Science Aplets
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Most of the aplets and programs listed here were written for the HP38G. I am a maths teacher not a science teacher and I have not been able to trial them. After ten years I have never once had a single email giving feedback on them so I am very reluctant to invest any more time in them.  Hence I am not going to update them to the new datalogger aplet, nor am I going to spend time trying to convert them into 39G aplets. If any reader is interested then contact me.

Note: See the Pendragon Files for some small programs that may be of interest to Science students.  There are versions of these for the HP38G & HP39G. See also the Misc Aplets page for other material that may be of use.

E-Mail any feedback to me:   EMAIL ME

    Datalogger software and resources
  A new version of the datalogger has been produced by Firmware. If you have bought it and would like to download the aplets for it (38G or 39G), the documentation, and some example activities, then see right.  I believe there is also a companion program for the PC which will manipulate the data once transferred to the computer. See Firmware's homepage for this.
Please note: I have no plans to update the aplets listed below to use the new version. See my note above.
bulletDownload the old 38G Datalogger aplet 
bulletDownload the new 38G Datalogger aplet
bulletSee the manual for the 38G aplet (PDF)
bulletDownload the new 39G Datalogger aplet
bulletSee a collection of activities (PDF)
bulletSee suggested experiments (PDF)
    Chem Lab 39
  ChemLab39 is a work in progress for the 39g+. It will run on the older 39G, but will be very slow. It is a stand-alone library at the moment with one command "PT". I will make it better (like always) when I have more time. I wrote it in a little under 8 hours of work so don't expect too much! ;-) Read the readme file for info about what the numbers on the screen mean and how to calculate molecular weight of chemicals.
Note from Colin Croft: Don't believe him! Tim's 8 hours is VERY good and well worth a look! You have to use the RECV/"(Wire)" command to download it from the PC and when you do it will seem that nothing has happened. Just type PT in HOME to activate it.

Author: Tim Wessman

    Ionic Solubility
  This is a program not an aplet and must be downloaded into the Program Catalog.  If you give it the component parts of a reaction (cations and anions) then it will give you precipitates and colours. As referenced in "A Student Revision Handbook CONCISE TEE CHEMISTRY" (1st ed), Lucarelli, Nick., Lucas Publication, pg 5.  The loading time for this when you run it is about 1 minute so you'd need to do something else when using it. 
Note from Colin Croft: My Yr 12 students who also do Chemistry tell me that they'd probably just use the written version in the table book but that it might be useful for students who found this topic difficult.

Author: Jonathan Wan

    Chem Ions
  This is a program not an aplet and must be downloaded into the Program Catalog.  It has around 51 ions stored with their names and charges. To use it, all you have to do is type the first 2 letters of the ion you're looking for using the ALPHA button. The programme then displays all you need to know about the ion in a message box. If there's more than one ion with the first 2 letters you've typed, the programme asks you to choose from a list of ions beginning with the same two letters you've given it. A lengthy help file is included for anyone having trouble with it.  It's about 16 kb at full size and runs only on a 39g. The author says "I could make it work on a 38g but it would need to be split into several files. I'll do that if people using a 38 g really need chem ions to work on their calculators."
Note: This program takes a while to compile the first time you run it.

Author: Jarryd Pinto

  Library L1542 (Version 1)
Released 8th July, 2003. This is an upgrade to the L1540 Library which also incorporates string handling. You need this if you're a serious programmer!!
Note: The included documentation is good but terse. I will be providing more detailed documentation when I have time. Check back later.

L1542 is a 33KB SysRPL library for the HP39/40. When you download it to your calculator this library gives access to an add-on collection of extra functions which then become available in HOME, in programs or in the CAS (on an HP40G). The functions essentially comprise much of what makes the difference between an HP40 and an HP49, plus some more.

Functions added include a decimal/hex conversions, a calendar, a list of metric/imperial conversions, a list of physical constants, some time/value/money functions similar to those on the TI89, probability functions, vector plot and matrix slope plot, multidimensional optimisation, discrete Fourier transforms and numerical solution of differential equations. Even a help command is included which explains how to use each function!

For programmers there are REALLY useful functions that let you do bit manipulations, perform graphic plots, call programs in nifty ways as functions (ie. returning values), use local variables instead of the global ones A..Z and, most importantly, input, manipulate and output string variables. String constants can also be realized with the aid of an additional tiny library L1840, which is included in this package.


This library even has a command to delete itself so that you don't have to reset your calculator (losing not only the library but everything else as well).

The source is included and compiles with the HP DOS tools.

Author: Martin Lang (Germany), with contributions from Jordi Hidalgo.


  Is the temperature at which water freezes, descending from above, the same as the temperature at which it melts, ascending from below?  This aplet lets the student collect data with which to answer this question?  Requires a temperature probe.

Author: Colin Croft

    Gas Laws 1
  This aplet lets the student collect data with which to investigate the gas law relating the pressure on a gas to it's volume.  Requires a pressure probe.

Author: Colin Croft

    Gas Laws 2
  This aplet lets the student collect data with which to investigate the gas law relating the temperature of a gas to it's volume.  Requires pressure and temperature probes.

Author: Colin Croft

    Food Energy
  This aplet lets the student collect data with which to investigate the energy content of food in calories.  Requires a Celcius temperature probe.

Author: Colin Croft

  This aplet lets the student collect data with which to investigate the effect of gravity on the vertical position and velocity of a falling object.  Requires a distance (sonic) probe.

Author: Colin Croft

Last modified: 19 Dec 2007                                             Sitemap        Home        Contact Me