Hi there! Imagine you’re walking through a forest. You hear a tree frog chirping nearby and a wolf howling in the distance. Even though both sounds might seem loud, the wolf is probably much farther away than the frog. This is because howls can travel long distances, but it’s not just about being loud. In fact, a gray wolf and a gray tree frog make sounds at about the same volume. The real difference is in how these sounds travel through the air.
All sounds are made up of waves that move through the air and vibrate parts of our ears. When a frog chirps, the sound waves are short and close together, creating many waves per second. This is called high-frequency sound. On the other hand, a wolf’s howl has long, spread-out waves, which means fewer waves per second, known as low-frequency sound.
The frequency of a sound wave affects how far it can travel. High-frequency sounds, like a frog’s chirp, don’t travel very far because they lose energy quickly as they move. They also tend to bounce off obstacles like trees or buildings. Low-frequency sounds, like a wolf’s howl, can bend around obstacles and keep their energy longer, allowing them to travel farther.
Think of it like ocean waves hitting the shore. Long, rolling waves can flow around the coast, while short, choppy waves get interrupted. This is why animals that need to communicate over long distances, like wolves, elephants, and whales, use low-frequency sounds. For example, elephants can communicate with rumbles that are so low humans can’t hear them, reaching up to 10 kilometers away. In water, sound travels even farther, so some whales’ songs can be heard over a thousand kilometers away!
High-frequency sounds are still useful in certain situations. Animals like bats and dolphins use them because these sounds bounce off small objects like insects or fish, helping them find food. This is called echolocation.
Whether using high or low frequencies, the goal of animal communication is to make sure the sound reaches the right ears. Now that you know a bit about how sound waves work, you might wonder how to stop them. For that, you can explore more about sound waves and other science topics with Brilliant, the sponsor of this video. Brilliant offers fun and interactive lessons on science and math concepts, like how waves travel and interact.
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Gather some materials like a tuning fork, a rubber band, and a ruler. Strike the tuning fork and place it near your ear to hear the sound. Then, stretch the rubber band and pluck it to observe the vibrations. Discuss with your classmates how these vibrations relate to sound waves and frequency. How do these activities help you understand why a wolf’s howl travels farther than a frog’s chirp?
Work in pairs to create a simple experiment using a smartphone app that measures sound frequency. Take turns making different sounds and measure their frequencies. Then, test how far each sound can be heard by moving away from your partner. Record your findings and discuss which sounds travel the farthest and why.
Create a set of cards with pictures of animals on one side and their typical sound frequencies on the other. Mix them up and play a matching game with your classmates. Match the animal to its sound frequency and discuss why certain animals use high or low frequencies for communication.
Use art supplies to create a visual representation of sound waves. Draw or paint the difference between high-frequency and low-frequency sound waves. Display your artwork in the classroom and explain to your classmates how these waves relate to the sounds made by frogs and wolves.
Use an online simulation tool to explore how sound waves travel through different environments. Experiment with changing the frequency and observe how it affects the distance the sound can travel. Share your observations with the class and relate them to the communication methods of different animals.
This video is sponsored by Brilliant. Hi, this is Kate from MinuteEarth. Imagine you’re in the forest and you hear the chirp of a tree frog and the howl of a wolf. The good news is that the wolf is probably much farther away from you than the frog—howls can travel a long distance. However, it’s not because wolves are louder; a gray wolf and a gray tree frog actually call at about the same volume. The difference lies in how the sounds behave, which has significant implications for why some animals chirp and others howl.
Both sounds—like all sounds—are waves of pressure that vibrate parts of your auditory system. In a chirp, the waves are short and compact, resulting in many waves per second, while in a howl, the waves are long and spread out, leading to fewer waves per second. This characteristic, known as the wave’s frequency, determines what a sound sounds like; high-frequency waves are high-pitched, and low-frequency waves are low-pitched.
A wave’s frequency can also affect whether it reaches your ears. High-frequency waves are not good at traveling long distances. As a wave propagates, it releases energy as heat, and the more frequently a wave oscillates, the more energy it loses, causing it to fade out over a shorter distance compared to a howl of equal volume. Additionally, low-frequency waves tend to bend around obstacles—like trees or buildings—while high-frequency waves are more likely to reflect off them.
This is similar to ocean waves hitting the coast; long, rolling waves flow around it, while short, choppy waves get interrupted. Consequently, the short, choppy wave of a high-frequency chirp is likely to bounce away before reaching your ears. This is why animals that communicate over long distances—such as social animals like wolves and elephants, or solitary animals like koalas and humpback whales—use low-frequency calls that maintain their energy and can travel farther.
For instance, elephants’ rumbles, which are so low-frequency that humans can’t hear them, can reach herd mates up to 10 kilometers away. Sounds travel even farther in water than in air, so some whales’ low-frequency songs can travel over a thousand kilometers. While animals can use medium and high-frequency calls, these calls fade out more quickly, requiring the animals to be closer together.
High-frequency calls are particularly effective when animals want their calls to bounce off objects. Bats and dolphins use high-frequency vocalizations because these calls reflect off small obstacles like insects or fish.
Ultimately, communication—whether high- or low-frequency—is about ensuring that your call reaches the right ears.
Now that you know a bit about sound wave characteristics, how would you go about stopping them? For that, you should check out Brilliant, the sponsor of this video. Brilliant can help guide you to mastery by breaking down complex science or math concepts—like how waves travel and interact—into understandable chunks. You can learn about standing waves, the Doppler effect, and how noise-canceling headphones work.
When you challenge yourself a little each day, you’ll be amazed at what you can accomplish. Visit brilliant.org/MinuteEarth to sign up for free. As a bonus for MinuteEarth viewers, the first 200 people to go to that link will receive 20% off an annual Premium subscription. Click on the link in the description and try Brilliant now.
Sound – Vibrations that travel through the air or another medium and can be heard when they reach a person’s or animal’s ear. – Example sentence: Sound travels faster in water than in air because the particles in water are closer together.
Waves – Disturbances that transfer energy from one place to another without transferring matter. – Example sentence: Ocean waves are a visible example of how energy can move through water.
Frequency – The number of waves that pass a fixed point in a given amount of time, usually measured in hertz (Hz). – Example sentence: The frequency of a sound wave determines its pitch, with higher frequencies producing higher-pitched sounds.
Travel – The movement of waves through a medium from one location to another. – Example sentence: Light waves travel faster than sound waves, which is why we see lightning before we hear thunder.
Energy – The ability to do work or cause change, which can be transferred through waves. – Example sentence: The energy from the sun travels to Earth in the form of electromagnetic waves.
Communicate – To share or exchange information, often using sound waves or other signals. – Example sentence: Dolphins communicate with each other using a series of clicks and whistles.
Animals – Living organisms that can move and respond to their environment, often using sound for communication. – Example sentence: Many animals use sound to communicate, such as birds singing to attract mates.
High – Having a large amount of energy or frequency, often used to describe sound waves with a high pitch. – Example sentence: The high-pitched sound of a whistle can be heard over long distances.
Low – Having a small amount of energy or frequency, often used to describe sound waves with a low pitch. – Example sentence: The low rumble of thunder can be felt as well as heard.
Echolocation – A method used by some animals to locate objects by emitting sound waves and listening for the echoes that return. – Example sentence: Bats use echolocation to navigate and find food in the dark.
