Oh no ! Bad astronomy

[PeterStudz]

13 minutes ago, JOC said:

Mind you we've had a change in Government since then.

I've seen two kids at Uni. now (and neither have changed my mind that I didn't want to go to Uni.), but what is noticeable is how little time either spent in lessons/studying.  Were University course taught more intensely and for longer terms each year, each course would easily fit into two years, if not one!  This would bring with it commensurate savings for students in residential fees, even if they charged more for the more intense education it would still mean less in student loans for each student and they would be out in the big world earning and contributing that much quicker.

It was just the idea that a government, any group/organisation, could think like that.

I don’t think people need to go to university. Things are different now. When I went off to university only ~15% went.  Most of these were from private or grammar schools. I was in a comprehensive and out of my year at school literally a total of 6 went to university. That cannot be a good thing! 

I went because I wanted to study geology. At the time I couldn’t see any other way of doing that and getting paid (well, a full grant) for it. There was no loan, money from my parents etc. 

Edited July 10 by PeterStudz

[saac]

36 minutes ago, JOC said:

I am guessing adults!  I've just tried it and am about 10cm longer than a metre and knew without measuring it that it would be.

Estimating is a handy skill to have.  Unless you have a kid like my son who actually found the exact answers easier to work with than estimates and wasn't happy producing what they considered the more inaccurate answers.  Mind you I still like accuracy myself (I think it's why chemistry gelled and biology didn't).  I must admit I have a fair estimating eye and excellent spatial awareness.  I find I have a good visual grasp of will A fit into B, how long is X, if I roll that 3D shape around it my mind it will become that shape (I love those puzzles), can I fit that overhanging barrow full through that gate gap, will that bit of rolled up wire block that hole in a fence.  

This is the problem most pupils have to be honest. In reality, in the real world, estimates are crucial particularly in engineering where they are at the heart of the design process. Pupils are nervous at estimating because the have a false sense of faith in the term "accuracy", in truth, most will go through the entirety of their school years, college and university clinging to the "shoogly" understanding of accuracy.  A good estimate and more importantly, an understanding of the uncertainty in a value is often far more informative than the value itself. 

Your measurement, + 10 cm , is 90% of the target value. That is why when you sit in a car you are able to reach the various controls, or ride a bike and reach the handle bars, or sit reasonably comfortably in your train seat -  bless the engineers who had you in mind. That top shelf in the kitchen however will always be outwith your reach, sorry  

Jim 

Edited July 10 by saac

[JOC]

10 minutes ago, saac said:

Your measurement, + 10 cm , is 90% of the target value. That is why when you sit in a car you are able to reach the various controls, or ride a bike and reach the handle bars, or sit reasonably comfortably in your train seat -  bless the engineers who had you in mind. That top shelf in the kitchen however will always be outwith your reach, sorry  

Ah, I am worse at describing thing than I am at estimating.  My personal measurement comes in at approx. 110cm, so I make that 110% of the target value (depending on which way you look at it), and I can reach the top shelf, though not the containers on top of the cupboards!  That 6'2" son of mine with huge above average arms and legs just plucks the top of cupboard containers down as though they were on a table in front of him.

[AstroMuni]

54 minutes ago, JOC said:

but what is noticeable is how little time either spent in lessons/studying. 

That depends on the course I think. Some courses require spending time not just in teacher led classes but also in practical workshop type classes, many of which are conducted late in the evenings and then they also have group projects that demand a lot of work after classes.

[JOC]

NB.  If you are interested in sundials the wikipedia page is fascinating https://en.wikipedia.org/wiki/Sundial#:~:text=To be accurate%2C such a,must equal the local latitude.

[ollypenrice]

On 10/07/2024 at 11:24, PeterStudz said:

Alice was recently asked by one of her school friends “what’s the point of astronomy?”, which she could not answer. For me the answer is within the quote above. 

The point of astronomy can only be only be grasped by those sufficiently intelligent to know already.

Olly

[Xilman]

On 09/07/2024 at 10:41, M40 said:

Reading the above reminded me, has anyone else got "the look" when you mention every star you can see is in our galaxy?

SN1987a was easily visible to the naked eye though, to be fair, it no longer is.

With a decent aperture, yet still well within range of those owned by many amateurs, individual stars in M31 (and perhaps M33 - I'm not sure) are readily visible. I first saw AE And back in the late 1980s. Some VS observers, Gary Poyner is an example)  often make estimates down to below mag 16.

With really quite small telescopes, individual stars in the SMC and LMC are also quite easy to see.

[Xilman]

1 hour ago, ollypenrice said:

The point of astronomy can only be only be grasped by those sufficiently intelligent to know already.

Olly

An alternative and often seen version runs: To those who understand, no explanation is necessary; to those who do not understand, no explanation is possible.

[Xilman]

On 10/07/2024 at 11:13, saac said:

Pupils are nervous at estimating because the have a false sense of faith in the term "accuracy", in truth, most will go through the entirety of their school years, college and university clinging to the "shoogly" understanding of accuracy.

Try getting them to understand the difference between accuracy and precision. I often see people computing and presenting the results to a ludicrous number of figures, even though the data going into the computation is only good to two or three figures.

[pipnina]

10 minutes ago, Xilman said:

SN1987a was easily visible to the naked eye though, to be fair, it no longer is.

With a decent aperture, yet still well within range of those owned by many amateurs, individual stars in M31 (and perhaps M33 - I'm not sure) are readily visible. I first saw AE And back in the late 1980s. Some VS observers, Gary Poyner is an example)  often make estimates down to below mag 16.

With really quite small telescopes, individual stars in the SMC and LMC are also quite easy to see.

This reminds me of how much I love the Hubble mega mosaic of M31, individual stars are basically all that's seen, you can even see galaxies in the background *through* the main disc which is insane.

[Pompey Monkey]

16 hours ago, Xilman said:

Try getting them to understand the difference between accuracy and precision. I often see people computing and presenting the results to a ludicrous number of figures, even though the data going into the computation is only good to two or three figures.

I'm an engineer and I can verify:

π = 3,

C = 1 foot per nanosecond = 3×10^8 m/s,

Sin x = x for small angles etc.

 

It also pains me immensely when I see results presented to more significant digits than the accuracy of the inputs permits. It's amazing how many engineers just can't grasp the concept of CICO!

[Xilman]

On 13/07/2024 at 10:50, Pompey Monkey said:

I'm an engineer and I can verify:

π = 3,

C = 1 foot per nanosecond = 3×10^8 m/s,

Sin x = x for small angles etc.

g (in m/s/s) = pi^2 = 2^3 =10 is amazingly useful.

c is the the resultant velocity of accelerating at 1g for a year (in the Galilean approximation of course). It is no coincidence that the radius of curvature of spacetime at the Earth's surface is one light year.

 

[Pompey Monkey]

2 hours ago, Xilman said:

It is no coincidence that the radius of curvature of spacetime at the Earth's surface is one light year.

 

I have no idea how to use that, or what it even means.

But it sounds cool. 🤣

Did you know that the speed of sound at ses level is 1/10^6 that of light in a vacuum?

[Mandy D]

 

11 minutes ago, Pompey Monkey said:

Did you know that the speed of sound at ses level is 1/10^6 that of light in a vacuum?

No, it is not.

Speed of sound at sea level = 343 ms^-1

c = 299  792 458 ms^-1

[saac]

6 minutes ago, Mandy D said:

 

No, it is not.

Speed of sound at sea level = 343 ms^-1

c = 299  792 458 ms^-1

Or 1.44 - so in order of magnitude yes 1/1000000 th of the speed of light. Significant figures and all that  

Jim 

[saac]

We do a rather cool investigation to calculate the speed of sound in school. We go out into the playing field where two pupils carrying a set of rather large cymbals walk to the opposite end of the field. They are also carrying a mobile phone so we can talk to them once everybody is in position. Once given a visual signal they crash the cymbals together over their head so we can clearly see the moment of impact. The remainder of the pupils who are standing some 300m away are generally surprised to experience the time delay between seeing the cymbals crash and then hearing the sound. The smiles grow bigger when we have the phone line open, we first see the cymbals crash, then hear the noise over the phone and then again as it reaches us over the open ground. Measuring the average time delay gives a good approximation to the speed of sound. 

Jim 

[Stu]

On 09/07/2024 at 11:13, saac said:

I get the look when I announce I need another telescope to see more stars  

Jim 

I see more stars when the lovely Mrs Stu bats me round the head with the frying pan after another scope or eyepiece arrives! 🤪