Tuesday, 23 November 2010

Not as easy as it looks

We've just posted a new video in which two Coke cans are dissolved in acid and base.

We used hydrochloric acid and sodium hydroxide. The results were impressive.



However making this video was not straightforward.

Originally the idea was to dissolve two different aluminum cans - Coke and Pepsi.

We thought it would be visually striking because red (Coke can) is traditionally associated with acid and blue (Pepsi can) with base.

However an initial test run resulted in virtually no reaction.

We quickly realised this was because the cans were covered with a protective coating, inside and out.

Lab technician Neil Barnes sand-blasted the coating from the inside of the can (it took two attempts to remove it).

The cans then sat on the shelf for a couple of weeks while we made other videos.

Then we noticed another problem.

Just before filming, Dr Sam Tang noticed the sanded Pepsi can had rusted slightly!

This should not have happened to aluminium.

A quick check with a magnet showed the Pepsi can was not aluminum but steel... A fact we then noticed was written on the can itself!

So the Pepsi cans were put to one side, and the whole experiment was done only with aluminium Coke cans.

Below is an extra video we've created showing it in real-time with less editing.

2 comments:

  1. Nice demonstration. I have seen a lot of the Periodic Videos and I'm wondering why you only use the "popular names" for substances and rarely the formulas.
    I'd love to see HCl and NaOH next to "hydrochloric acid" and "sodium hydroxide". To me (who is not fluent in chemistry English) that's easier to "decode".
    If you could include the reactions (NaOH + Al -> H2O + ??) too it would be perfect!

    Regards,
    Kåre from Denmark

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