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Hello Darkness: Light Bulb Moments for the Longest Nights of the Year

December 14, 2017 / by Meg Richard

There are many teachers who serve as sources of inspiration in our lives, but the one that we hope to emulate most is undoubtedly Professor Albus Dumbledore, of JK. Rowling's Harry Potter series.

During this hectic holiday season, as the days are shrinking but the pile of grading is not, we cleave to his wise words:

“Happiness can be found, even in the darkest of times,

if one only remembers to turn on the light.”

― J.K. Rowling, Harry Potter and the Prisoner of Azkaban

As Gretchen Vierstra recently pointed out, teaching in December can be tough.

Many of us find ourselves at school before the sun makes its grand appearance and are still there long after it quits for the day.

What is it that's causing the daylight hours to hasten by, providing us additional hours of darkness?

Is there a way to embrace the "Darkside" of the season, while still resisting the negative forces at work?

Whether you're looking for ways to get students engaged with the darkness around us during this time of year or enamored with the bright lights of the season, here are some tips and tricks to use around the solstice to help students embrace phenomena and enjoy the holiday season.

The Science of a Solstice

This time of year, it can feel like there aren't enough hours in the day to get everything done, and there's an astronomical reason for that feeling: the days are getting shorter (in the northern hemisphere).

The Earth, while approximately a sphere, isn't traveling in a perfectly vertical fashion. While many of us envision the North Pole -- Santa and Elves included, especially during the holiday season -- at the top of the Earth, the Earth is actually tilted approximately 23.5 degrees as it travels around its elliptical path. Due to this tilt, latitudes in the northern hemisphere are tilted toward the sun in summer and away from the sun in winter. This affects what part of the Earth is illuminated and, as a result, we experience fewer hours of daylight during the winter months. The shortest of these days is called the Winter Solstice (December 21st). The shortest day also means the longest night.


Embracing the Dark Side

Model It

We learn that the tilt of the Earth is responsible for the seasons and the change in the amount of daylight, but this can be a little tricky to visualize. Why not have students build and test models of how this is possible?

To model this concept, all you need are some flashlights and mini-"Earths" (balls). Using a ball to represent the Earth, you can show that as the Earth revolves around the sun (a flashlight), if the tilt of the Earth is kept constant, the amount of light changes depending on where you're located on the Earth’s surface.

  • Students can make observations of the model and then make inferences about what a person standing at different latitudes would observe over the course of a day as the year goes by.

(1-ESS1-1MS-ESS1-1, Crosscutting Concepts: Cause and Effect, Systems and System Models.)

Screen Shot 2020-03-09 at 1.28.54 PM

VIDEO: Claims, Evidence, Reasoning 

Collaboration Across the Continent

Latitude plays an important role in how much daylight different regions of the Earth receive.

  • As the solstice approaches, encourage students to record the sunrise and sunset times for their location and graph the number of daylight hours in a day.
  • Take to social media and have your students connect and collaborate with students from other locations to get comparable data points. Google Sheets and Google Maps can be shared between the student scientists for the weeks surrounding the solstice to help them visualize and make sense of the phenomena.

(1-ESS1-2, Crosscutting Concept: Patterns.)

As the seasons change, the angle of the sun in the sky will also change.

  • Students can track these changes in the length and direction of shadows and share this data with one another. If all of the groups have a common object such as a meter stick, data can be collected at the same time each day and compared with groups from across the nation.

(5-ESS1-2, Crosscutting Concept: Patterns.)

boxSeeing Without Sight

This time of year, we've all had those moments when you're looking at a package that you know you're not supposed to open, but you just HAVE to know what's inside. So you pull out every trick in the book, from shaking it at different speeds, to lifting it up and feeling around for any bumps or seams that might give you a clue to the secrets within. Why not capture that moment of curiosity with a mystery box?

  • Place some everyday objects in a sealed box. Have your students record their observations using their senses -- other than sight -- and make predictions about what's inside. Whether or not you tell them if they're right is up to you!

Going Batty

It’s hard to see in the dark, and yet some animals, like bats, have adapted to make the most of this environment. Students can use Go!Motion to understand bats’ echolocation.

  • Discuss how bats use high-frequency sound waves to generate pictures of their environments.
  • Then have students try it for themselves -- either blindfolded or using Go!Motion sensors. Go!Motion sensors emit sound waves and then "listen" for the reflected signal. By knowing the speed of sound and the time it took the return signal to reach the detector, you can plot the distance of objects vs. time.
  • Why not set up some obstacles in a box or your room and have students slowly turn around while using the probe to get a “picture” of what's in their area? You can have students either move around the room or use data provided by other groups to generate a model of the placement of objects in the room.

(4-LS1-2MS-LS1-8, Crosscutting Concepts: Systems and System Models, Cause and Effect.)

lots of bats


Embracing the Light Side

Wintergreen Sparking Candy

Wintergreen candies emit a blue glow when you eat them (a phenomenon that students can really sink their teeth into), and this happens for two reasons. First, as you break a sugary hard candy with your teeth, it emits a very small amount of UV light that the nitrogen in the air absorbs and then re-emits as light we can see. This is called triboluminescence, but it doesn’t explain why wintergreen flavored candies seem to work the best. The effect is a benefit of the flavoring itself: oil of wintergreen or methyl salicylate. Wintergreen oil absorbs UV light and when you chew the candy containing it, emits the light back as a visible blue light. Experiment with different types of hard candy and different brands flavored with wintergreen (Lifesavers, Altoids, Tic-Tacs, even gum), and record observations about which candy is the most shocking treat.

Black Light

Encourage students to examine the effects of black lights on different colors (items that are white or neon, appear to glow) and then to experiment with different substances (green plants emit a reddish glow as the chlorophyll reacts with the light). Students can even use their new understandings to communicate in secret messages using items that appear to be clear, yet react in the UV, such as petroleum jelly or tonic water.



No discussion about fun things that emit light would be complete without mentioning fireworks.

Bringing fireworks into the classroom may not be the best idea, but you can examine the metal salts used to color fireworks in a safe way.

  • Guide students to see how the electrons in various elements get excited when heated and then emit light of different colors as the electrons de-excite. Just make sure that proper safety guidelines are followed and that everyone is a safe distance away. By putting a small amount of the metal salts in ethanol and then carefully igniting them, you can show your students a dazzling array of colors (sodium: yellow; calcium: orange/red; strontium: red; copper: green/blue; potassium: purple/pink). These light emissions based on electron transitions in atoms can be tied into spectral line observations in astronomy and help students gain insights into how we know what composes stars and far away worlds.

(HS-ESS1-2, Crosscutting Concept: Energy and Matter.)

Examining the Nature of Light

What is light? Rachel Dixon shares some great ideas for helping your students think about how light works by constructing and testing models.

  • By examining how light interacts with objects such as mirrors, she helps her students try to figure out how to have eyes in the back of their heads.

(1-PS4-21-PS4-34-PS4-2, Crosscutting Concept: Cause and Effect.)

  • After exploring the concept of reflection, students can broaden their understanding and explore how light interacts with transparent and opaque materials of different colors.

(MS-PS4-2, Crosscutting Concept: Structure and Function.)

  • Have upper division students extend this activity to lenses, and then model how light is focused in the eye and how glasses help correct various vision problems.

(4-PS4-2, Crosscutting Concept: Cause and Effect.)

While science is a natural avenue for incorporating light and darkness, that doesn’t mean that the science department should have all the fun. Consider looking for ways to celebrate the changing seasons in any subject!

There is a light at the end of this wacky winter season in our classrooms. How are you going to make the most of the light or dark moments? Let us know in the comments below.

Interested in getting updates or connecting with the Teaching Channel Next Generation Science Squad? Sign up here:

Topics: Next Generation Science Standards, Science, Engagement, STEAM

Meg Richard

Written by Meg Richard

Meg Richard is a seventh grade science teacher at Summit Trail Middle School in Olathe, Kansas. She's been teaching science since 2010, and is a graduate of Central Methodist University and the University of Central Missouri. Meg is the coach of her school's Science Olympiad team and serves her district as a teacher leader. Meg is Nationally Board Certified in EA Science and was a 2019 Kanas State Finalist for the Presidential Awards for Excellence in Mathematics and Science Teaching (PAEMST). Meg is passionate about integrating authentic, hands-on science experiences for her students, and at times she can’t believe she is lucky enough to get to do the best job in the world: teach! Connect with her on Twitter: @frizzlerichard

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