GeoGebra

Micrometer Screw Gauge – Self-Practice GeoGebra Applet

After completing the vernier calipers applet, I simply had to do a similar one for the micrometer. However, this was a lot more complex as the thimble’s numbers are supposed to be “rotating” rather than moving linearly. A lateral movement of the thimble had to be coupled with a vertical movement of the rotating scale, with the corresponding numbers on the scale constantly changing with each new problem.

Students will need to make readings when the spindle is closed and when open to measure an object before subtracting the zero error and keying in the answer for the actual measurement. The answer will be checked for accuracy, although not for the correct number of decimal places because I have not figured out a way to programme that check yet.

To access the applet in fullscreen, go to https://www.geogebra.org/m/qedrwymk. To embed into SLS, you may use this code:

<iframe scrolling="no" title="Micrometer with zero error" src="https://www.geogebra.org/material/iframe/id/qedrwymk/width/640/height/480/border/888888/sfsb/true/smb/false/stb/false/stbh/false/ai/false/asb/false/sri/false/rc/false/ld/false/sdz/false/ctl/false" width="640px" height="480px" style="border:0px;"> </iframe>

Vernier Calipers – Self-Practice GeoGebra Applet

The aim of this applet is to help students who just learnt about zero errors in vernier calipers to get some practice of their own. Students just have to key in their answer into the textbox and they will know if they got it correct.

To modify later: an option to give the correct answer if the student asks for it.

I have not figured out how to ensure that the input is expressed in 2 decimal places, so if any expert is able to advise, I will be glad to try it out.

To access the applet in fullscreen, go to https://www.geogebra.org/m/jybrnwgp. Meanwhile, the applet is embeddable in SLS using the following iframe code.

<iframe scrolling="no" title="Vernier calipers with zero error" src="https://www.geogebra.org/material/iframe/id/jybrnwgp/width/640/height/480/border/888888/sfsb/true/smb/false/stb/false/stbh/false/ai/false/asb/false/sri/false/rc/false/ld/false/sdz/false/ctl/false" width="640px" height="480px" style="border:0px;"> </iframe>

Credits to Abdul Latiff for the original applet which I modified to add the zero error readings.

UX design considerations for GeoGebra apps

Having started with making interactive simulations or visualisation apps with Easy JavaScript Simulations (EJsS) under the guidance of Senior Specialist Lawrence Wee from ETD in Nov 2016, I next learnt about GeoGebra in 2017 from my ETD colleagues who taught Math (shoutout to Loh Yan Xiang and Toh Wee Teck). I would like to share via this post a few guidelines that I have come up with when designing interactive apps for students

1. Fast and Minimalist Designs

Since picking up the necessary skills, I have been generating a number of interactives during my free time in preparation for my eventual return to teaching after my stint in ETD from Jun 2017 to Dec 2019. I continued to do so, often in tandem with the upcoming topics that I need to teach for JC1 and IP3 Physics – mainly Mechanics topics.

To balance creation of apps with fulfilling all my other duties, I needed to produce them in a minimalist and very targeted just-in-time manner. Working off templates help a lot as I do not have to redesign the buttons or re-code the animations triggered by the buttons. There is no need to spend one whole day working on an app to beautify it if all it needs to do is to demonstrate the motion of an object based on its acceleration-time graph, for instance.

2. Start with the Minimum Viable Product.

Most of the time, I need to go off to class with a minimum viable product (MVP) in software development speak – a workable no-frills version of the interactive that communicates the ideas or allows the visualisation that I intended. This will then allow me to receive quick feedback from my students on what works and what does not. I will then be able to make quick changes before the next class or in preparation for the next cycle of teaching.

3. Avoid Overloading Interactive Elements

I am a strong believer in displaying just enough buttons and sliders to do the trick. Each app should not have more than 3-4 interactive elements to avoid distracting the students from the main relationships or interactions that they need to learn.

The use of GeoGebra allows for me to make quick clones of an app and then modify it quickly to generate a new scenario, instead of adding more interactive elements to allow for multiple scenarios within a single app.

I also try to avoid giving too much information on the app itself, as I feel the content delivery should be done outside of the app, whether via the Student Learning Space, Google Classroom or even face-to-face classroom interactions.

4. Optimising for Small Screens

I try to keep to an app size of 640 px wide by 480 px height so as to optimise the app for the Student Learning Space. These dimensions also make it easy for students to view and interact with the app from their mobile phones, even when held in portrait mode.

5. Use Pastel Colours

Instead of using the traditional bold primary colours, I try to use pastel colours or more “soothing” colours to highlight key information or elements. These are the softer versions of the primary colours and I prefer to use them as it gives the key elements a pleasant accent despite the rest of the app being mainly grey, black and white.

Harmonics of Open and Closed Pipes

The following GeoGebra interactives demonstrate the first few harmonics of an open pipe and a closed pipe given a fixed velocity of sound (340m/s). The frequencies and wavelengths are auto-calculated. Length of the pipe can be varied. Feel free to use, copy or edit them.

Open Pipe

Source: https://www.geogebra.org/m/tsufws72

For embedding into SLS or other websites:

<iframe scrolling="no" title="Harmonics of Open Pipes" src="https://www.geogebra.org/material/iframe/id/tmeypwgx/width/700/height/500/border/888888/sfsb/true/smb/false/stb/false/stbh/false/ai/false/asb/false/sri/false/rc/false/ld/false/sdz/false/ctl/false" width="700px" height="500px" style="border:0px;"> </iframe>

Closed Pipe

Source: https://www.geogebra.org/m/m3p7hny5

For embedding into SLS or other websites:

<iframe scrolling="no" title="Harmonics for Closed Pipe" src="https://www.geogebra.org/material/iframe/id/gm9k6hkg/width/700/height/500/border/888888/sfsb/true/smb/false/stb/false/stbh/false/ai/false/asb/false/sri/false/rc/false/ld/false/sdz/false/ctl/false" width="700px" height="500px" style="border:0px;"> </iframe>

Equilibrium of a Wall Shelf

This GeoGebra interactive allows students to vary the position of the centre of gravity of a shelf in order to observe the changes of the other two force vectors. The position of the supporting cable can be adjusted too.

The ability to resolve vectors allows students to apply principle of moments to understand how the vertical components of each force vary.

This is meant for the JC1 topic of Forces.

To embed into SLS, you can use the following code:

<iframe scrolling="no" title="Equilibrium of a Wall Shelf" src="https://www.geogebra.org/material/iframe/id/xdbr7qr5/width/700/height/500/border/888888/sfsb/true/smb/false/stb/false/stbh/false/ai/false/asb/false/sri/false/rc/false/ld/false/sdz/false/ctl/false" width="700px" height="500px" style="border:0px;"> </iframe>