Virtual vs Tangible Labs

At this moment, the AP Chemistry exam is in 19 days. I have about 1.5 chapters to cover with class only 3 times per week.

I was at this same point last year, but the exam was a week later, so the situation wasn’t as stressful as it is this year. But, that’s the nature of the exam and I have to work with it.

Currently, we’re discussing applications of aqueous equilibrium…specifically, titrations. This is one of the great topics for labs, but how does a time-strapped teacher work an entire titration into one class period? I feel like a lot of teachers at this point would just skip it and do what they could to get all of the content in.

Because there are so many people on the internet much smarter than me, I was able to find two fantastic titration simulations. You can see them here and here.

The first is a good introduction. I had students use it for a strong acid – strong base titration to get the idea down.  Students can select the type of reaction, which to titrate (acid or base) and what chemicals to use.  They then run the titration and calculate the molarity of the chemical in the buret and check to see if their answer is correct.  The mechanics of the simulation are the same as an actual titration and they can get instant feedback from me as I wander the room and from the web when they check their answer.

The second simulation is more in depth (designed by a college Ph.D) and is more skill-based than the initial titration they ran. There are more variables and require the student to really understand what is happening in the chemical reaction.  I really like the real-time pH curve that is displayed for the students and the instant feedback the simulation gives.  This particular site also has 3 different experiments students can choose from…acetic acid titration, unknown weak acid titration, and determining pKa of an unknown solution.

If you’re running out of time, don’t be afraid of virtual labs. My kids have now done 4 different titrations and I didn’t “lose” any class time. This is the Google Doc procedure my students used today if you’d like to use it.

Another great simulation resource is the University of Colorado, Boulder physics department website sims made for chemistry, biology, physics, and math.

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Update 4/2/2012: After receiving some questions about my procedure and the websites, I am sad to report that the second titration simulation from the University of Pasadena is no longer available. Also, I have accidentally lost the Google Document procedure I linked in the original article. If you find other titrations that work well for you, I would love to hear about them in the comments.

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