What happens to the amount of light as you go deeper in an aquatic system?

Answer 1

• If you can hear thunder, the lightning strike has already occurred since thunder is only a sonic boom caused by lightning. In order for you to feel an electric shock an electric current must pass through your body. For a current to pass through your body, your body must complete the circuit from an electrostatically charged cloud to earth/ground (in this example the ocean is the electrical earth/ground). Salt water is a great conductor of electricity/lightning and thus would immediately discharge the lightning strike. Unless the strike actually hits you, you are not in the circuit and would therefore feel nothing from a strike into the ocean - no matter how close. Consider the case of a bird perched on a high voltage supply line (maybe 440,000 volts). The bird is charged with 440,000 volts of electricity alright, but there is no circuit to ground/earth/ocean, thus the bird is not electrocuted and feels nothing.

• The sea is not like your bath tub, as the sea is much much larger than even a very big bath tub. After all, there is lightning hitting some part of the oceans some place, some where, every minute of every day, isn't there? If it were just like dropping a radio into a bath tub, then people playing in the ocean at Virginia Beach would be shocked to death whenever lightning struck the water off the coast of South Africa. But we know that doesn't happen. Water has resistance. Salt water has a lower resistance than drinking water, but it does have some resistance. That resistance is cumulative per unit of volume of water. As the distance grows from the strike point to the observer, the amount of energy observable is less.

• Resistance is not the major determination whether the one feels it, it is dependant on the voltage and current in that strike (changed by how far electricity has to travel, humidity, size of clouds, etc.). To see why, look at how lightning works: friction, among other things, releases negative electrons in the sky. In a storm this charge of electrons that have no place to go become attracted to the positive charged earth and take that leap. They hit the water and spread. Everything that has room takes an electron (ionizes) and the charge dissipates. My speculation is that after 100 feet or so you probably wouldn't feel it too much. Is someone going to jump in the water during a storm? It isn't recommended.

• Salt water is a much better conductor than fresh. Salt water contains positive and negative ions (Na+ and Cl-), which lower its resistance. Fresh water, which contains fewer ions to transport charge, will have a higher resistance. Thinking about it a little longer: V=IR, where V = voltage, I = current, and R = resistance. In the case of a lightning bolt, I would imagine you could consider it a two resistor system, the water between you and the strike being the first resistor, and you being the second. Voltage will be supplied by the lightning bolt. The voltage will drop after traveling through the water. If there is enough voltage to provide a large enough current through yourself then you will feel it.

• What a person will feel (1ma), will kill them (10ma) is not directly based on distance from the strike, it is based on the voltage gradient (across the person), which is determined by the distance from the strike and the other paths that the charge can take to Earth. So, it is not linear or easily calculated because of the many different variables.

• First, pure water is an insulator. Salt and impurities make it conduct. Second, you cannot separate voltage, current and resistance. They are related to each other. The voltage of the lightning strike, along with the resistance of the water determines the current allowed to flow. Current is limited by resistance. Current can be increased by increasing voltage or decreasing resistance. Therefore, the distance from the strike will increase resistance and therefore decrease current; voltage will drop as well (as in a voltage divider circuit). There are several laws that I can think of, (multiples of resistance, etc) that would probably help answer the question, but it's just not that simple. It's not even known why lightning "chooses" the path it takes in the first place. Bottom line, if you can see lightning, get out of the water.

Read more: If_lightning_strikes_the_ocean_while_you_are_in_it_how_close_does_the_strike_have_to_be_for_you_to_feel_it

Answer 2

Light changes when you get deeper into the ocean because the water absorbs the light. Red in particular gets absorbed the fastest, in the first couple feet. For example, if you wear red footwear into the ocean, they would look gray instead of red. That is why light changes in the depth of the ocean.