# How Long After Per Eardrum Till Water Pool? [Facts!]

Per eardrum means ‘by ear’, and it usually refers to the time it takes for sound to travel through the body and reach the ears. When someone speaks, the sound first reaches the eardrums of the listeners and then spreads through the body as vibrations that can be perceived as sound. Depending on the intensity and quality of the sound, the listening experience can range from subtle to profound. For example, the roar of a jet engine versus the sound of cascading waters or a gentle rumble from a leisurely bike ride.

Water is another important element to consider when determining how long it takes for sound to reach your ears. Vibrations are usually perceived as sound by the human ear if they are above a certain threshold. This means that if you swim in a pool with a waterfall, you can actually hear the water falling down the steep wall even though you are not physically there! The difference is that the water provides a different quality of sound than a regular pool, more like that of a tropical rainforest than a standard swimming pool. This is because of the density of the air surrounding the water as well as the unique composition of water molecules. In most cases, the farther the sound source is from you, the more powerful and clear it will be, making it easier for you to determine its intensity. If you are not sure how long after per eardrum a sound will reach your ears, use this simple formula:

X is the number of meters or yards (1 yard = 0.9 meter) between you and the sound source. Y is the number of meters per second or yards per second (1 meter per second = 1 yard per second). Z is the number of nanoseconds it takes for the sound to reach your ears (1 nanosecond = 1/1,000,000th of a second or 1/1 Millionth of a second). O is the octave (1 octave = 1 whole step; 1 whole step = 2 semitones).

Here are some examples:

• Meters: If you are one meter from the speaker, it will take you about 1 second to feel the rumble.
• Yards: If you are one yard from the speaker, it will take about 1/4 second to feel the rumble.
• Feet: If you are five feet from the speaker, it will take about 1/16th of a second to feel the rumble.
• Inches: If you are two inches from the speaker, it will take about 1/64th of a second to feel the rumble.
• Centimeters: If you are three centimeters from the speaker, it will take about 1/256th of a second to feel the rumble.
• Millimeters: If you are five millimeters from the speaker, it will take about 1/65,536th of a second to feel the rumble.
• Yards, feet, inches, centimeters, and millimeters all abbreviate as you might assume. One yard is abbreviated as ‘1′, one foot as ‘1′, two inches as ‘2′, etc. You will also see people abbreviating time in this manner. ‘20” means it will take about 20”00” or 20 milliseconds (20 times 0”00” = 20) to feel the rumble.
• Sound travels faster in some environments than in others. If you are in a dense room, for example, it may take a little less time for the sound to reach your ears. If you are in a large open space surrounded by water or another liquid, it will take longer for the sound to travel. This is because the water and other liquids provide an environment where sound can travel more easily. This is called the ‘loss’ or ‘absorption’ of sound. The ‘L’ in SAWL (Sound Absorption by Water) stands for ‘loss’ or ‘absorption’.
• You can use this information to help you determine how long it will take for the sound to reach you. For example, if you are in a boat on a lake and you need to know what sound the motor is making, you can use the SAWL equation to determine if your ears are about to be tickled or if you need to plug your ears and run for cover!

Keep in mind that the intensity of the sound, how far it is away from you, and whether you are in a liquid-filled or air-filled space all factor into how long it takes for the sound to reach you. For example, if you are under water and the depth is unknown, you would have to measure the time it takes for the sound to reach your ears to determine how long you have been under water. In this case, the intensity would be considered ‘slight’ and it would take a while for the vibrations to reach you. You might want to try and surface or use a strobe light to reveal the time frame between when you hear the sound and when you see the flash of light. That way you can be certain how long you have been underwater!

If you are not sure how many meters, yards, feet, inches, centimeters, millimeters, or nanoseconds there are in a second, use this handy conversion chart:

• Meters: 1 meter = 0.9 yard = 0.094592 foot = 0.01148 inch = 0.00279 centimeter = 0.00098 millimeter = 0.0004988 nanoseconds
• Yards: 1 yard = 0.9 meter = 0.094592 foot = 0.01148 inch = 0.00279 centimeter = 0.00098 millimeter = 0.0004988 nanoseconds
• Feet: 1 foot = 0.9 meter = 0.094592 yard = 0.01148 inch = 0.00279 centimeter = 0.00098 millimeter = 0.0004988 nanoseconds
• Inches: 1 inch = 1.8 yard = 0.18 foot = 0.0188 centimeter = 0.00098 millimeter = 0.0004988 nanoseconds
• Centimeters: 1 centimeter = 1.8 foot = 0.18 yard = 0.0188 inch = 0.00098 meter = 0.0004988 nanoseconds
• Millimeters: 1 millimeter = 1.8 yard = 0.18 foot = 0.0188 inch = 0.00098 meter = 0.0004988 nanoseconds
• Yards, feet, inches, centimeters, and millimeters all abbreviate as you might assume. One yard is abbreviated as ‘1′, one foot as ‘1′, two inches as ‘2′, etc. You will also see people abbreviating time in this manner. ‘20” means it will take about 20”00” or 20 milliseconds (20 times 0”00” = 20) to feel the rumble.
• Decibels (dB) is a measurement of the power of a sound and is usually given in units of measurement known as ‘decibels above noise level’. One decibel is equal to a tenfold increase in power, which means that if you are standing in a completely quiet area and you hear nothing, it will be equivalent to standing in an area with a 10 dB noise level. This is an extremely general descriptor of sound power and does not take into account the frequency or wavelength of the sound or other factors that can affect the quality and intensity of the sound. For example, a higher-quality recording usually has a louder volume than a lesser-quality recording.