Cabbage haters can turn their leftovers into litmus paper

[William Finucane] is making his own litmus paper by harnessing the power of cabbage. The process is much easier than the faux gunpowder he made, as it take just the one ingredient and a few kitchen tools.

In case you’ve forgotten your High School chemistry, Litmus is a set of dyes that change color when exposed to basic or acidic materials. It is common in liquid form, or as a paper. [William] is getting his dye from the leaves of red cabbage by running half a head through a blender with just a bit of water. Once that is reduced to pulp and boiled in the microwave (mmm, must smell great!) he separates the liquid using a coffee filter. A fresh coffee filter serves as a donor for the substrate, just dip some strips in the cabbage juice and let them dry. You can test them with some Ammonia as seen in the video after the break, or just start grabbing whatever is under the sink and see what happens.

Comments

  1. thatcherc says:

    Not to burst a bubble, but this is in every kids’ science experiment book. The process is usually just boil up the red cabbage and dip in some paper towel.

  2. PI says:

    Red Hibiscus flowers have the same property.

    • Hydrox says:

      Neat man! Thanks for the tip.

      We actually did this as part of our curriculum @ school and I can testify that blended cabbage smells to high heaven, works surprisingly well and consistently though.

  3. Ken Quast says:

    If anyone is interested in the dye behind this color reaction I just posted on my site. There are two posts, one on acids and bases, and one on anthocyanin and extraction with distilled water, 70% ethyl alcohol, and acetone.

    http://www.observationsblog.com/sciencetechnologyexperiments.html

  4. tz2026 says:

    Litmus is a specific pH indicator derived from lichens that turns Red in acid (pH < 7), and blue in base/alkali, but is purple in very slightly basic solutions. "Litmus Paper" means one with using this specific dye, not any pH indicator.

    Cabbage is a different indicator. I've found colored paper that turns red in acids (even mild like vinegar).

  5. dan says:

    put the cabbage juice on eggs whilst they are frying,

    this is how to make green eggs and ham. now once your kids have read green eggs and ham, you can teach them how to make green eggs and ham!

    clearly cabbage juice doesn’t turn to ham, you’ll have to cook that separately!

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