Sound | Grade 8 Science DepEd MELC Quarter 1 Module 4 Part 2

Summary

This video explores the nature of sound, explaining that it's a mechanical wave produced by vibrations requiring a medium to travel. It compares sound propagation in solids, liquids, and gases, noting that sound travels fastest in solids due to stronger molecular bonds. The video also addresses how temperature affects sound speed, demonstrating with an equation that sound travels faster in warmer temperatures. A practical activity is included to illustrate these concepts, and the video concludes with a teaser for the next part of the series on light.

Takeaways

• 🎵 Sound is produced by vibrations, such as plucking a guitar string or wind blowing through leaves.
• 🌊 Sound is a mechanical wave that requires a medium (solid, liquid, or gas) to travel through.
• 🌌 We cannot hear stars because space is nearly a vacuum, which is not a suitable medium for sound to travel.
• 👂 An activity demonstrates that sound travels better through solids, as heard when the ear is in contact with a solid surface.
• 🔊 The speed of sound varies in different media, being fastest in solids, followed by liquids, and slowest in gases.
• 🌡️ Temperature affects the speed of sound, with warmer temperatures causing sound to travel faster due to increased particle kinetic energy.
• ⏱️ The speed of sound in dry air at 0 degrees Celsius is approximately 331 meters per second.
• ☀️ During summer, the speed of sound is greater than in colder months because of the higher temperature.
• 📐 The formula to calculate the speed of sound is \( v = 331 + 0.6t \), where \( v \) is the speed of sound, and \( t \) is the temperature in degrees Celsius.
• 🚒 An example calculation shows that the speed of sound is 354.4 meters per second at a temperature of 39 degrees Celsius.

Q & A

What is the primary cause of sound production?

Sound is produced by vibrations. For instance, when a guitar string is plucked or wind blows through leaves, the vibrations create sound.

Why do we not hear stars like we see them?

We do not hear stars because sound requires a medium to travel, and space is nearly a vacuum, which does not support the propagation of sound.

What is a mechanical wave?

Sound is a form of mechanical wave, which means it needs a medium to be transported from one location to another.

Why does sound travel differently underwater compared to above water?

Sound travels differently underwater because the medium underwater is liquid, while above water it is gas. The speed and quality of sound are affected by the medium's properties.

How does temperature affect the speed of sound?

Temperature affects the speed of sound because it influences the kinetic energy of particles in the medium. Higher temperatures result in faster particle vibrations and more efficient energy transfer, thus increasing the speed of sound.

What is the speed of sound in dry air at 0 degrees Celsius?

The speed of sound in dry air at 0 degrees Celsius is approximately 331 meters per second.

How does the equation for the speed of sound in relation to temperature look?

The equation for the speed of sound considering temperature is: 'v = 331 + 0.6 × temperature in degrees Celsius'.

Why do cars and trucks sound louder in summer than in colder months?

The sound of cars and trucks is louder in summer because the increased temperature of the air causes sound to travel faster and more efficiently.

What happens during the activity where one person taps a table while another has their ear against it?

During the activity, the person hears a louder and more pronounced sound when their ear is against the table because sound waves travel effectively through the solid material of the table.

How do the bond strengths between molecules in solids, liquids, and gases affect the speed of sound?

Sound waves travel faster in solids than in liquids and faster in liquids than in gases due to the bond strength between molecules being strongest in solids and weakest in gases.

What is the speed of sound during summer at a temperature of 39 degrees Celsius?

Using the formula 'v = 331 + 0.6 × temperature in degrees Celsius', the speed of sound at 39 degrees Celsius is approximately 354.4 meters per second.

Outlines

00:00

🎵 Understanding Sound Waves

This paragraph introduces the concept of sound, explaining that it is produced by vibrations. Examples include plucking a guitar string or wind blowing through leaves. Sound is a mechanical wave that requires a medium to travel, such as solids, liquids, or gases. The paragraph also discusses why we cannot hear stars, as sound cannot travel through the vacuum of space. An activity is suggested to demonstrate how sound travels through solids, with the experience of sound being louder when the ear is in contact with the solid surface. The paragraph concludes by explaining that sound waves travel faster in solids than in liquids and gases due to the molecular bond strength and arrangement.

05:02

🔍 The Impact of Temperature on Sound Speed

This paragraph delves into the effect of temperature on the speed of sound. It explains that sound, being a form of kinetic energy, travels faster in media with higher temperatures because particles vibrate more rapidly, leading to more efficient energy transfer. The speed of sound in dry air at 0 degrees Celsius is given as 331 meters per second, with an increase of 0.6 meters per second for every degree Celsius above zero. A formula is provided to calculate the speed of sound based on temperature, and an example calculation is done for a summer temperature of 39 degrees Celsius, resulting in a speed of 354.4 meters per second. The paragraph emphasizes the importance of understanding how the medium and temperature affect sound propagation.

Keywords

💡Sound

Sound is a mechanical wave that is produced by vibrations. In the video, it is explained that all sounds are generated by vibrations, such as when a guitar string is plucked or leaves rustle in the wind. The concept is central to understanding how we perceive different sounds and how they travel through various mediums. The video uses the example of sound traveling differently underwater compared to above water to illustrate the role of the medium in sound propagation.

💡Vibrations

Vibrations refer to the oscillatory motion of an object or particle around an equilibrium point. The video script explains that vibrations are the source of sound, as they create sound waves. For instance, when a guitar string is plucked, it vibrates and produces sound, demonstrating how vibrations are directly linked to the production of audible frequencies.

💡Medium

A medium is any substance through which energy, including sound, can be transmitted. The video emphasizes that sound requires a medium to travel, such as solids, liquids, or gases. It contrasts this with the vacuum of space, where sound cannot travel because there is no medium to carry the vibrations. The concept is crucial for understanding the conditions under which sound can propagate.

💡Mechanical Wave

A mechanical wave is a disturbance that propagates through a medium by the movement of particles of the medium. Sound is described as a form of mechanical wave in the video, which means it requires a material medium to travel. The video script uses the example of placing an ear against a table to demonstrate how sound waves travel through a solid medium more effectively.

💡Vacuum

A vacuum is a space devoid of matter, where air pressure is much lower than in the atmosphere. The video explains that sound cannot travel through a vacuum because there are no particles to transmit the vibrations. This is used to contrast with the ability of sound to travel through mediums like solids, liquids, and gases.

💡Temperature

Temperature is a measure of the average kinetic energy of the particles in a substance. The video script discusses how temperature affects the speed of sound, with sound traveling faster in warmer temperatures. This is because the particles in a medium vibrate faster at higher temperatures, leading to more efficient energy transfer and faster sound propagation.

💡Kinetic Energy

Kinetic energy is the energy possessed by an object due to its motion. The video relates sound to kinetic energy, explaining that sound is a form of energy that is transferred through vibrations. It also mentions that the speed of sound is affected by the kinetic energy of particles in the medium, with higher kinetic energy leading to faster sound propagation.

💡Molecular Arrangement

Molecular arrangement refers to the way molecules are positioned in relation to each other within a substance. The video script mentions that the bond strength between molecules affects how sound waves travel through different states of matter, with solids generally allowing sound to travel faster due to stronger intermolecular bonds.

💡Speed of Sound

The speed of sound is the rate at which a sound wave propagates through a medium. The video provides a formula to calculate the speed of sound in relation to temperature, demonstrating that it varies with the medium's temperature. It uses the example of a fire truck's siren to calculate the speed of sound at 39 degrees Celsius, showing how the concept is applied practically.

💡Liquid

Liquid is one of the states of matter, characterized by its ability to flow and take the shape of its container. The video contrasts the properties of liquids with gases when discussing how sound travels through them. It notes that sound travels differently underwater (liquid) compared to air (gas), which is crucial for understanding the perception of sound in different environments.

💡Gas

Gas is a state of matter that can expand to fill its container and is less dense than solids and liquids. The video script explains that the speed of sound is slower in gases compared to solids and liquids due to weaker intermolecular forces. This is exemplified by the difference in sound perception when comparing underwater (liquid) and above water (gas) environments.

Highlights

Sounds are different underwater due to the medium being liquid compared to gas above the water surface.

Sound of cars and trucks is louder in summer because temperature affects the speed of sound.

All sounds are produced by vibrations, requiring a medium to travel.

Sound is a form of mechanical wave that needs a medium like solid, liquid, or gas to propagate.

Stars are silent because space is nearly a vacuum, lacking a medium for sound to travel.

An activity is suggested to demonstrate how sound travels through a solid medium like a table.

Sound waves travel faster in solids than in liquids, and faster in liquids than in gases.

The molecular arrangement and bond strength between molecules affect how fast sound waves travel.

Temperature influences the speed of sound, with higher temperatures leading to faster sound propagation.

Sound travels at approximately 331 meters per second in dry air at 0 degrees Celsius.

The speed of sound increases with the temperature of the medium.

A formula is provided to calculate the speed of sound based on temperature.

An example calculation shows the speed of sound at 39 degrees Celsius.

The speed of sound is a sum of a base speed and an increment based on temperature in degrees Celsius.

The video concludes with a teaser for part 3 of the series about light.

The video encourages viewers to subscribe and stay engaged for more educational content.

Transcripts

[Music]

have you ever wondered why sounds are

different underwater

compared to when you are above the

surface of the water

why do you think the sound of cars and

trucks is louder during summer

than it is during the colder months

in this video we will be discussing the

concept of sound

so what is sound

all sounds are produced by vibrations

when you pluck a guitar string

it vibrates and produces a sound when

the wind blows through a tree

the leaves vibrate and produce a

rustling sound

when sound waves reach your ears the

waves cause your eardrums to vibrate

sound is a form of mechanical wave this

means that

sound requires a medium so that it can

be transported

from one location to another a medium is

anything that allows the transfer of

energy

in our topic these include solid

liquid and gas

this is the reason why we can see the

bright stars at night

but have never heard how they sound like

as mentioned

sound needs medium to travel and since

space is close to vacuum

which is an empty space sound is hardly

heard

sound cannot travel through vacuum

alright so let's do this activity

place your ear against one end of a

table top

ask a friend to gently tap the other end

of the table

with a pencil or a ruler observe

what happens then ask your friend to

gently tap the other end of the table

but this time make sure that your ear is

not touching the table

observe and compare what you heard from

the first position

in which situation did you encounter

louder and more pronounced sound

sound travels as a wave of mechanical

vibrations

through a medium in this activity you

heard a louder sound

when the table was tapped while your ear

is against its surface

than when your ear was not touching the

table

this shows that sound waves can travel

through wood

or solid and even in air try to recall

the molecular arrangement of the

molecules of

solid liquid and gas

generally the bond strength between

molecules is strongest in solid

materials

and is weakest in gases thus

sound waves travel faster in solids than

in liquids

and faster in liquids than in gases

this is the reason why sounds underwater

are different compared to

above the surface since the medium

underwater is liquid

and the medium above the surface of the

water is gas

remember when i mentioned that the sound

of cars and trucks is louder during

summer

than it is during colder months that's

because

temperature also affects the speed of

sound

sound just like heat is a form of

kinetic energy

the speed of sound is directly affected

by the temperature of the medium

at higher temperatures particles have

more kinetic energy

and thus particles vibrate faster

and when particles vibrate faster there

will be more collisions per unit time

with more collisions per unit time

energy is transferred more efficiently

resulting in sound traveling faster

sound travels at about 331 meters per

second in dry air

at 0 degrees celsius the speed of sound

is dependent on temperature of the

medium

where an increase is observed with an

increase in temperature

this means that at temperatures greater

than zero degrees celsius

speed of sound is greater than 331

meters per second

by an amount of 0.6 meters per second

over degrees celsius multiplied by the

temperature of the medium

in equation form speed of sound is equal

to

331 meters per second

plus 0.6 meters per second

over degrees celsius times temperature

thus in equation speed of sound is equal

to

331 meters per second plus

0.6 meters per second in every degree

celsius times temperature where

v is the speed of sound t

is the temperature 331 meters per second

and 0.6 meters per second are constant

factors

let's try calculating for the speed of

sound

what is the speed of sound from a fire

truck passing by the street in front of

your house during summer

with the temperature of 39 degrees

celsius

so we have the formula speed of sound

is equal to 331 meters per second

plus 0.6 meters per second

in every degree celsius times

temperature

the given temperature is 39 degrees

celsius

we can cancel out similar units such as

the degree celsius

0.6 meters per second times 39

is equal to 23.4 meters per second

331 meters per second plus 23.4 meters

per second

equals 354.4 meters per second

now remember sound is a form of

mechanical wave and is produced by

vibrations

propagation of sound is affected by its

medium while the speed of sound is

affected by the temperature of its

medium

that's all for now stay tuned for part 3

of this series about light

see you on our next video and don't

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