Monday, April 24, 2017

SearchResearch Challenge CONTINUED! (Can you build an interactive widget for the island viewing problem?

Let's work on this a bit longer... 

Remember that the SearchResearch Challenge this week is to figure out how to make an interactive widget that can interactively show the relationship between height and visible distance in the "island viewing" problem.  That is:  

1.  Can you make an interactive widget that illustrates "how far out to sea can you see" without going into full-developer mode and writing a bunch of HTML, CSS, and Javascript?  

The comments from the last week have been pretty helpful, but nobody's got a solution yet.  It's possible that there isn't a good solution (that is, without going fully into HTML/Javascript), but we're tantalizingly close!  

One thing I found that helped was to use somewhat different search terms.  

I found a lot of interesting tools by searching like this: 

     [ interactive animation tools ] 


     [ interactive tool for physics animations ] 

How did I come up with these search terms?  Easy.  I just described what I was looking for to a friend.  As I "translated" what was in the SRS post into everyday speech, I realized that I wasn't searching for a way to "build a widget," but I was looking to find a way to build an interactive animation.  

You know, it's funny to think about this because... once upon a time... this was simple to do in Apple's now-defunct scripting tool, Hypercard.  (Here's a longish demo of Hypercard.)  Of course, this was in pre-WWW days, but thousands of teachers were able to easily create content -- including interactive animations to illustrate physics.  

In any case, let's keep on this task for the rest of this week.  

I'll pop back in on Wednesday with an update on how I'm doing.  

Keep searching!  



I'm repeating the statement of what the widget should look like below... 

To get you started, here's a side-by-side sketch of what such a widget might look like.  In the first image, the observer's eye is 1.7 meters above the beach, which lets the observer see 4.7 km out to the visible horizon.  

The interaction is simple:  As you drag the red dot up, the value of the "height above the beach" changes.  In this image, it's 100m.  You can drag it down to 0, or up to a much higher number.   As you drag, the widget updates the "visible distance" number as you drag, and redraws the red line to touch a point on the circle (in this case, one that is 36 km out). 

In this next image, I've dragged it down a bit.  Here it's just 1.7 meters above the beach, and the red dotted line only goes out 4.7 km. As I drag the dot, the numbers should update, the line to the dot should move up and down, and the line to the point on the circumference of the circle should slide along to show the distance.  

NOTE:  These are sketches of what the widget might look like. They're NOT images from a working widget.  

The formula connecting these two variables look like this: 

     distance = 3.7 * (height ^ 0.5)  

where height is in meters, and distance is in kilometers.  (In the top example, since the height is 100m, the  square root of 100 is 10. Hence,  10 * 3.7 = 37 km.)  


  1. Hello Dr. Russell.

    I tried with your new input modifying the words.

    Until finally tried [interactive tool horizon distance calculator]

    Horizon Finder on Google Maps" This tool can be used to see the area covered by the visible horizon from a given location. As the height of the base point is changed, the visible horizon will change to suit. You can either specify a height manually or let this tool estimate the height and produce the visible horizon polygon automatically."

    Horizon calculator - radar / visual

    I will keep searching

  2. Hi Dan,

    Here's a solution (to be perfected) using Geogebra, a soft used for mathematics in highschool. I knew it before but never used the scripting possibilities to make interactive applets. You can find it searching for [interactive maths software], it comes first on the SERP. I think looking for a maths interactive soft is more clever, physics softs are usually quite messy (unless you exactly know which part of physics you want to illustrate) and the problem you submitted is more a simple maths one (tangent to a circle) than a physics one.

    The applet is here :


  3. looked at the approach of solving geometric equations online (mention of teachers triggered this thought) - after a couple of searches settled on *geometry + online + tools* , from the list selected

    its easy to input a semicircle, then draw an intersect to the semicircle and tangent from the intersect, define the equation of the tangent 3.7 (h ^0.5)

    move top point of the intersecting line to display values of the tangent in the left panel.


  4. Lela seems to have found a tool to make an interactive slider… her quote: (see her comment 4/19/17)
    "Found by searching "Distance to horizon slider" and clicking through via a blog debunking flat-earthism!" Lela
    playing with the example Lela provided on GeoGebra:
    trying the Farallones [not correct, but did manage to input an image]
    using Ramón's find plugging in values…
    not as fun as a slider, but would bring them into view under the right conditions
    the problem I ran into with the GeoGebra tool was how small the distances were to make the model/slider work…
    Mick West was cited in the GeoGebra example