Hey there! Have you ever seen something amazing outside when it’s dark? Maybe you’ve watched fireworks or a big, bright full moon. Well, today we’re going to talk about something else that’s super cool to see at night—fireflies!
Our friend Siddharth has a great question: Why do fireflies glow? Have you ever seen these little glowing bugs, also called lightning bugs? When I’m camping, I love watching them light up the fields near my tent. But guess what? Their light isn’t from fire, lightning, or even light bulbs. It’s a special light made inside their bodies!
Fireflies have special chemicals in their bodies that mix together to create light. Scientists have even figured out how to make similar chemicals. When these chemicals mix, they glow! Isn’t that amazing?
Have you noticed that fireflies don’t just stay lit up? They flash their lights on and off. But why do they do that? Well, scientists are curious about this too. Fireflies don’t think like people, so scientists observe them to understand their behavior.
When you watch a group of fireflies, their flashes might seem random. But if you focus on one firefly, you can see it flash every few seconds as it flies around. Sometimes, another firefly will flash back, and they keep flashing back and forth. Then, they might meet up!
It turns out that flashing helps fireflies find each other in the dark. The fireflies flying around and flashing are usually males, and the ones flashing back from the grass are usually females. It’s like the males are saying, “Hey, look at me!” and the females reply, “I see you, come over here!”
Scientists call these flashes “signals.” Different kinds of fireflies have their own unique flash signals. There are over 2,000 different kinds of fireflies, each with its own special signal. By flashing their unique signal, males can show what kind of firefly they are, and females can recognize and respond to the right signal.
You can learn to recognize firefly signals too! There are charts that show the timing of different signals. Scientists are still discovering new signals and even some fireflies that copy the signals of others. How wild is that?
Fireflies create their own light by mixing chemicals inside their bodies. Their flashes might seem random, but they’re actually signals that help fireflies of the same kind find each other. Thanks, Siddharth, for asking such a great question!
Stay curious, and keep exploring the wonders of the world around you. Who knows what amazing things you’ll discover next!
Firefly Light Experiment: Let’s create our own “firefly light” using simple materials. You’ll need a small jar, a glow stick, and some black paper. Break the glow stick to activate it, then place it inside the jar. Cover the jar with black paper, leaving a small window to see the light. Observe how the light glows in the dark, just like a firefly! Discuss with your friends or family how this light is similar to and different from a firefly’s glow.
Flashlight Signal Game: Grab a flashlight and a friend or family member. Take turns being the “firefly” by using the flashlight to create a pattern of flashes. The other person should try to copy the pattern. This game helps you understand how fireflies use light signals to communicate. Can you come up with your own unique signal pattern, just like different kinds of fireflies?
Firefly Observation Journal: If you have a chance to see fireflies at night, take a notebook and pencil with you. Watch the fireflies and try to notice any patterns in their flashing. Write down what you see. Do some fireflies flash faster or slower than others? Share your observations with your class or family. This activity helps you become a scientist, just like those who study fireflies!
Sure! Here’s a sanitized version of the transcript:
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(phone ringing) – Hey, it’s Esther. What’s the coolest thing you’ve ever seen outside after dark? Maybe it was fireworks or a full moon. These people are getting ready to watch something you can only see when it’s dark. If you can, you might want to pause the video now and turn the lights off to watch too. Check it out. Someone named Siddharth has a question about what’s making these flashing lights. Let’s call Siddharth now. (phone ringing) Hi Siddharth.
– I have a question for you, why do fireflies glow?
– Great question. Did you guess that those lights were fireflies, or you might call them lightning bugs? Maybe you’ve even seen some in person. When I’m camping, I’ve watched them in fields near my tent. Even though they’re called fireflies and lightning bugs, this isn’t light from fire or lightning, and it’s not from light bulbs either. This is light you can catch. Up close, you can see that this is an insect. Do you notice how these parts look different? Light can shine through them, like this. The light shining through is actually made inside the firefly’s body. Different chemicals in its body combine to make light. Scientists have been able to create similar chemicals. Watch what happens when they mix two. Whoa, so each light you see here is a firefly combining chemicals in its body. How amazing is that?
You may have noticed that fireflies don’t stay lit up. Instead, they flash their lights on and off. But what’s all this flashing about? I’m curious, what do you think? What are fireflies doing when they flash their lights? Now it’d be a good time to pause the video and discuss. Okay, you ready? This is a question scientists are curious about too, and it’s a hard one to answer. Fireflies don’t think and act the way people do, and we can’t really think like fireflies. That’s why scientists start with what they can see and measure, their observations, to better understand what fireflies might be doing.
When you watch a group of fireflies, their flashes can seem random; it’s hard to keep track. But what if you focus on one firefly? You can see where it flies and when it flashes. Now, it’s difficult to film fireflies in the dark, so we’re going to have to switch to a drawing. But what you’ll see next is based on real observations of some fireflies. Okay, here’s our firefly. Watch how it flashes every few seconds as it flies along. Our firefly keeps circling back to one area. And look, did you see the flash below? There’s another firefly down on the grass. Our firefly keeps flashing, and now the other firefly has started to flash too. They keep flashing back and forth. Then, something new happens. Our firefly flies down and lands next to the one in the grass. This is something scientists have observed many times. A firefly flashes as it flies around, another flashes back. They flash back and forth, then the two meet up.
Maybe you guessed earlier that flashing helps fireflies find each other in the dark. And you’re right, that seems to be one reason why fireflies flash. Through their observations, scientists have also learned that the ones flashing as they fly are usually males. The ones flashing back from the grass are usually females. It’s like the males are flashing, “Hey, check me out,” and the female flashes back, “I see you, come over here.” A firefly’s flash is a way to send a message; scientists call that “a signal.” By observing many different fireflies, scientists noticed a curious thing about these signals. Some male fireflies make a short flash every few seconds. Other males fly upwards as they flash, making soups of light. And remember those people we saw? They’re watching males that match up their flashes so they can look like ripples of light.
Wow, scientists now think that different kinds of fireflies have their own unique flash signals, and there are over 2000 different kinds of fireflies. That’s a lot of signals. By flashing their unique signal, males can show, “Hey, I’m this kind of firefly,” and females of the same kind can recognize that signal. They flash back just at the right time to answer, “I’m the same kind of firefly too, come over.” You can learn to recognize firefly signals too. There are flash charts like this that show the timing of different signals, and scientists continue to discover new flash signals as well as other ways that fireflies use their glow. They’ve even found that some kinds of fireflies are flash fakers. In addition to their own signals, they sometimes copy the signals of other fireflies. That’s wild.
So in summary, fireflies can make their own light by combining chemicals inside their body. Even though their flashes might seem random to us, they’re actually signals that help fireflies of the same kind recognize each other and meet up. That’s all for this week’s question. Thanks, Siddharth, for asking. Now for the next episode, we reached into our question jar and picked out three questions sent into us that we’re thinking about answering next. When the video’s done playing, you’ll get to vote on one. You can choose from, “Who invented erasers?” “How do you fix a broken heart?” “Why is ocean water cold?” So submit your vote when the video is over; we want to hear from all of you watching. There are mysteries all around us, stay curious, and see you next week.
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