Tides Notes Handout
• Q: Why does the Earth experience tides?
A: The gravitational attraction of the Moon on the water of the Earth. The water
bulges toward the Moon, creating a high tide.
• Q: How do high and low tides occur?
A: The gravity from the Moon pulls on the water causing a bulge, and the Earth
itself is also pulled in that direction, creating a bulge on the opposite side. The
areas in between the bulges are the low tides.
• Q: How do spring and neap tides differ?
A: When the Earth, Moon, and Sun are in a straight line, the gravitational
attraction is at its greatest because of the additive property of gravity. This causes
a larger bulge of water. When the Earth, Moon, and Sun are in a perpendicular
configuration, the gravitational attraction of the Moon pulls counter to the Sun.
This causes a lower than normal bulge of water. There are only two neaps and two
springs in a month.
• Q: How often do tides occur?
A: Typically, there are two highs and two lows per day, every six hours.
• What are some advantages and limitations of the model we have been using?
Advantages:
Limitations:
• Q: How often do tides occur in one location?
A: Generally, there are four tides per day (ex; alternating high, low, high, low)
along the coast. This could vary according to location.
• Q: What pattern exists in the tides?
A: High tide is followed by low tide.
• Q: Would this pattern hold true throughout the remaining months of the
year?
A: Because the tides are related to the position of the Moon in relation to the
Earth, the pattern would repeat throughout the year.
• Q: During which phase of the moon are the tides the highest and lowest?
A: When the Sun, Earth, and Moon are in a straight-line configuration, the tides
are highest. This occurs during the new and full moon phases. This is called
Spring tide!
• Q: During which phase of the Moon is where there is not a large tidal range
(difference in distance) between High tide and low tide?
A: When the Sun, Earth, and Moon are in a perpendicular configuration (90o
angle), there is not a big change in tidal range. This occurs during the first and
third quarter moon phases. This is called Neap tide!
• When the Sun, Moon, and Earth are in a Straight line, we have a Spring
tide.
New Moon
Full Moon
• When the Sun, Moon, and Earth are perpendicular at a Ninety degree angle,
we have a Neap tide.
3rd Quarter
90o
90o
1st Quarter