What language/tools should I learn and use?
I'm almost completely new to programming (I've only made rudimentary maths programs in Python) so I would like to approach learning to program properly. In order to get proper advice, you need to know what I want to create.
Essentially it is a physics program that shows the decay chains and ratios of radioactive isotopes and their products. For example, the user selects Carbon-14 and a suitable time frame, presses go and sees the ratios of C-14 and its products change over time. What I would like for the output is a table of values, a couple of pie charts and the option to pause, play and stop the model.
The main meat of the program is the calculation. This should be relatively easy as it's simple number crunching (I could do that in Python now). What I need advice on is how to go about creating a user input (list of isotopes, chosen mass/number of atoms, time step, etc.), having that feed into the program, and having the resulting information being fed out and constantly updated in the form of pie charts/ tables.
I only have about 3 weeks (3-4 hours a day-ish) to go from nothing to finished working product. Visually, the final program needs to be functional above beautiful. I don't mind it looking a bit windows 95 (but it would be nice if it could be refined if I have time).
So, what programming language/software should I use? What additional stuff do I need for the input/output? How long do you think it will take?
Well, for starters, you could use a spreadsheet program.
Based on my understanding of your physics problem, a spreadsheet program would suffice. At most, you might need to need to learn a couple of statements of the macro language that the spreadsheet program uses. Any good spreadsheet program would have the number crunching ability you're looking for, and features to display data in the form of graphical charts.
Using a spreadsheet program would be simpler given the time frame you have and the nature of problem at hand; and you can focus on the physics problem, rather than bother about the myriads of libraries and API's that you would have to study to build a graphical application.
(FYI, if you're still interested in programming it yourself, then take a look at python's pylab library)