Full moon friday

[Undodog]

A girl who sits near me in my office just tried to explain that the full moon affects people because we humans are 90% water.

I was going to say, “Well firstly, the moon doesn’t affect the ocean just because it’s made of water. If it was made of oil we would still get tides but by your rationalisation we wouldn’t be affected because we are not 90% oil. With the exception of Peter Stringfellow.
Secondly the difference between a full moon, half moon, crescent moon etc. has nothing to do with the oceans whatsoever.”

But I had to answer the phone and lost the moment.
:(

[davidhorman]

Secondly the difference between a full moon, half moon, crescent moon etc. has nothing to do with the oceans whatsoever.

Aren't tides higher during full moons and new moons, and lowest at the half-crescents? Or was that not what you were getting at?

David

[Undodog]

Are they? why?
Unless when the moon is full, there is more of it!;)

[thaiboxerken]

Aren't tides higher during full moons and new moons, and lowest at the half-crescents?

Why would they be? The amount of sunlight shining on the moon has no bearing on the moon's gravitational pull.

[Marian]

How the moon and tide thing all works:

http://science.howstuffworks.com/question72.htm

:D

[davidhorman]

Why would they be? The amount of sunlight shining on the moon has no bearing on the moon's gravitational pull.

I'm not suggesting that the moon's phase is the cause of the variation in tides :D But the variation in tides shares the same cause as the moon's phase - the sun. When the sun and moon are aligned (at full moon, new moon, or in the extremes at lunar eclipse or solar eclipse), the slight additional pull of the sun makes the high tides higher and the low tides lower (a spring tide). When the sun and moon are at ninety degrees with respect to the earth, the tides are less extreme (neap tides).

David

[Grommitt]

Originally posted by Undodog
.
Secondly the difference between a full moon, half moon, crescent moon etc. has nothing to do with the oceans whatsoever.
Not quite correct.

Tides are always higher at full and new Moon and lowest at crescent phase. Not because of the appearance of the Moon but because of the influence of the the Sun.

The Sun influences the tides less than half that of the Moon but enough so that when the Sun, Earth, and Moon are lined up at new and full Moon, the tides are higher. This is called "spring" tide (nothing to do with the seasons). At crescent Moon, the Sun, Earth, and Moon are at right angles and the result is called the "neap" tide which is the lowest.

The appearance of the Moon has, of course, nothing to do with the tide. It is strictly the position of the three bodies.

BTW, Our Moon is always capitalized since that is its proper name.

This site (http://csep10.phys.utk.edu/astr161/lect/time/tides.html) has a good illustration of the tidal effect.

[Undodog]

But the moon can be full as seen (if you could see it at the same time) from Mexico, Egypt or Japan can't it?*
So the only difference in these places is the tide and not the phase of the moon.

edited to add: oh right yeah.. like you said. :)

*Bear with me, they gave us free drinks at dinner.

[Dancing David]

I think the probelm is that there are associations in biology that could be related to the lunar cycle and people just assume because they are similar that they are derivative. The daily circadian cycle is very close to the lunar 'day', in that without enviromental cues the cycle runs a little longer than a solar day(these studies were about twenty years ago and could have been not replicated), and then the avaerage menses is also the lenth of a lunar month.

But coincidence, biology or derivation?

[The Bad Astronomer]

Y'all are missing the big point: tides are caused by the change in the force of gravity with distance. The Earth is big enough compared to its distance from the Moon that we get tides (8000 miles versus 240,000). A human is too small to get appreciable tides. 6 feet of difference just isn't enough to measure versus 240,000 miles!

[Yahweh]

Originally posted by Undodog
A girl who sits near me in my office just tried to explain that the full moon affects people because we humans are 90% water.
Not quite...

The moon affects people because we're supersticious...

[Jeff Corey]

Must be a full moon.
A Moonie came to our door, so we had him in for brunch.
Tastey, but a bit dry.

Who can detect the Correlation Implies Causality phallacy earlier, here?

No fair, Phil.

[Jeff Corey]

Originally posted by The Bad Astronomer
Y'all are missing the big point: tides are caused by the change in the force of gravity with distance. The Earth is big enough compared to its distance from the Moon that we get tides (8000 miles versus 240,000). A human is too small to get appreciable tides. 6 feet of difference just isn't enough to measure versus 240,000 miles!
I use the old "That crack pipe in your hand has more gravitation influence on you than the moon, sun, or Uranus.

[TAILGUNNER]

Where does the term lunatic come into play regards the luna cycle?

[Paul C. Anagnostopoulos]

The word lunatic got made up when people thought that the moon could affect people's personalities.

Oh, wait . . .

~~ Paul

[Paul C. Anagnostopoulos]

Undodog said:
But the moon can be full as seen (if you could see it at the same time) from Mexico, Egypt or Japan can't it?
The moon looks the same everywhere. No?

~~ Paul

[TAILGUNNER]

Thanks i wasnt sure but was thinking along those lines

Well that and from observation a mental illness does come and go in cycles similar to the moons phases (though not obviously running alongside)

[Mercutio]

I used to live on Lake Erie...but any big lake will do. Ask your friend to go to any lake in the world and measure the tide. There is (for all practical purposes) none. Then have your friend note how much bigger this lake is than any single unbound body of fluid in your body (let alone in your brain, which most will agree is more to the point). Ask your friend also to note that the lake tends to stay in one place for long periods of time--that is, the lake is not likely to make a ninety degree turn in its bed as you watch. Then....point over your friend's shoulder, and watch as the tidal forces suddenly hit your friend's brain (and body) from a completely different direction as your friend turns to follow your finger. Any tidal effect will be changed every time you turn your head! (note: this assumes the tidal explanation to be true...if you want to get into mass, distance, etc., you have an entirely new set of variables to have fun with...)

[Terry]

Originally posted by Undodog
Are they? why?
Unless when the moon is full, there is more of it!;)

The sun causes tides (which are much smaller than the moon's tides). At full or new moon, the sun tides are in phase with and add to the moon tides.

--Terry.