Flashscience.com - blog

 
December 16
So, I've really slowed down on the site this year. There are a number of reasons, but I'm just making excuses. I have, however, embarked on the project of making all of the source code available for users to do what they want & making windows or mac projectors of the learning objects available for off-line use.

 

November 26 2009 - STAVCON 2009.
I'm presenting at the Science Teachers Conference on the teaching of electricity. Here are the documents if anyone is interested:
Teaching electricity presentation
Using multimeters
Year 8 prac notes , answers
Year 10 prac notes , answers
Electrical engineering workbook

 

November 3 2009 - A few random things...
It's been a very slow year for me, so this is a bit of an apology & an explanation. So why so little new content this year? Well.... firstly there are always lots of things to do in life that are actually more important than spending many hours working on fiddly flash things. Second, it seems that most of the ideas that I've had for useful, original learning objects I've now completed or in the time that I've been working on this project someone else has done (& usually better than me too). So with some holiday time coming soon, I'll try to finish off a couple of unfinished projects & evaluate anything that needs improvement for next year.

 

July 14 2009 - The forum.
To keep up with the spirit of "Web 2.0" , Flashscience now has a forum. I'm hoping to get some good feedback and ideas from users, so please be sure to register and use this feature.

 

June 26 2009 - DC motor animation.
Now that Unit 4 Physics is underway, we've been looking at DC motors. I have constructed an animation that shows the relationship between current, magnetic field & rotation. It's currently a bit primitive, but a few options will be added in future.

 

April 24 2009 - I've finally finished a project that has been sitting around for more than twelve months!
The reaction time learning objects allows a user to test their reaction times for visual or audio cues. I am also working on implementing a random generator that changes the size and shape of the cat, as well as randomly changing from the sight test to the sound test. Nothing revolutionary here, but a nice simple (& fun) test.

 

March 23 2009 - Rectifier smoothing (again!)
I have made some major changes to the rectifier smoothing learning object. The previous full-wave rectifier animation has been incorporated into it & output graphs for full wave rectification are now possible. Also, the method used to calculate DC voltages for un smoothed output has been changed to the averaging process as used in smoothing, rather than the approximation equation. A lot of behind the scenes work, but very worthwhile.

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February 15 2009 - STAV Physics Teachers Conference
Today I am presenting at the STAV Physics Teachers Conference, on the topic of the Virtual Lab. Here is a pdf copy of the keynote presentation.

 

January 5 2009 - Transistors & amplifiers
I know that there are a number of projects that have stalled, but I have been busy updating the previous amplifier learning object to incorporate information about how a transistor works & the basics of an amplifier - in particular gain & clipping as these are relevant concepts for the VCE study design.

 

November 8 2008 - Kirchhoff's law learning object.
Still haven't finished the last few projects, but I'm working on yet another. (I promise to finish a few soon once school starts to wind up at the end of the year.) I have started work on a tutorial about Kirchhoff's laws. At the moment all that is on the site is the circuit. It works pretty well - you can play with the values for voltage & resistance & see the effects. The final product will contain a few slides of information, plus the ability to reverse voltages on the batteries.

 

October 3 2008 - Projectile motion learning object.
I know that there is a lot of stuff out there on this, but most of the applets that I've seen on projectile motion just show the path rather than explaining the concepts. At the moment, it's a bit rough. I've been working on a few other projects, so this one has been on the back-burner for a few months. I hope to put a bit more information about the vector nature of the moving projectile.

 

6 September 2008 - Chemical reactions learning object
Trying to explain the concept of balancing chemical equations to a class, so what better way that to make a flash animation? It's not quite ready yet (the class will be finished the topic long before I finish it), but I've made a start.

 

13 August 2008 - A few fixes
Now both measurements on the rectifier smoothing are updated in real-time was the values for R, C or V are changed.
I've also fixed up a few font issues in the maths quizzes - based on the Comic Sans font rather than the less common Chalkboard.

 

8 July 2008 - Presentation to the Adobe User Group.
On Monday July 21, I will be be speaking to the Melbourne Adobe Users Group about the flashscience project & the use of learning objects in the classroom. I have posted a flash file here of my presentation.

 

4 July 2008 - Titration learning object.
Not quite finished yet. I've actually had this one sitting 90% done for a while - now I'm up to 95%. I just need to set it up to change the starting volumes & include a slight change in the pH calculation for weak acids.

 

2 July 2008 - The radioactive decay object is finished and published.
This one took about a week to make - there's nothing that difficult in it. I like the fact that users can toggle between the graph, table & count. It also highlights the properties of exponential decays quite well.
The time constant for the decay is a bit of a weird one - 0.69 minutes (the natural log of 2). Makes sense only because the rate & amount are equal to each other, but I think that an integer time constant might make calculating & visualising a bit easier. I did this only because at my school we use the IEC Magic Source simulations that use this time constant - this applet was designed to complement the classroom activity. Of course, as these things cost about $200 each, I feel obliged not to make them redundant (yet).

 

15 June - Diode IV characteristics is finished & published.
This learning object was designed to replace a fairly complicated circuit that was used to record data for VCE unit 3 students. The aim is to show the characteristics of the diode with very low currents running through, as well as the knee & forward bias on voltage. I have deliberately kept it as simple as possible by showing a constant on voltage above a threshold current - not quite ideal but this is how it is depicted in the VCE texts and exams.
It also shows a visual depiction of light emitted by an LED as current increases. Kind of interesting - the LED doesn't need much current through it to reach what our eyes perceive as full brightness.

 

May 24 - Rectifier smoothing is finished & published.
Now that I have finished teaching further electronics, I've put together a simulation of rectification & capacitor smoothing for use next year. I think that this is the best of its type that I have seen :) This is probably the most interesting piece of maths I've used in a script too. To produce a combination of a sine wave as the input voltage rises, with an exponential decay as the input falls was tricky. This needs to also include the fact that the changing frequency changes the time over which this all happens. Here is the fun part:

for (i=0; i<=400; i++) {

xSmooth = i;
xTop = i;

ySmooth = -(40/3)*((1.41*voltIn)-0.7)*Math.exp((-(i-(Math.floor((i-(0.25*8000*period))/(period*8000))+0.25)*period*8000))/(res*cap*8000));
yRect = -1*((40/3)*(1.41*voltIn)*Math.sin(6.294*i*frequency/8000))+(0.7*40/3);

if (yRect < ySmooth) {
yTop = yRect;
}

else {
yTop = ySmooth;
}

There is one hiccup though - the DC voltage out calculation doesn't calculate in realtime, but only on release. Not sure how to fix it at the moment. That's a job for the future. I also plan on combining this with the current fullwave rectifier object.

 

1 April 2008 - Welcome to the Flashscience blog.
What a great date to start this! Here you'll find a few ramblings by me (Justin) about this project - news, future directions & notes about the content. I can't guarantee that it will be an interesting read, but you never know!