Ejs open source Vernier calipers java applet with objects, help & 0-error logic

[dipu222]

Dear Lookang,
Can You add another version 0.1 mm Vernier constant where 10 divisions of vernier will coincide will 9 divisions of the main scale. Which will be very useful for me because I am using that in the class. Thanking you.

[lookang]

Hi dipu222
I dont understand what u mean
Do u have a picture to explain ?

ok i understand what u mean now after looking at my own applet version 3

but it would make the applet vernier scale very short in the x direction, see attached image.
u sure it is what you want?

[Fu-Kwun Hwang]

Dear Lookang,
Can You add another version 0.1 mm Vernier constant where 10 divisions of vernier will coincide will 9 divisions of the main scale. Which will be very useful for me because I am using that in the class. Thanking you.

Are you looking for something like Vernier or Another Cliper?

[lookang]

Dear Lookang,
Can You add another version 0.1 mm Vernier constant where 10 divisions of vernier will coincide will 9 divisions of the main scale. Which will be very useful for me because I am using that in the class. Thanking you.

done!
enjoy! under 0.1 mm version 4 option of drop down menu!
please thank Professor Fu-Kwun Hwang too, he is the one who created the original versions http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=567.0 & http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=1189.0 so that people like me (ordinary teacher) can make this version http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=684.0 even more customized to our own pedagogy hints and design features.

[lookang]

21 july 2011
added zoom for close up view of the vernier scale on the main scale


some teacher feedback that in secondary 1 and 2 (grade 7 & 8 ) the students are expected to answer in cm.
i may have to create cm drop-down options/version as well ?!!?.

i suggested that to teach 10mm = 1.0 cm would have been an easier way and to prepare students for real world, mm should be explained instead of the cm answers.

It is rather painful to add cm to all the possibilities of the simulation now that it is rather complex, with hints and answers all in mm

how?

[Fu-Kwun Hwang]

I would suggest to keep original display: i.e. in unit of mm.
As far as I know, mm is the unit being in work place (for technician who use calipers).

And it is not difficult for student's to convert between mm and cm.

[lookang]

I would suggest to keep original display: i.e. in unit of mm.
As far as I know, mm is the unit being in work place (for technician who use calipers).

And it is not difficult for student's to convert between mm and cm.

thank you for your confirmation, i will not re-create a cm version

27july 2011
fixed bug where 0.02mm is selected the hints is 11.98 mm is shown as 12.00 + .98 mm the top pointer jump ahead due to a code

Code:

if(unit==0.02)out=((int)(v*50+dv))/50.;

the correct code is inserted as

Code:

if(unit==0.02)out=((int)(v*50.+dv))/50.; //// 50. instead of 50 fix bug of pointer

[lookang]

31 october 2011
redo the zoom into a similar magnify just like the micrometer thanks to ability to draw students attention to the lines based on codes from http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=2268.0 by Fu-Kwun Hwang
randomize the size of the black object each time to simulation is reset for greater challenge and fun

enjoy!

[lookang]

planning a lesson on Googlesite https://sites.google.com/site/lookang/ with National Junior College teacher.

Code:

[applet code='users.sgeducation.lookang.AAPTVernierCaliper_pkg.AAPTVernierCaliperApplet.class' codebase='https://sites.google.com/site/lookang/Home/ejs_AAPTVernierCaliper.jar?attredirects=0&d=1' archive='ejs_AAPTVernierCaliper.jar' name='AAPTVernierCaliper2452' id='AAPTVernierCaliper2452' width='750' height='520' mayscript=true>

[lookang]

edited the applet to show actual reading = main scale + vernier scale - (zero error)
enjoy!
writing a journal article on this


contributed this to Wikipedia a while back and it is still there! http://en.wikipedia.org/wiki/Caliper
Zero error

The method to use a vernier scale or caliper with zero error is to use the formula 'actual reading = main scale + vernier scale - (zero error)'. Zero error may arise due to knocks that cause the calibration at the 0.00 mm when the jaws are perfectly closed or just touching each other.
when the jaws are closed and if the reading is 0.10mm, the zero error is referred to as +0.10mm.The method to use a vernier scale or caliper with zero error is to use the formula 'actual reading = main scale + vernier scale - (zero error)' thus the actual reading is 19.00 + 0.54 - (0.10) = 19.44 mm

Positive zero error refers to the fact that when the jaws of the vernier caliper are just closed, the reading is a positive reading away from the actual reading of 0.00mm. If the reading is 0.10mm, the zero error is referred to as +0.10mm.
when the jaws are closed and if the reading is -0.08mm, the zero error is referred to as -0.08mm..The method to use a vernier scale or caliper with zero error is to use the formula 'actual reading = main scale + vernier scale - (zero error)' thus the actual reading is 19.00 + 0.36 - (-0.08) = 19.44 mm

Negative zero error refers to the fact that when the jaws of the vernier caliper are just closed, the reading is a negative reading away from the actual reading of 0.00mm. If the reading is -0.08mm, the zero error is referred to as -0.08mm.

[lookang]

changes:
2) Corrected the Java simulation to allow units (or to ask for the answer in mm) and to prevent the vernier scale from being unreadable.

done.
added mm in texts
made xmagnify = -10 , ymagnify = 0
found that mx and my is causing the weird behavior, made them -10 and 0 as well like xmagnify and ymagnify so that it loads at the centre of the simulation view!

the simulation is downloadable from the this post or
mirror here
http://dl.dropbox.com/u/44365627/lookangEJSworkspace/export/ejs_AAPTVernierCaliper.jar

enjoy!