Re: Dynamic 2D plotting in V6

• To: mathgroup at smc.vnet.net
• Subject: [mg77261] Re: Dynamic 2D plotting in V6
• From: dh <dh at metrohm.ch>
• Date: Wed, 6 Jun 2007 07:01:58 -0400 (EDT)
• References: <f43gvd\$2s2\$1@smc.vnet.net>

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Hi Todd,

give the slider an exponential behaviour, e.g.:

test2={Slider[Dynamic[hh],{10^-10,1}],

Dynamic[Plot[-Log[10,h],{h,1/10^14,Exp[10 hh]/Exp[10]},PlotRange->{0,14}]]}

hope this helps, Daniel

Todd Allen wrote:

> Hello All,

>

>    First, let me congratulate WRI on the release of

> Version 6....I think many of us are finding "golden

> nuggets" that make this a very fun release to have in

> our hands.

>

>    I'm an educator and have always been interested in

> finding a way to explain the concept of pH (defined as

> the free concentration of hydrogen ions in a solution)

> to my biology students.  Plotting pH graphically has

> always been out of the question because of the

> tremendous range of values that pH relies upon (from

> 1*10^-14 to 1).  When I saw that Version 6 has dynamic

> updating ability, I became excited with the

> possibility that V6 might dynamically update one or

> both axes on a graph and finally make it possible to

> show students how pH changes as you vary the hydrogen

> ion concentration.

>

>    If you have V6, please copy-paste the following

> short code and you can see how the slider bar does

> change the x-axis (in this case the hydrogen ion

> concentration) dynamically.

>

> Code:

>

> test2 = {Slider[Dynamic[h]],

>   Dynamic[Plot[-Log[10, h], {h, 1/10^14, 1},

>     PlotRange -> {{0, h}, {0, 14}}]]}

>

>

> The problem is that most of the interesting change in

> the pH value is "compressed" along the leftmost side

> of the slider so that the smooth, gradual increase in

> pH (as hydrogen levels drop) is not well illustrated.

> The graph itself looks "tied" to a pH value of 8, when

> at very low hydrogen concentrations there should be a

> nice gradual curve towards a pH of 14.

>

> Would anyone have any ideas how to solve this

> compression issue and make the graph more illustrative

> to students?

>

> Happy computing!

> Todd

>

>

>

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