Making Waves with Sound and Light
Summary
TLDRThis video explores the differences between light and sound waves, highlighting their distinct behaviors. Light, an electromagnetic wave, doesn't need a medium to travel, unlike sound, a mechanical wave requiring solids, liquids, or gases. Demonstrations using a vacuum chamber show light can travel through a vacuum but sound cannot. The video also explains the delay between seeing lightning and hearing thunder due to the vastly different speeds of light and sound, allowing viewers to estimate distances to storms using the delay.
Takeaways
- 🌌 Light and sound are both waves, but they behave differently as light is an electromagnetic wave and sound is a mechanical wave.
- 🌐 Sound requires a medium like solid, liquid, or gas to travel, whereas light does not need a medium for propagation.
- 📱 A demonstration with a cell phone in a vacuum chamber shows that light can be seen without a medium, but sound cannot be heard.
- ⏱️ There's a significant delay between seeing and hearing due to the different speeds of light and sound, with light being much faster.
- ⚡️ The delay between seeing lightning and hearing thunder is a practical example of the difference in speed between light and sound.
- 📏 The speed of light is approximately 186,000 miles per second, while the speed of sound is about 0.2 miles per second.
- 🔍 By observing the delay between an event's light and sound, one can estimate distances, such as the distance to a storm.
- 📐 A general rule of thumb is that a 5-second delay in hearing thunder after seeing lightning corresponds to about 1 mile distance.
- 🎥 The video example illustrates how to calculate the distance to an event by using the delay between seeing an explosion and hearing the sound.
- 🧮 The calculation method involves multiplying the delay in seconds by the speed of sound to find the distance in miles.
Q & A
What are the two types of waves discussed in the script?
-The script discusses two types of waves: light, which is an electromagnetic wave, and sound, which is a mechanical wave.
Why does sound require a medium to propagate?
-Sound is a mechanical wave and needs a medium like a solid, liquid, or gas to travel through because it involves the vibration of particles in that medium.
How does the propagation of light differ from sound?
-Light is an electromagnetic wave and does not require a medium to propagate; it can travel through a vacuum.
What happens to sound when air is removed from a vacuum chamber?
-When air is removed from a vacuum chamber, sound cannot travel because there is no medium for the sound waves to propagate through.
Why can we still see light when the phone is in a vacuum chamber?
-We can see light from the phone screen in a vacuum chamber because light is an electromagnetic wave and does not require a medium to travel; it can propagate through a vacuum.
What is the speed of light in miles per second?
-The speed of light is approximately 186,000 miles per second.
What is the speed of sound in miles per second?
-The speed of sound is about 0.2 miles per second.
Why do we see lightning before we hear thunder?
-We see lightning before we hear thunder because light travels much faster than sound, causing a delay between the visual and auditory perception of a storm.
How can the delay between seeing lightning and hearing thunder be used to estimate the distance to a storm?
-The delay between seeing lightning and hearing thunder can be used to estimate the distance to a storm by multiplying the delay in seconds by the speed of sound (0.2 miles per second).
What is the general rule for estimating the distance to a storm based on the delay between lightning and thunder?
-As a general rule, every 5 seconds delay in hearing thunder after seeing lightning corresponds to approximately 1 mile distance from the storm.
How can the viewer estimate the distance to an explosion using the information provided in the script?
-The viewer can estimate the distance to an explosion by multiplying the delay in seconds between seeing the light and hearing the sound by the speed of sound (0.2 miles per second).
Outlines
🌌 Understanding Light and Sound Waves
This paragraph introduces the fundamental differences between light and sound waves. Light is an electromagnetic wave that can travel through a vacuum, whereas sound is a mechanical wave requiring a medium like solids, liquids, or gases to propagate. The speaker, Dan, an MIT undergraduate, uses a vacuum chamber to demonstrate how sound cannot travel in a vacuum, unlike light. This experiment visually and audibly illustrates the dependency of sound on a medium, while light continues to be visible even in the absence of air or other gases.
Mindmap
Keywords
💡Light
💡Sound
💡Mechanical Wave
💡Electromagnetic Wave
💡Propagation
💡Vacuum Chamber
💡Speed of Light
💡Speed of Sound
💡Delay
💡Distance Estimation
💡Man Vehicle Lab
Highlights
Light and sound are both waves that travel through time and space, but they have different behaviors and properties.
Sound is a mechanical wave that requires a medium like solid, liquid, or gas to propagate.
Light is an electromagnetic wave that does not require a medium for propagation.
A vacuum chamber experiment demonstrates that sound cannot travel in a vacuum, unlike light.
The speed of light is 186,000 miles per second, much faster than the speed of sound at 0.2 miles per second.
The delay between seeing lightning and hearing thunder is due to the difference in the speed of light and sound.
The further you are from a storm, the larger the delay between seeing lightning and hearing thunder.
The speed of light is so high that its transmission can be considered instantaneous.
Using the delay between the explosion of light and noise, one can estimate the distance to the event.
A general rule is that every 5 seconds delay corresponds to a distance of 1 mile.
The video demonstrates how to calculate the distance to a lightning strike using the delay between lightning and thunder.
The viewer was 0.6 miles from the lightning strike based on the 3-second delay.
A practical example is given to calculate the distance to a storm by counting the delay between lightning and thunder.
The experiment with the phone in a vacuum chamber shows that light can be seen but not the sound when air is removed.
The experiment illustrates the fundamental difference between how light and sound waves behave in the absence of a medium.
The video provides a clear demonstration of the practical applications of understanding the speed of light and sound.
A step-by-step guide is given on how to estimate the distance to a storm using the 5-second rule for sound delay.
Transcripts
we talk we listen we see we use sound
and light every day
all the time but do we really know their
behavior what causes it the delay
between seeing and hearing the firework
hi I'm Dan an MIT undergraduate from the
man vehicle lab and I'm here to talk to
you about the differences between light
and sound light and sound are both waves
that travel through time and space
accompanied by the transference of
energy from one point to another but
this is where the similarities end
sound is a mechanical wave that requires
a medium to propagate through such as a
solid liquid or gas whereas light is an
electromagnetic wave that doesn't
require a propagation medium let's go
see the effects of these different
behaviors you probably use your phone
every day and as you can see when
someone's calling me I can see the light
on the screen and the sound of the
ringtone
now we're going to use the vacuum
chamber we're going to put the cell
phone inside the vacuum chamber and then
turn it on when I turn it on a vacuum
pump will remove the air or other gases
from inside the chamber leaving a
low-pressure environment this
environment will be completely void of
matter just like space look I'm
receiving a phone call again and I can
see the light but what about the sound
of the ringtone and now with no vacuum
we can hear the ringtone again Oh gross
it's my mom we've got to put that back
in the vacuum chamber surely you're
familiar with storms and how we see the
Lightning first and then we hear the
Thunder this is because the speed of
light is 186,000 282 miles per second
whereas the speed of sound is only 0.2
miles per second because of this huge
difference there's a delay between
seeing the light and hearing the sound
and the further you are from the storm
the larger this delay is but this
doesn't only apply to other storms it
also applies to other everyday
situations remember that video from
earlier let's go look at it again as you
noticed we can see the explosion of
light in the sky and just some seconds
later you can hear the sound the delay
was about three seconds and with
information we can estimate the distance
between the viewer and the burst the
speed of light is so high with
transmission of light and be considered
instantaneous so multiplying the speed
of sound by the delay between the
explosion of light and noise we get the
distance in this case the viewer was 0.6
miles from the murder ship and as a
general rule we can assume that every 5
seconds delay corresponds to a distance
of 1 mile now you can know how far away
storm is by doing a few simple
calculations now try it on your own with
the following storm video determine the
distance using the delay between the
lightning and thunder
you
you should have counted about 17 seconds
multiplying this by the speed of sound
of 0.2 miles per second you should get a
distance of 3.4 miles
you
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