Chris
Staff member
Welcome to the tides web app which has been serving the public since 2004.
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Thank you for visiting. If you have a question about the site or your account and would like to speak with me, click on my name to start a conversation.
An explanation of tides, for your reference.
Tides are primarily caused by the gravitational forces exerted by the Moon and, to a lesser extent, the Sun on Earth's oceans. Here's a step-by-step breakdown of how this works:
1. **Gravitational Pull:**
- **Moon's Influence:** The Moon exerts a gravitational pull on Earth, which is strongest on the side of Earth closest to the Moon. This pull causes water on Earth to bulge towards the Moon, creating a high tide.
- **Sun's Influence:** The Sun also pulls on Earth's water, but since it's much farther away than the Moon, its gravitational effect on tides is about half as strong. However, when the Sun, Moon, and Earth align (during new and full moons), their combined gravitational forces produce higher high tides, known as spring tides.
2. **Centrifugal Force:**
- As Earth rotates, there's also a centrifugal force (an apparent force due to the rotation) that tends to push water away from the center of rotation. This results in another bulge on the opposite side of Earth from the Moon, also contributing to high tide.
3. **Resulting Tides:**
- **High Tides:** There are typically two high tides daily because Earth rotates, bringing any given point on Earth under the Moon's gravitational bulge twice in about 24 hours and 50 minutes (the lunar day).
- **Low Tides:** Between these high tides, water levels drop, leading to low tides. This happens because water is drawn away to form the high tide bulges.
4. **Types of Tides:**
- **Spring Tides:** Occur when the Sun, Moon, and Earth are aligned, increasing the tidal range (the difference between high and low tide).
- **Neap Tides:** Happen when the Sun and Moon are at right angles to each other, reducing the tidal range because the gravitational forces partially cancel each other out.
5. **Local Factors:**
- The shape of the coastline, depth of the ocean, and local geography can greatly influence the timing and height of tides in any given area. For example, in narrow bays or inlets, tidal amplitude can be significantly amplified, leading to very high or low tides.
6. **Tidal Periodicity:**
- Tides have a semi-diurnal nature in most places, meaning two high and two low tides occur each day. However, some regions experience diurnal tides (one high and one low tide per day) or mixed tides where the pattern isn't as regular.
7. **Other Influences:**
- Weather conditions like wind, atmospheric pressure, and even earthquakes or tsunamis can temporarily alter tide levels.
In summary, tides result from the gravitational dance between Earth, the Moon, and the Sun, modulated by Earth's rotation and local geography. This interaction creates the rhythmic rise and fall of sea levels that we observe daily.
When you register you can subscribe for member access. Members experience is without future date restrictions and without ads. Printing calendars for your reference or for your guests is available. The free service includes restrictions on the future content and is displayed with some ads.
Thank you for visiting. If you have a question about the site or your account and would like to speak with me, click on my name to start a conversation.
An explanation of tides, for your reference.
Tides are primarily caused by the gravitational forces exerted by the Moon and, to a lesser extent, the Sun on Earth's oceans. Here's a step-by-step breakdown of how this works:
1. **Gravitational Pull:**
- **Moon's Influence:** The Moon exerts a gravitational pull on Earth, which is strongest on the side of Earth closest to the Moon. This pull causes water on Earth to bulge towards the Moon, creating a high tide.
- **Sun's Influence:** The Sun also pulls on Earth's water, but since it's much farther away than the Moon, its gravitational effect on tides is about half as strong. However, when the Sun, Moon, and Earth align (during new and full moons), their combined gravitational forces produce higher high tides, known as spring tides.
2. **Centrifugal Force:**
- As Earth rotates, there's also a centrifugal force (an apparent force due to the rotation) that tends to push water away from the center of rotation. This results in another bulge on the opposite side of Earth from the Moon, also contributing to high tide.
3. **Resulting Tides:**
- **High Tides:** There are typically two high tides daily because Earth rotates, bringing any given point on Earth under the Moon's gravitational bulge twice in about 24 hours and 50 minutes (the lunar day).
- **Low Tides:** Between these high tides, water levels drop, leading to low tides. This happens because water is drawn away to form the high tide bulges.
4. **Types of Tides:**
- **Spring Tides:** Occur when the Sun, Moon, and Earth are aligned, increasing the tidal range (the difference between high and low tide).
- **Neap Tides:** Happen when the Sun and Moon are at right angles to each other, reducing the tidal range because the gravitational forces partially cancel each other out.
5. **Local Factors:**
- The shape of the coastline, depth of the ocean, and local geography can greatly influence the timing and height of tides in any given area. For example, in narrow bays or inlets, tidal amplitude can be significantly amplified, leading to very high or low tides.
6. **Tidal Periodicity:**
- Tides have a semi-diurnal nature in most places, meaning two high and two low tides occur each day. However, some regions experience diurnal tides (one high and one low tide per day) or mixed tides where the pattern isn't as regular.
7. **Other Influences:**
- Weather conditions like wind, atmospheric pressure, and even earthquakes or tsunamis can temporarily alter tide levels.
In summary, tides result from the gravitational dance between Earth, the Moon, and the Sun, modulated by Earth's rotation and local geography. This interaction creates the rhythmic rise and fall of sea levels that we observe daily.
Last edited:
Once I saw that, I signed right up. Excited to see the improvements on the way
