Snorkelling Science Review

This set of flashcards covers the physical properties of underwater environments including light refraction, sound conduction, heat loss, resistance, and atmospheric pressure (ATM/ATA) as they relate to snorkelling science.

What is light made of according to the notes?

Light is electromagnetic energy made up of different wavelengths.

Which light wavelengths are absorbed first in shallower water?

Longwave wavelength colours such as red, orange, and yellow.

Which light wavelengths are scattered at varying depths?

Shortwave wavelength colours such as green, blue, indigo, and violet.

How does refraction affect the appearance of objects underwater?

Objects appear approximately $25\%$ larger and closer.

What can be used to overcome the problem of light being absorbed underwater?

Artificial lighting, also known as a dive torch.

How much faster does sound travel in water compared to air and why?

Sound travels around $4$ times faster because water is denser than air, providing more particles for soundwaves to vibrate off.

What is the sensory result of sound traveling faster underwater?

It results in greater difficulty determining the direction of the sound.

How much faster does water conduct heat from the body compared to air?

Over $25$ times faster.

What condition can prolonged exposure to cold water lead to?

Hypothermia.

Do wetsuits prevent heat loss underwater?

No, wetsuits can delay heat loss, but they do not prevent it.

What creates greater resistance for a person moving through water compared to air?

Water's density.

How can a snorkeller overcome resistance and prevent overexertion?

By streamlining their body position and wearing fins to propel through the water.

What is the pressure at the surface of the water equivalent to in $kg\,cm^{-2}$?

$1.03\,kg\,cm^{-2}$ ($1\,ATM$).

For every $10\,m$ of depth, how much does the pressure increase?

The pressure increases by the equivalent of $1\,ATM$ for every $10\,m$.

What does the term ATA (Atmosphere Absolute) refer to?

The total atmospheric pressure on a diver, which is the pressure of the depth plus the pressure on the surface.

What is the Atmosphere Absolute ($ATA$) at a depth of $20\,m$?

$3\,ATA$ ($1\,ATA$ from surface + $2\,ATA$ from depth).

What is the total pressure in $ATM$ at a depth of $14\,m$?

$2.4\,ATM$.

What is the pressure at the Titanic depth of $3,800\,m$?

$380\,ATM$.

What is the $ATA$ value at a depth of $33\,m$?

$4.3\,ATA$.