Moon, Tides, and Eclipses
Define crescent
A crescent is a sliver of the moon along one edge. Occurs right after or right before the New Moon.
Define gibbous
A gibbous is an almost full moon with only a crescent of darkness. Occurs right after or right before the Full Moon.
What is a partial eclipse?
A partial eclipse is when the moon is partially in the umbra, completely in the penumbra, or only partially in the penumbra.
Define penumbra
A penumbra is the lighter part of a shadow.
Define perigee
A perigee is the point in the moon's orbit where it is the closest to Earth.
What is a total eclipse?
A total eclipse is when the moon is completely in the umbra.
Define apogee
An apogee is the point in the moon's orbit where it is farthest away from Earth. "A" for Away.
What does eclipse mean?
An eclipse is when one celestial body blocks out the light from another celestial body
Define umbra
An umbra is the darkest part of a shadow.
Describe the range of the high and low tides during a spring tide.
During a spring tide, there is the greatest range of water level between the high tide and the low tide. The spring tide results in the highest high tide and lowest low tide because of the extra gravitational pull "helping" the moon pull on the Earth's oceans.
Describe the range of the high and low tides during a neap tide.
During the neap tide, there is the lowest range between high tide and low tide.
Why does earth always see the same side of the moon?
Earth always sees the same side of the moon because it takes the moon the same amount of time to complete a rotation on its axis as it does to complete a revolution around the Earth. If you imagine a flag on the moon, as the moon revolves around the Earth, the flag/moon is also rotating at just the right speed so that the flag is always pointing towards the Earth.
In general, how many high and low tides are there in a day?
In general, there are 2 high and 2 low tides in 24 hours. They exchange every 6 hours.
Although our sun has a stronger gravitational force on earth than our moon, why are our ocean tides influenced more by the moon than by the sun?
Ocean tides are influenced more by the moon than by the sun because although our sun has greater mass and therefore greater gravity, gravity is also affected by distance, so the moon has a stronger gravitational pull on the ocean than the sun does because the moon is much closer to Earth.
Solar eclipses and lunar eclipses occur about two weeks apart. Explain why (using your knowledge of moon phases)
Solar eclipses and lunar eclipses occur about two weeks apart because the earth, moon, and sun must be on the same 'plane' or 'level' in order for an eclipse to occur. Therefore, after a lunar and solar eclipse, the moon continues to revolve around the Earth on the same level it just was, therefore approaching the position of a lunar or solar eclipse.
Why doesn't earth see an eclipse every time there is a new or full moon?
The Earth does not see an eclipse every time there is a new of full moon because in order for an eclipse to occur, all 3 celestial bodies must be lined up. However, since the moon's orbit is tilted, they are not always lined up come the new and full moons.
What is blocked during a lunar eclipse?
The light from the sun is blocked from reaching and reflecting off the moon. (However, the moon is still visible and has a reddish tint because the light from the atmosphere refracts and bounces off of the moon.)
How long does it take for the moon to complete a rotation on its axis?
The moon 29.5 days to complete a rotation on its axis
What force influences tides?
The moon and sun's gravity influence tides, as well as the position of the moon. However, because the moon is much closer to the Earth than the Sun, it is mostly the gravitational pull of the moon that influences the tides.
A. What phase is the moon in? B. What is blocked from earth's view? C. What is causing it to be blocked? D. Who can see the solar eclipse?
The moon is in its new moon phase. The sun's light is blocked from the Earth's view. The moon is blocking the sun. Everyone in the umbra can see the total solar eclipse, and everyone in the penumbra can see a partial solar eclipse.
a. State the 2 possible positions of the earth, sun, and moon. b. How many bulges are there? c. What is causing each tidal bulge? d. What do you notice about the ocean at a 90 degree angle from the bulges?
The sun, moon, and Earth must all be aligned, and the moon can either be in the full moon or new moon position. There are 2 tidal bulges. The pull of the sun and/or moon on the oceans, as well as the sun and/or moon's pull of the actual Earth causes the tidal bulges. At a 90 degree angle from the bulges, the ocean is at its lowest point.
How often do eclipses occur?
Total eclipses occur approximately every 18 months.
When the moon is in its apogee, what happens to the tides?
When the moon is in its apogee, all tides become a bit lower.
When the moon is in its perigee, what happens to the tides?
When the moon is in its perigee, all tides become a bit higher.
Define waning
"Waning" moon phases occur as the moon is "shrinking" in the sky. We are "waning" goodbye. These stages occur AFTER the Full Moon
Define waxing
"Waxing" moon phases occur as the moon is "growing" in the sky. Waxing light is on the right. These stages occur AFTER the New Moon.
Why do we see moon phases
(1) the sun illuminating half of the moon, and (2) the moon's position around the Earth.
a. Using degrees, describe the position of the moon and sun in relation to the earth. b. Where do the tidal bulges occur? What does this show about the gravitational force of the moon on tides in comparison to the sun? c. Describe how the bulges are different than in spring tide. Why are they so different?
If you were to draw a line from the moon to the center of the Earth, and then a line from the sun the the center of the Earth during a neap tide, you would see that they create a 90 degree angle. The large tidal bulges occur on the side of the moon, and the opposite side of the moon. These large tidal bulges are caused by the moon's pull on the Earth oceans, and the moon's gravitational pull on the actual earth, leaving a bulge on the opposite side. The smaller tidal bulges occur on the side of the sun, and the side opposite the sun. These small tidal bulges are caused by the sun's (weaker) gravitational pull on the oceans, and on the physical Earth itself. These tidal bulges are different from the spring tide bulges for 2 reasons. The large tidal bulges occur at a 90 degree angle to the sun, instead of being inline with the sun. The largest tidal bulges are smaller, and the smallest tidal bulges are larger. This is because during the spring tide, the sun's gravity is "helping" the moon to pull the oceans and the Earth. However, during a neap tide, the sun is at a 90 degree angle with the moon and is therefore working against the moon's gravity to create a lower high tide, and therefore much less of a range between high tide and low tide. The moon still pulls the oceans higher than the sun can because it is closer and therefore has a stronger gravitational pull on the Earth's oceans.
A. What phase is the moon in? B. What is blocked from earth's view? C. What is causing it to be blocked? D. Who can see the lunar eclipse?
The moon is in its full moon position. The light from the sun reflecting off the moon is blocked from the Earth's view because the sun can't reach the moon. Therefore, the only light comes through the Earth's atmosphere, giving it a red tint. The Earth is blocking the sun's light from the moon. Everybody in the umbra (which is everybody in nighttime) can see the lunar eclipse.
explain why the moon phases are occurring
The moon phases occur due to (1) the sun illuminating half of the moon, and (2) the moon's position around the Earth. As the moon changes its position, the angle that we are viewing the illuminated half of the moon changes. This causes us to only see crescents, for example, at certain angles. As you move up or down the latitude lines, the angle also changes, and so the moon can appear "tilted" in comparison to other latitude lines at the same time.
In what direction does the moon revolve around the earth?
The moon revolves around the Earth in a counterclockwise direction.
How long is the revolution of the moon around the earth?
The moon takes 29.5 days to revolve around the Earth.
What is blocked during a solar eclipse?
The sun's light is blocked from reaching the Earth during a solar eclipse.