This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

It Just Is

I wonder how much of what we 'know' has ever been properly explained? Our teachers repeat what they have been taught and our text books are re-writes of earlier text books. Perhaps that is the way to pass exams, don't think about what is missing, just repeat what was taught and so it goes on.


Lately I have been looking through some of my old 'how it works' books from my childhood, encyclopedias, atlases and 'online' to see what they say about the Earth's seasons. At least they all agree! It is all down to the tilt of the Earth's axis, the northern hemisphere points towards the Sun in the summer and away from the Sun in winter. Simple! We don't need to know anything more.


A simple experiment: Take a dinner plate and place an apple near the rim with its stalk pointing slightly towards the centre, a model of the tilted Earth. Now slowly and carefully twist the plate on top of a table so as not to disturb the apple until the plate has turned through 180 degrees. Now which way is the apple pointing? Do you still understand the seasons or did you have a book/teacher that really explained it? Perhaps you are a heretic and thought for yourself? Andy Millar raised some of these issues in "You don't need practical skills to be an engineer", 'knowing' how to do something can stop new thinking.


Have a virtual mug of coffee and think about it!
Parents
  • James,

    I am afraid I don't understand your point with this. The gravitational attraction between the sun and the earth acts (more or less, discounting tidal forces) equally on all of the earth. With your weights and string analogy the force acts at the point the string is attached to the weight. You then lose me with the "Any axis one chooses to define between these satellites". I am not an expert in celestial mechanics but I know enough to understand what is happening to the planets, though perhaps not enough to make a good job of explaining it - which brings us back to your first post, unfortunately.

    Alasdair

    ps I looked up Doreen Tipton, perhaps I will need to spend a bit of time watching her on YouTube!
Reply
  • James,

    I am afraid I don't understand your point with this. The gravitational attraction between the sun and the earth acts (more or less, discounting tidal forces) equally on all of the earth. With your weights and string analogy the force acts at the point the string is attached to the weight. You then lose me with the "Any axis one chooses to define between these satellites". I am not an expert in celestial mechanics but I know enough to understand what is happening to the planets, though perhaps not enough to make a good job of explaining it - which brings us back to your first post, unfortunately.

    Alasdair

    ps I looked up Doreen Tipton, perhaps I will need to spend a bit of time watching her on YouTube!
Children
No Data