Good morning and welcome to this week's #iteachphysics chat. Today our topic is the Sun-Earth-Moon system (astronomy and physics), the lunar calendar, Ramadan, and other cultural and educational connections
Good morning and welcome to this week's #iteachphysics chat. Today our topic is the Sun-Earth-Moon system (astronomy and physics), the lunar calendar, Ramadan, and other cultural and educational connections
Before we get started let's do an #iteachphysics roll call. Please tell us where you teach physics and what level of students. Please remember to use the hashtag in all your tweets.
Before we get started let's do an #iteachphysics roll call. Please tell us where you teach physics and what level of students. Please remember to use the hashtag in all your tweets.
Before we get started let's do an #iteachphysics roll call. Please tell us where you teach physics and what level of students. Please remember to use the hashtag in all your tweets.
Here we go with #iteachphysics Q1. Please everyone, feel free at any time to ask your own Qs to @NidhalGuessoum or anyone else in the chat, or offer your own answer to any question.
Here we go with #iteachphysics Q1. Please everyone, feel free at any time to ask your own Qs to @NidhalGuessoum or anyone else in the chat, or offer your own answer to any question.
#iteachphysics Q1: @NidhalGuessoum Let's first set a baseline of understanding the orbital mechanics in the Sun-Earth-Moon system. What are some good didactics there?
#iteachphysics Q1: @NidhalGuessoum Let's first set a baseline of understanding the orbital mechanics in the Sun-Earth-Moon system. What are some good didactics there?
Ekementary school teacher in the Toronto area, not currently teaching science but happy to learn and connect other #stem educators to culturally responsive education 🌍🌎🌏#iteachphysics
Well it's useful to remember that our moon is big -- relatively. Except for Pluto's Charon, our moon is - compared to its planet - the largest in the solar system. Our Moon is 1/80th the mass of Earth; Ganymede, the largest moon in the solar system is 13,000 smaller than Jupiter.
Well it's useful to remember that our moon is big -- relatively. Except for Pluto's Charon, our moon is - compared to its planet - the largest in the solar system. Our Moon is 1/80th the mass of Earth; Ganymede, the largest moon in the solar system is 13,000 smaller than Jupiter.
And so we experience substantial tides, which has differential forces between the nearer side and farther side, and we also experience eclipses.. because our Moon happens to have a diameter that is 400 times smaller than the sun and is at a distance also 400 times closer than Sun
There's something interesting here: if we calculate the force of gravity from the Sun on the Moon we find it more than twice stronger than the force from Earth on the Moon. But that's misleading. Because the Earth itself is pulled by the Sun, so what matters is the differential.
And so in effect, the Sun's contribution to the problem is only about 1.5 %. Still important to affect the orbit of the moon, its appearance, when New Moon occurs, etc.
And to complicate things further, one must include the effects of planets and non-sphericity of Earth and Moon.
There's something interesting here: if we calculate the force of gravity from the Sun on the Moon we find it more than twice stronger than the force from Earth on the Moon. But that's misleading. Because the Earth itself is pulled by the Sun, so what matters is the differential.
#iteachphysics The Moon is tidally locked, meaning it's always showing us the same face. (There's some subtle effects there, I can come back to this.) And this is due to the Moon's rotation around itself being equal to its revolution period around Earth (both 27.3 days).
What's interesting is that the Moon has slowed down in its rotation since its formation due to mutual tidal forces with Earth. Now that its rotation period is equal to its revolution period, it is "happy", no more slow down. But it continues to recede from Earth. #iteachphysics
Sure. What happens, in a nutshell, is that the Earth rotates much faster (1 day) than the Moon (27.3 days) so it's tidal bulge moves forward, trying to pull the Moon, which reacts by pulling it backward, thus creating friction, which then slows down Earth...
#iteachphysics
And because Earth slows down (by 23 microseconds a year, or 38 minutes every 100 million years), it must push out the Moon since Angular Momentum must be conserved.
#iteachphysics
The phase of the moon is essentially the same at any point on earth on a given night. Even between two extreme places (say 12 hours apart, like between here in the UAE and California), the Moon will not have changed much in appearance.
#iteachphysics
I wish there was enough time in my semester, it would have been cool to go through such incredible #physics details with my #iteachastronomy students. A lot to cover in such a short amount of time. #iteachPhysics
Having said that, calculating the phase of the moon can be done using just formulas or going back to first-principles of physics. Formulas are available in a number of books (Meeus is the most straightforward but has no physics or explanations) or websites...
#iteachphysics
This actually brings to mind two #iteachphysics Qs,
1) is there a connection btwn tidal locking and how the lunar calendar is understood?
2) how can we connect early planetary science education in Gregorian calendar societies vs lunar calendar ones?
In reply to
@HandsOnilm, @NidhalGuessoum, @rjallain
But using fundamental equations of physics is quite a bit more complicated, because all kinds of approximations must be made to simplify the calculation and then program them and run the code... But they're just Newton's equations, albeit in 3-D, with angles, etc.
#iteachphysics
Yes, the same equations or formulations can be used to plug any time t, forward or backward and determine the phase of the moon on any date. And that has been done to investigate historical claims (eclipses, battles, etc.)...
#iteachphysics
How's this? An animation, no commentary. A great way to provoke student curiosity and questions about the Earth Moon Sun System?
#ITeachPhysicshttps://t.co/6IPwsX8F0L
In reply to
@NidhalGuessoum, @BlackPhysicists, @rjallain
The lunar calendar just uses phases. I don't think the tidal locking plays a role. At least I haven't thought of it that way. Maybe there's something to that. Not absolutely sure, but I don't think...
#iteachphysics
In reply to
@BlackPhysicists, @HandsOnilm, @rjallain
Yes, the same equations or formulations can be used to plug any time t, forward or backward and determine the phase of the moon on any date. And that has been done to investigate historical claims (eclipses, battles, etc.)...
#iteachphysics
It's quite interesting educationally to explain why the lunar calendar prospered in history and remains used to this day, at least for religious cultures... mainly that it's easy to tell the start of a month just by looking at the moon -- not the case with the sun.
#iteachphysics
In reply to
@BlackPhysicists, @HandsOnilm, @rjallain
That's actually pretty awesome b/c it invokes thinking about the Sun's corona, which is what we see during eclipses. #iteachphysics Thanks for sharing.
In reply to
@HandsOnilm, @NidhalGuessoum, @rjallain
For calculations, one should go back to the fundamental books.
I've mentioned Jean Meeus's book, has formulas for every astronomical phenomenon one can think of, a favorite of amateurs and professionals alike.
There's also Kim Long's The Moon Book, short and nice.
#iteachphysics
For lunar phases and calendars, one can go to some websites, such as https://t.co/XM7MaYImhp and https://t.co/KTABuZ9m15. Mooncalc has an app; Icoproject has a little free softwarae 'Accurate Times' for moon phases, Islamic calendar, etc.
#iteachphysics
#iteachphysics Q6.0: @NidhalGuessoum Obviously cloud cover can prevent naked-eye sightings of the crescent of the New Moon. Are there any other reasons why one may not be able to see it?
Indeed. What we must realize is that even if the sky is clear and the crescent (in its first night) is above the horizon, we may not see it. In its first 24 hours, the crescent is too thin and too faint (compared to the background sky) to be seen by human eyes.
#iteachphysics
Add to that other hindering factors, such as dust (in sandy regions) or chemical pollution (in industrial areas) or humidity (near coasts) or light pollution (after dusk)...
#iteachphysics
Yes, does #Ramadan start this Wed or Thurs? Depends on each community's decision to stick with astronomical calculation or visual sighting methods or a combo. I wait in anticipation!
#iteachPhysics
I feel that students in introductory astronomy should be exposed to more of the cultural connections than astrophysical connections because they are more tangible and socially relevant. #iteachastronomy
In reply to
@NidhalGuessoum, @BlackPhysicists, @HandsOnilm, @rjallain
The new crescent that starts an Islamic month like Ramadan will be seen in the western sky after sunset by about 30 to 60 minutes. It's important to have a clear horizon, and little of the hindering factors I mentioned earlier...
#iteachphysics
I feel that students in introductory astronomy should be exposed to more of the cultural connections than astrophysical connections because they are more tangible and socially relevant. #iteachastronomy
In reply to
@NidhalGuessoum, @BlackPhysicists, @HandsOnilm, @rjallain
#iteachphysics Q7.0: The global interest in astronomy and Ramadan brings to mind the possibility to connecting classrooms around the world in learning about the Sun-Earth-Moon system.
Too many don’t know the date of Easter is intimately connected to astronomy and know even less about significant observances in other cultures. Plus, calendar mathematics is fascinating! #iteachastronomy
In reply to
@NidhalGuessoum, @BlackPhysicists, @HandsOnilm, @rjallain
Good question! Because the moon is close to sun (remember it's early in the lunar month, it has just crossed the plane between Earth and Sun), so as the sun sets, the moon follows shortly after. On the first night of the lunar month, the crescent doesn't stay long.
#iteachphysics
#iteachphysics following the Islamic calender at 14th of the each month we experienced full moon, then the moon starts to shrink till it disappeared on the 29th so what causes this?
#iteachphysics Q8.0: Astronomy has the virtue of forcing people to think about a common humanity in a Universe of so much more than ourselves.
See Astronomy and Civilization in the New Enlightenment: Passions of the Skies https://t.co/DeboM0CJn1
Good question! Because the moon is close to sun (remember it's early in the lunar month, it has just crossed the plane between Earth and Sun), so as the sun sets, the moon follows shortly after. On the first night of the lunar month, the crescent doesn't stay long.
#iteachphysics
There are of course numerous possible reasons why an observation might get missed?! But in this case I would say that without contrast sighting ain't happening...
#iteachphysics Q8.0: Astronomy has the virtue of forcing people to think about a common humanity in a Universe of so much more than ourselves.
See Astronomy and Civilization in the New Enlightenment: Passions of the Skies https://t.co/DeboM0CJn1
Project based learning ,that is web-based, such that classrooms around the world (digital divide issues notwithstanding) can participate. It's a term I'm taking from @PSRastronomer#iteachphysics
In reply to
@HandsOnilm, @PSRastronomer, @awb_org, @IAU_Outreach, @PSRastronomer
#iteachphysics Q9: @NidhalGuessoum Ramadan calls upon its observers to exhibit certain virtues. But they are virtues that we should try in inculcate always in all our students. What are some ways where can teach physics for a civil society?
#iteachphysics Q9: @NidhalGuessoum Ramadan calls upon its observers to exhibit certain virtues. But they are virtues that we should try in inculcate always in all our students. What are some ways where can teach physics for a civil society?
Even an exercise where students calculated calendars based on different schemes, e.g., Gregorian, lunar, etc. would be a great exercise with all kinds of global education implications. Not to mention the physics paces it would take students through #iteachphysics
In reply to
@HandsOnilm, @PSRastronomer, @awb_org, @IAU_Outreach
A8.1 Both inquiry based #STEM learning and the current trend of culturally responsive pedagogy can guide K-12 science education towards content that is inclusive, not exclusive = important for educators who prioritise social justice education
#iteachphysics
Cc #Educolor
