Sound travels very well through water, about 4 times faster through water than air. Think about how well whales can 'talk' to each other over miles and miles apart. Sound just needs 'something' to travel through. Even warm air is better than cold air for sound wavces to travel through. Check out this page for all sorts of interesting info on sound travel. http://www.dosits.org/science/ssea/3.htm

Sound in water and sound in air are both waves that move similarly and can be characterized the same way. Sound waves can travel through any substance, including gases (such as air), liquids (such as water), and solids (such as the seafloor). Did you know that sound cannot exist if it doesn't have something to travel through? For example, sound cannot travel through outer space because it is a vacuum that contains nothing to carry sound. Even though sound waves in water and sound waves in air are basically similar, the way that sound levels in water and sound levels in air are reported is very different, and comparing sound levels in water and air must be done carefully. When we describe a sound as loud or soft, scientists say that the sound has a high or low amplitude or intensity. Amplitude refers to the change in pressure as the sound wave passes by. If you increase the amplitude of a sound, you are making it louder, just as you do when you turn up the volume on your radio. If you decrease the amplitude, you are making the sound softer, just as when you turn down the volume. The amplitude of a wave is related to the amount of energy it carries. A high amplitude wave carries a large amount of energy; a low amplitude wave carries a small amount of energy. The average amount of energy passing through a unit area per unit time in a specified direction is called the intensity of the wave. As the amplitude of the sound wave increases, the intensity of the sound increases. Sounds with higher intensities are perceived to be louder. The amount of energy per unit time is called power. The intensity of a sound wave is therefore the amount of power transmitted through a specified area in the direction in which the sound is traveling. Power is measured in watts, and intensity is therefore measured in watts per square meter. An example of power with which you are probably familiar is light bulbs, which are commonly labeled in terms of the amount of electrical power that they use (60 watts, 100 watts, etc.). Lights waves have intensity just as sound waves do. The amount of power that a light bulb uses is directly related to the intensity of the light waves that it puts out. Sound intensities given in watts per square meter can be directly compared between water and air. However, scientists often specify sound intensity as a ratio, changing the unit from an absolute intensity to a relative intensity. They have given the name "Bel" to the logarithm of the ratio of a sound's intensity to a reference intensity. A decibel is 1/10 of a Bel. For that reason, relative sound intensities are often reported in decibels (written as dB). The decibel is a relative unit of measure, not an absolute one as is watts per square meter. The result is that sound waves with the same intensities in water and air when measured in watts per square meter have relative intensities that differ by 61.5 dB. This amount must be subtracted from relative intensities in water referenced to 1 microPascal (µPa) to obtain the relative intensities of sound waves in air referenced to 20 microPascals (µPa) that have the same absolute intensity in watts per square meter. The difference in reference intensities causes 26 dB of the 61.5 dB difference. The differences in densities and sound speeds account for the other 35.5 dB. A 60-dB difference in relative intensity represents a million-fold difference in power. From: http://www.dosits.org/science/ssea/3.htm Simple answer: Yes, sound does travel through water. And it travels faster.

Yes, faster.

Sound travels through anything that can be compressed, due to the fact that it is a pressure wave. This is how SONAR works. sound will not travel through a vacuum, because there are no molecules to vibrate into compression