Question

Explain Suppose two astronauts are outside the space shuttle orbiting Earth. The audio speaker in the helmet of one astronaut quits working. The other astronaut is \(1 \mathrm{~m}\) away and shouts a message. Can the first astronaut hear the message? Support your reasoning.

Short answer

No, the first astronaut cannot hear the message because space is a vacuum and does not transmit sound.

Step-by-step solution

Understanding Sound Transmission

Sound is a mechanical wave that requires a medium, like air or water, to travel. In outer space, there is no air or any other common medium that can transmit sound waves.

Conditions in Space

Space is a vacuum, which means it is an environment devoid of air molecules. Because of this lack of a medium, sound waves cannot propagate through space as they would on Earth.

Evaluating the Situation

Given that the astronauts are outside the space shuttle, they are effectively in a vacuum where sound cannot travel. Therefore, the sound from the shouting astronaut cannot reach the other astronaut because there's no medium to carry the sound waves.

Conclusion

Without a medium to transmit sound, the first astronaut will not be able to hear the shout from the second astronaut, even though they are only 1 meter apart.

Key concepts

Sound Waves

Sound waves are vibrations that travel through a medium like air, water, or solid materials. These waves are mechanical in nature, which means they need a substance to carry the sound. The waves move by compressing and decompressing the medium. This compression-decompression cycle continues until the sound reaches your ears, where it is interpreted by the brain.

• Sound travels at different speeds in different mediums.
• In air, it travels at approximately 343 meters per second.
• In water, it's faster, around 1482 meters per second.
• Sound can't travel through a vacuum as there are no particles to transmit the vibrations.

Vacuum

A vacuum is a space entirely devoid of matter, which means there are no air particles in it. In everyday terms, you can think of a vacuum as a complete absence of air. It's akin to sucking all the air out of a bottle; nothing is left to carry sound.
In space, the vacuum is large-scale, being the natural environment outside planets and in between stars. This absence of air is why space appears to be silent. Here’s why a vacuum matters:

• Sound needs particles to move through, and a vacuum has none.
• Light and radio waves, which don't need a medium, can propagate through a vacuum.

Thus, while space is full of wonders, it’s eerily silent because there’s no medium for sound to travel.

Medium for Sound

A medium for sound is any substance matter composed of molecules. Sound is transferred by the vibration of molecule particles in a chain reaction. When you speak, for instance, your vocal cords create vibrations in the air, which is the medium for sound. This is why you can hear conversations, music, and almost any noise in our atmosphere.

• Common mediums include air, water, and solids like metal.
• The denser the medium, the faster sound can travel.
• Air is the most usual medium we experience, but sound travels even better in liquids and solids.

If there's no medium, like in vacuum space, sound waves cannot travel to convey messages.

Communication in Space

Communication in space poses unique challenges as traditional sound waves cannot be used due to the vacuum. Astronauts use other methods for communication.
For instance, astronauts depending solely on sound to communicate would find it impossible to do so without a medium. Instead, they rely on:

• Radio Waves: These electromagnetic waves do not need a medium and can travel through the vacuum of space.
• Electronic Devices: Devices convert sounds into signals that are transmitted via radio waves to the receiver, where they are converted back to sound.
• Visual Signals: Hand signals or written messages on boards inside spacecrafts for back-up communication.

These methods ensure that communication remains crystal clear even in space's challenging environment.