bulbs set up one after another on a wire. A parallel circuit looks like a ladder with the bulbs in the middle of each rung. This is the basic physics behind Christmas lights.

Our very own Year11 physics students have explored it themselves. It is one of the best and exciting experiences they have in studying electric current and circuits. They have learned how to connect the bulbs in a series and parallel circuit. On the other hand, Y10 students have learned about making measurements, describing motion, forces, and motion, turning effect of forces, and forces and matter. Year 12 students have learned about measurements and uncertainties, vectors and scalars, kinematics, accelerated motion, dynamics, forces, work, power and energy, momentum and impulse, thermal concepts, and modeling a gas. Key Stage 3 Science students have learned about food and digestion, plants and nutrition, material properties, states of matter, energy changes, elements and compounds, measuring motion, mixtures, and energy resources: its practical uses and safety measures in homes.

We might have heard the joke that the Christmas lights are put up to help Santa Claus find our house and easily locate the tree in order to put presents under it, but the Christmas lights also have a more meaningful symbolism. So, in time for this season, I would like to bring everyone back to the fascinating Christmas lights that we have in our homes. May these Christmas lights serve to remind us of good and happy memories that we have with our families, friends, and loved ones.