What is Infrasound — Reading Comprehension

Grades

About This Reader

"This NGSS-aligned passage explores the fascinating world of infrasound, a type of sound with frequencies below the range of human hearing. Designed for middle school students, the reading passage explains the basic physics of sound waves, focusing on infrasound's unique characteristics, such as its long wavelengths and ability to travel great distances. It provides concrete examples of how animals like elephants and whales use infrasound for long-distance communication. The passage also delves into the practical applications of infrasound in modern science, including its use in monitoring geological and atmospheric events like volcanic eruptions, hurricanes, and nuclear tests. Key vocabulary terms are bolded to enhance learning. This resource supports the understanding of wave properties and their applications as outlined in the NGSS standards, specifically MS-PS4-1, which focuses on developing a model to describe that waves are reflected, absorbed, or transmitted through various materials."

CONTENT PREVIEW

Sound is created by vibrations that travel through a medium like air or water as waves. The frequency of these waves, measured in hertz (Hz), determines the sound's pitch. Humans can hear sounds within a specific range, typically from 20 Hz to 20,000 Hz. Sounds with frequencies below this range, less than 20 Hz, are known as infrasound. These low-frequency sound waves are too low-pitched for the human ear to detect, making them "unheard" by us. Although we cannot hear infrasound, it is a powerful force that constantly surrounds us, carrying energy over vast distances.

One of the most fascinating aspects of infrasound is its ability to travel great distances with very little loss of energy. This is due to its long wavelengths, which allow the sound waves to bend around large obstacles without being blocked. Many animals, particularly large ones like elephants and whales, use infrasound to communicate. Elephants can produce low-frequency rumbles that travel through the ground for miles, allowing them to coordinate herd movements or find mates across large territories. Similarly, whales use infrasound to communicate with other whales over hundreds of miles in the ocean.

Scientists utilize specialized equipment to detect and study infrasound from both natural and human-made sources. For example, the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) has a global network of infrasound sensors to monitor for nuclear explosions, which produce distinct infrasonic signatures. This same technology is used in seismology and meteorology to detect natural events. Scientists can use infrasound to monitor volcanic eruptions, track severe weather like tornadoes and hurricanes, and even detect meteors as they enter the atmosphere. These applications demonstrate how infrasound provides a hidden layer of information about our planet and atmosphere.

Fun Fact: A tiger's roar contains infrasound frequencies so low that it can temporarily paralyze its prey, making them unable to move for a few seconds.

What is the frequency range of sound that humans can typically hear?

Below 20 HzBetween 20 Hz and 20,000 HzAbove 20,000 HzAll of the above

What is infrasound?

Sound with high-pitched frequenciesSound that travels only in waterSound with frequencies below 20 HzSound that is absorbed by objects

What characteristic allows infrasound to travel long distances?

Its high pitchIts short wavelengthsIts low energyIts long wavelengths

According to the passage, which animals use infrasound for communication?

Bats and dogsElephants and whalesBirds and fishLizards and snakes

How do scientists use infrasound technology?

To create music for animalsTo make sounds louder for humansTo monitor natural and man-made eventsTo block communication signals

Why is it useful for scientists to monitor infrasound from volcanic eruptions?

To predict when an eruption will occurTo determine the size of the eruptionTo confirm that a volcano has eruptedAll of the above

Based on the passage, what is the main idea?

Infrasound is the only type of sound used by animals.The human ear is not sensitive enough to hear infrasound.Infrasound is a type of sound that is vital for science and nature.Scientists can create infrasound to control the weather.

A scientist places an infrasound sensor on a remote island. If the sensor detects a strong infrasound signal, what is a likely cause based on the passage?

A nearby car hornA small bird singingA distant hurricaneA radio broadcast