Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Mjhavok on 13/08/2006 21:53:21
-
Suppose that the nucleus of an oxygen atom, which has 8 protons and usually has 8 neutrons, were split exactly in two. What element would be the result? How many atoms of this element would there be? Neglect, for simplicitym any energy that might be involved in the reaction.
-Steven
In a time of universal deceit - telling the truth is a revolutionary act.
-
Helium(4) isotope: 2 protons and 2 neutrons.
-
No
-
It doesn't take much to divide 8 by 2, look up atomic number 4 on a periodic table, and come back with the answer Beryllium.
George
-
Hehe yep. It makes a rare isotope of beryllium. It turns out that the most common isotope of beryllium has five neutrons in its nucleus.
-
Physics Question of the Week
What is the critical angle for light rays shining upward from beneath a fresh water pond?
-Steven
-
You didn't expect me to know this off the top of my head did you? Unfortunately, google all too easily replies that the critical angle to an air/water interface is 48.6 degrees (although this must depend upon purity of the medium, temperature and pressure of the medium, and even the colour of the light).
George
-
quote:
Originally posted by another_someone
It doesn't take much to divide 8 by 2, look up atomic number 4 on a periodic table, and come back with the answer Beryllium.
George
Right. My mistake. I'm sorry.
-
quote:
Originally posted by Mjhavok
Physics Question of the Week
What is the critical angle for light rays shining upward from beneath a fresh water pond?
-Steven
SIN(i)/SIN(r) = 1/n(H2O); n(H2O) = 1.336 at 550 nm (according to http://www.philiplaven.com/p20.html); r = 90° --> i = 48.48°. In the entire visible spectrum it varies from about 48.1° (violet) to 48.7° (red).
-
Answer is 48.8°
Given that the angle in this situation is defined with respect to the normal to the surface, not with respect to the plane of the surface.
I didn't give enough variables to allow you to be more accurate. 48.7 and 48.6 are close enough.
Well done.
-
PHYSICS QUESTION OF THE DAY (IT SEEMS LOL)
The geomagnetic field is produced by what?
Steven
_______________________________________________________________
In a time of universal deceit - telling the truth is a revolutionary act.
-
The movement of a condutive fluid (probably Iron) relative to the rtation of the earth in a layer immediatly above the earths solid core.
syhprum
-
quote:
Originally posted by syhprum
The movement of a condutive fluid (probably Iron) relative to the rtation of the earth in a layer immediatly above the earths solid core.
Just to Add: this movement happens in the presence of a magnetic field, and this produces an electric current, that, in turns, produces a magnetic field that reinforces the first, regenerating it (Dynamo theory).
How this can happen is however still a mistery for me, because, usually, an induced magnetic field is opposite to the first one (inducer).
The first (igniting) magnetic field could have been, for example, the one of another planetary object near the earth millions of years ago.
-
It is well established that the earth early in its history was in collision with a mars sized object (Mars?) that lead to the creation of our moon, could this be the seed of the magnetic field?
syhprum
-
The movement of a condutive fluid (probably Iron) relative to the rtation of the earth in a layer immediatly above the earths solid core.
syhprum
-
quote:
Originally posted by syhprum
The movement of a condutive fluid (probably Iron) relative to the rtation of the earth in a layer immediatly above the earths solid core.
Just to Add: this movement happens in the presence of a magnetic field, and this produces an electric current, that, in turns, produces a magnetic field that reinforces the first, regenerating it (Dynamo theory).
How this can happen is however still a mistery for me, because, usually, an induced magnetic field is opposite to the first one (inducer).
The first (igniting) magnetic field could have been, for example, the one of another planetary object near the earth millions of years ago.
-
It is well established that the earth early in its history was in collision with a mars sized object (Mars?) that lead to the creation of our moon, could this be the seed of the magnetic field?
syhprum
-
quote:
Originally posted by syhprum
It is well established that the earth early in its history was in collision with a mars sized object (Mars?) that lead to the creation of our moon, could this be the seed of the magnetic field?
syhprum
Dont know but the way i see it is its got to have been a contributing factor as to why the magnetic field is still so strong today as the colision must have added heat to the outer core helping it stay liquid for so long.
Michael
-
The movement of a condutive fluid (probably Iron) relative to the rtation of the earth in a layer immediatly above the earths solid core.
syhprum
-
quote:
Originally posted by syhprum
The movement of a condutive fluid (probably Iron) relative to the rtation of the earth in a layer immediatly above the earths solid core.
Just to Add: this movement happens in the presence of a magnetic field, and this produces an electric current, that, in turns, produces a magnetic field that reinforces the first, regenerating it (Dynamo theory).
How this can happen is however still a mistery for me, because, usually, an induced magnetic field is opposite to the first one (inducer).
The first (igniting) magnetic field could have been, for example, the one of another planetary object near the earth millions of years ago.
-
It is well established that the earth early in its history was in collision with a mars sized object (Mars?) that lead to the creation of our moon, could this be the seed of the magnetic field?
syhprum
-
quote:
Originally posted by syhprum
It is well established that the earth early in its history was in collision with a mars sized object (Mars?) that lead to the creation of our moon, could this be the seed of the magnetic field?
syhprum
Dont know but the way i see it is its got to have been a contributing factor as to why the magnetic field is still so strong today as the colision must have added heat to the outer core helping it stay liquid for so long.
Michael
-
i don't think that the theory is that well-established, since there are several, equally viable, competing theorys on the formation of the moon.
earth is very large for a rocky planet, so it's no surprise, really, about the outer core staying liquid. a collision would be unlikely to add a significant ammount of heat to the outer core and not other parts of the planet, as far as i can understand. perhaps you could clarify this conjecture?
-
quote:
Originally posted by bostjan
i don't think that the theory is that well-established, since there are several, equally viable, competing theorys on the formation of the moon.
earth is very large for a rocky planet, so it's no surprise, really, about the outer core staying liquid. a collision would be unlikely to add a significant ammount of heat to the outer core and not other parts of the planet, as far as i can understand. perhaps you could clarify this conjecture?
The collision theory is the main and most widely accepted theory for the creation of the moon for many reasons. To name a few, the moon and earth are the same age. The earth is tilted due to a very large impact and the makeup of the moon which has very little iron as most of it would have been propelled into the earth during the impact. Their are other
Michael
-
quote:
Originally posted by ukmicky
quote:
Originally posted by bostjan
i don't think that the theory is that well-established, since there are several, equally viable, competing theorys on the formation of the moon.
earth is very large for a rocky planet, so it's no surprise, really, about the outer core staying liquid. a collision would be unlikely to add a significant ammount of heat to the outer core and not other parts of the planet, as far as i can understand. perhaps you could clarify this conjecture?
The collision theory is the main and most widely accepted theory for the creation of the moon for many reasons. To name a few, the moon and earth are the same age. The earth is tilted due to a very large impact and the makeup of the moon which has very little iron as most of it would have been propelled into the earth during the impact.
Michael
-
wouldn't mars have to be significantly older than earth for that to happen, though? 4.5 billion years ago, mars was still in its infancy, and would have been pretty darn soft itself.
moon rocks are not really similar in composition enough for me to believe that the moon is made from the earth, but if it is, i think the ejected ring theory is just as valid as the colling planet theory.
-
wouldn't mars have to be significantly older than earth for that to happen, though? 4.5 billion years ago, mars was still in its infancy, and would have been pretty darn soft itself.
moon rocks are not really similar in composition enough for me to believe that the moon is made from the earth, but if it is, i think the ejected ring theory is just as valid as the colling planet theory.