BoatSafe Kids! How does the moon affect tides?
Specifically, the gravitational forces of the Sun and Moon. The key to understanding how the tides work is understanding the relationship between the motion of. The moon and the sun combine to create tides in Earth's oceans (in fact They occur because of the difference in gravitational effect on one. A tidal force is related to gravity, but it isn't the same thing. It's really the difference between the the strength of gravity at two locations.
Tide does not ebb, nor does it come in or go out.
Tide is defined as the vertical movement of water and only goes up and down. Current is the horizontal or sideways flow of water.
The Ocean's Tides Explained
It floods in which makes the tide rise and ebbs out which makes the tide fall. It is this up and down tidal movement that you should be concerned with and be able to estimate with some accuracy, especially when entering a potentially shallow port or harbor.
First of all, tide is the rise and fall of water caused by gravitational forces of the moon and sun on the oceans of the earth. Generally speaking, tidal cycles contain two high tides and two low tides each day. During the time between high and low tide there will obviously be current flow. The time between high and low tides is a little over 6 hours and the entire tidal cycle repeats itself approximately fifty minutes later each day.
So if you know that low tide is at today you can estimate that it will be at tomorrow.
The difference between the high tide and low tide is called the range of tide. For instance, if the water depth at high tide is 20 feet and at low tide is 18 feet, the range of tide is two feet. There are two types of currents that you can expect in regard to tides.How the Moon Affects the Ocean Tides - Tides and the Moon - CharlieDeanArchives / Archival Footage
Flooding current is experienced when the tide is rising. Ebbing current is experienced when the tide is falling.
The Ocean's Tides Explained
When the tide has reached it highest and lowest points there is a brief period where there is no current ebbing or flooding, this is referred to as slack water. High and low tides both appear two times each in a hour day, but since the moon rises 50 minutes later each day, the tide cycles will differ by the same 50 minutes daily.
Spring Tides The phases of the moon also affect tides. When the moon is at its full or new moon phase, high tides are at their highest, while low tides are lower than usual. Called spring tides, these tides occur when the sun, moon and the Earth all line up. The added gravity of the sun can make the oceans bulge more than at other times. Neap Tides During the moon's quarter phases, the sun pulls against the moon's gravitational pull instead of with it.
During these tides, the result is the lowest high tide and the highest low tide -- in other words, the least extreme difference between high and low tides. This is called a neap tide. Too Close for Comfort If the moon is at perigee, or the closest point in its orbit around the Earth, the tides can also be affected.
Combined with a full or new phase, a moon at perigee can produce the highest and lowest tides of all. Scientists can easily predict these highest of tides so that warnings can be issued for possible coastal flooding.