Today’s Lesson Is…The Science of Fireflies

When you think about summer, several fond memories likely come to mind–ice cream, trips to the beach or lake, baseball, fireworks, barbecues, and…fireflies. It’s almost a rite of summer for kids to take jars or coffee cans outside on a warm evening to follow these glowing “lightning bugs” around, trying to catch them to create a makeshift lantern full of fireflies.

In Today’s Lesson, we’re going to learn some interesting facts about fireflies (including what makes their bottoms light up the night) and work on a fun, firefly-related activity!

Five Fun Facts About Fireflies

1. Fireflies aren’t actually flies. Yes, their name is a bit deceiving, but fireflies are actually beetles, and there are a number of different firefly species. A similar animal is the glowworm, a term that can apply to either firefly larva or wingless adult females. The difference between fireflies and glowworms is that fireflies have wings and glowworms don’t.
2. Bioluminescence gives fireflies their glow. If you’ve ever wondered what makes fireflies’ little butts glow, it’s a phenomenon known as bioluminescence. According to the Smithsonian Institution’s Oceans website, “bioluminescence occurs through a chemical reaction that produces light energy within an organism’s body. For a reaction to occur, a species must contain luciferin, a molecule that, when it reacts with oxygen, produces light. There are different types of luciferin, which vary depending on the animal hosting the reaction. Many organisms also produce the catalyst luciferase, which helps to speed up the reaction.”

Bioluminescent animals can control when they glow by regulating their brain processes and chemistry depending on their needs–whether it’s feeding or mating. Fireflies are far from the only bioluminescent animals–in fact, many deep-sea creatures are bioluminescent in order to survive the murky, pitch black waters of the deep ocean. Some well-known bioluminescent animals include squid, jellyfish, anglerfish, some species of sharks, and octopus.

3. Fireflies are very energy-efficient. If you’ve ever seen a light bulb’s packaging, you may have noticed its efficiency rating, which measures how much heat is used to produce light. For example, an incandescent light bulb is only 10% efficient, meaning that 90% of its energy is lost as heat (only 10% used for light). The bioluminescence in a firefly, on the other hand, is nearly 100% efficient, meaning that fireflies use very little energy to produce their light.
4. Their diet is…interesting. Firefly larvae actually disable their prey before feeding by injecting snails, worms, and slugs with a numbing chemical. Once fireflies reach adulthood, they eat nectar, pollen, and even other fireflies.
5. A firefly’s life expectancy isn’t very long. Most fireflies can survive for a couple of months in the wild. However, their population may be on the decline, as their natural habitats (fields, forests, meadows, etc.) continue to be decimated by development. Fireflies can be found on every continent in the world besides Antarctica.

Make Your Own Firefly!

With the help of Green Kid Crafts, we’re going to show you how to make your very own light-up firefly! While this craft obviously can’t re-create bioluminescence, it will demonstrate how it works as you also learn about electricity! Here’s what you’ll need:

• Conductive tape
• 3V button battery
• LED light bulb
• Black paper
• Yellow paper
• Glue
• Scissors

Once you have your materials, it’s time to get to work.

1. First we’ll cut the black and yellow paper into the parts of a firefly. Cut one large oval for the abdomen and thorax areas from the yellow paper. Cut a second large oval from the black paper. Then cut that oval in half to make the two wings. Finally, cut a circle from the black paper for the head.
2. Glue all the parts together to make a firefly. Round out the wings with scissors.

3. Push the LED light bulb through the abdomen, leaving the light bulb on the winged side of the firefly and the wires on the underside.

4. Flatten the wire prongs on the LED light so they lay against the paper.

5. Now for the electric circuit…the light bulb has a long prong (the positive side) and a short prong (the negative side). Make two paths with the conductive tape, one from each prong–the paths can grow closer and overlap at the bottom. Place the 3V button battery positive side down on top of the path leading from the positive prong. Tape the path from the negative prong on top of the battery. Do not let the two paths touch each other.
6. When the battery is attached to both paths, the firefly should light up!

So, how did the firefly light up? Well, electricity can flow from one place to another along a path. A circuit is one such path, which is closed…almost like a loop. In this craft, the electrical circuit was created with the conductive tape, LED bulb, and the button battery. Here, the tape acts as a path for the energy, so when the battery is placed on the tape, energy flows from the battery, along the path, through the wires on the light bulb, back to the battery, thus completing the circuit. If the battery or light bulb is removed, the circuit is broken.

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