First, however, let's take a brief look at the children's picture book that inspired our activities: OH! The Things You Can See In The Dark! by Cathleen Francisco.
OH! The Things You Can See In The Dark! is a celebration of wonders that happen at night. Interspersed with natural marvels, like northern lights and fireflies, are human-made things such as hot air balloons and fireworks.
The first thing the reader notices are the unique illustrations. Set on a shiny black background, the lights and colors of the images emphasize the concept that darkness is almost never complete. The reader soon learns that there are many things to see after sunset.
The text is written in two levels, with lively short sentences accompanying the illustrations meant to be read by the child, and longer sentences and paragraphs on the other page that are meant to be read by older helpers.
You can get a sneak peek at the illustrations and some of the text at Cat Francisco's website. Or, pick up a copy and help a child explore the many marvels that can be discovered after dark.
Hardcover: 36 pages
Publisher: Self-published (2016)
About half of the animals on the planet are nocturnal, which means they are active after dark. This number may seem surprising at first, but remember, for example, moths are nocturnal and there are many more species of moths than their day-flying cousins, the butterflies.
Can you guess the nocturnal animals seen and heard in this video?
The Science of Light Pollution
When you look up into the sky on a clear night, do you see the Milky Way? If you are like roughly 80% of Americans, the Milky Way is no longer visible because of the light from streetlights, etc. Astronomers who study the night skies were among the first to notice the negative consequences of excessive artificial light, which is called light pollution.
Light pollution does not only effect humans. Lights from manufactured sources can disrupt the ability of nocturnal animals to find food, to reproduce, and to disperse or migrate.
Light levels effect the natural cycles called circadian rhythms. Animals exposed to high levels of light at times that are normally dark can have changes in hormones and activity patterns. They may sleep too much or sleep too little. They also may be ready to reproduce during the wrong season.
Animals that migrate at night often use the moon and stars to navigate. For example, newly-hatched baby sea turtles are attracted to the ocean via natural lighting cues. If there are too many artificial lights in the area where they hatch, they crawl inland and die.
Activity 1. Investigate Light Pollution
a. Check the internet for images of the Earth at night to see how much light is visible from space. (An example from NASA here).
b. With family or friends, take a walk or ride at night and look for sources of light pollution (Note: Safety first!). Keep your findings in a journal. Later you might want to write a report or blog post about what you find out.
Scientists studying light pollution have identified different types.
Urban skyglow: Refers to the brightening of the skies or "glow" that can be seen over cities at night.
Glare: Occurs when your eyes are hit with more light than they are able to process, for example when you are blinded by oncoming headlights when driving at night.
Light trespass: Describes when light extends into areas where it is not wanted or needed. A prime example is when a neighbor's porch light or street light shines into your bedroom at night, making it difficult for you to sleep.
Uplight: Just as it sounds, uplight is lighting that is directed upward towards the sky, where it does no good as illumination.
Clutter: The type of lighting that occurs when lighting sources are too bright and/or too close together. Most of the light is misdirected or unnecessary.
How many types did you find?
Learn about what changes can be made to lighting in your community to help lower light pollution.
c. Globe at Night is an International Citizen Science Project is looking for volunteers to help track light pollution by counting the number of stars you can see in various constellations.
Activity 2. Investigate Circadian Rhythms
Many natural processes cycle or fluctuate over 24 hours, often in response to changes in lighting. These cycles are called "circadian rhythms." Some processes that fluctuate include heartbeat, body temperature, sleep, and kidney output.
- Graph paper
- Timing device that counts seconds
Experiment: Take your resting heartbeat/minute every hour throughout the day, over several days. Plot the numbers on a graph and look for patterns.
To obtain your heartbeat for minute, use the first two fingers of one hand to locate your pulse at the wrist of your other hand. Once you have located the pulse, count the number of beats for 15 seconds. Convert to heartbeats per minute by multiplying the number you obtained by 4.
How do you think your results might change if you got up three hours later or went to bed three hours earlier?
For more great activities, see Five Biological Rhythm Experiments for Kids
See our growing list of children's books about nocturnal animals at Science Books for Kids.
Disclosure: This book was provided for review purposes. Also, I am an affiliate with Amazon so I can provide you with cover images and links to more information about books and products. As you probably are aware, if you click through the highlighted title link and purchase a product, I will receive a very small commission, at no extra cost to you. Any proceeds help defray the costs of hosting and maintaining this website.
And don't forget the Spectacular Summer Science Series.