|Before you start......
||How are you doing?
*** If you do not wish to download
an "exec." file then you can copy and paste the "Listing"
into BB4W to run and subsequently edit it as detailed
This program can give really beautiful results - give it lots of opportunities (say 50!) to show what it can do. The stars are positioned randomly in three dimensions and given random initial speeds, Isaac Newton's Laws of Gravity and Motion are applied to the stars and their subsequent motions are shown, albeit in only two dimensions. You have to imagine the motions towards and away from you. To move onto a new start with a random number of stars, just press the Space Bar (that long thing on your keyboard). . Being able to do this sort of thing is why I enjoy programming. Being able to program sets you free from being bound to commercial products. Here's one I did recently (Here's its Listing )
NEW! Colour version
of Stardance with "step back in space and run again" facility
Coming shortly: 3d version (to be viewed through red/green
glasses) has already been written in QBASIC by a guest - shortly to
be translated back to BB4W!
For some superb java animations of double stars and related aspects of gravitation see the webpage from University of Tennessee, Knoxville.
Jupiter's Moons This program simulates the
apparent movements of the moons Io, Europa, Ganynede and Callisto about
the planet Jupiter as we look at their orbits edge on. These moons can
be seen as pinpricks of light close to the disc of
Jupiter using ordinary binoculars and the simulation
shows that what you will see will change from hour to
Ecliptic, Sun, Moon and Planets This program (listing) is able to show you (at each key press)
the positions of the sun, moon and the planets (mercury
to neptune) as they appear today in the zodiac, using ecliptic
coordinates. Just keep the space bar down for a few minutes
and you will see the fascinating looping motions of the planets
over the next few years together with the subtle regression
of the nodes of the moon which is the basis of the eclipse cycles.
When the program first starts you see the position of the sun for today (always on the ecliptic since this is defined as the path of the sun in the sky) and its ecliptic coordinates (alpha, beta) corresponding to ecliptic longitude and latitude. Note the aloha scale runs "backwards" (in the direction in which the celestial bodies seem to move from the earth's northern hemisphere). Also the constellation in which the sun is presently found is shown in abbreviated form. When you press any key (eg the Space Bar) the display shows similar information for the moon and subsequent presses show the positions of the planets today. If you keep the space bar down the display will show how all the bodies move in subsequent days and reveal the fascinating retrograde motions of the planets, which so baffled astronomers until they were explained by Johannes Kepler in 1609. Please note that the vertical scale is much exaggerated compared to the horizontal scale. (If you make an (enlarged) photocopy of pages 302-303 in Donald Menzel's excellent "Field Guide to the Stars and Planets (say at A3 size) you can join the strips to make a beautiful ecliptic diagram and see where the sun, moon and planets are in relation to the bright stars of the zodiac). This program uses procedures extracted from a full planetarium program written in BBC Basic which will appear on this site shortly (whose author generously donates it to us anonymously. He wrote it for the BBC Model B computer in the early 8Os starting from scratch using astronomy texts). I have used it with great joy ever since then - its predictions are spot on when you look out at the night sky.
Ecliptic View - Single Planet allows you to see just one planet - fascinating retrograde motions soon become apparent. Listing
Moon Phases shows how the moon wanes then waxes.
This program is a slight modification of one published in a book
called Quality Programs for the BBC Micro by the mysterious
Simon , a lecturer in computing science at Exeter University.
When I first saw this program run, I realised that what we see over
a month (clouds permitting) of the moon is representable by a hollow
hemisphere, painted white on the outside and black on the inside, rotated
about the axis through its poles. Listing
Slug - not for the squeamish! This program was
developed with the help of school pupils in a Computer
Club. Leave it to run for a few minutes (or hours) while
you go and do something else.(Or just minimise the Slug.exe
window and come back to it later to see how our little friend
is getting on). The slug does a "random walk" (or in this case
a slither), the subject of one of Albert Einstein's first scientific
investigations.The program which makes this happen is very short.
Here is its Listing - or set of computer
instructions - which in this case creates the impression
of our slug and its trail of .............
Slugchase uses Richard Russell's Menu Program to generate coloured versions of the above. Listing
Red v Green - Here you can (pretend to?) test
your will-power against that of the computer...Give the program lots of
goes with different sized grids. This sort of scenario has been called the
"Game of Life". The red organisms struggle against the green ones. Their
world is really like the surface of a sphere - the top of the screen
wraps round to the bottom and the left of the screen to the right, as
did the world of the slug above.Click on Listing
to see how it works.
Reminder Timer - turn up the sound and this will help you remember to do that vital...... what was it? I wrote this recently. Its quite fun - shattering if the volume's turned up on your soundblasters Listing
Dayfinder You input your birthday and it works out
which day of the week you were born.
Don't forget .....
Monday's child is fair of face,
Tuesday's child is full of grace,
Wednesday's child is full of woe,
Thursday's child has far to go.
Friday's child is loving and giving,
Saturday's child works hard for a living,
But the child born on the Sabbath Day,
Is bonny and blithe and good and gay.
Date of Easter contains a cunning algorithm which
enables you to find the date of Easter up to 2099.
Easter Day occurs on the first Sunday after the full moon
which occurs after the Spring Equinox.
in 2003 the equinox occurs at 0100UTC on 21st March; the full moon has just
occurred on the 18th March and the next full moon is on 16th April,
a Wednesday; so that Easter Day is on the following Sunday, 20th April.
Lunar Lander - the classic game ( Listing ) provided by another enthusiast
for BBC Basic, Zyra .
Can you land and stay in one piece?
HOW ARE YOU DOING?
Running Averager useful to see how you're
marks are stacking up at school. Useful for teachers
Teacher's Pet calculates percentage marks from
any total mark e.g. in a test. Listing
Factors will find the prime factors of numbers up
to 999999999. Listing
Throw 3 dice 5000 times and see the results
tabled and graphed in a trice. Listing
Circles in BBC Basic has its own page
Ellipses in BBC Basic has its own
Kepler's Elliptical Orbits has its own
page for science and maybe even art
Spirals in BBC Basic has its own page
Lissajous Figures - originally produced by
Jules Antoine Lissajous (1822-1880) using tuning forks, mirrors and light
beams - now more often demonstrated with an oscilloscope. Listing
are calculated in Chemistry. Listing
Gas Chromatogram Simulation - the analytical
method to separate gases and volatile liquids. Listing
Adding Machine- really useful and easy to see. I've used this for years - very simple but just what I need every few days. Now, thanks to Richard Russell, I can use it on my PC as well as on my "old" Acorn Archimedes, dating back to 1990. My first computer was the BBC Model B purchased in 1983.Listing
Direct Debit Manager Keeps your finances out of the red.
Enjoy! And please feel welcome to contact me at firstname.lastname@example.org
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