NEW ZEALAND TARANAKI

Chemical Rainbow

Now you can make your own rainbow and carry it around with you...


Try this:

  • Dissolve 20 g sugar in 40 mL of NaOH solution and add 5 - 6 drops of Universal Indicator.
  • Pour into a 100 mL measuring cylinder.
  • Layer with 20 mL of equal strength acid containing Universal indicator by tilting the cylinder and dribbling the acid down one side. Don't get acid on you!
  • Leave to settle for 10 minutes.

The Sodium Hydroxide (NaOH) solution is an alkali. Because of the dissolved sugar, it settles to the bottom of the cylinder. The acid floats on top as it is less dense.

The clever bit is using the Universal Indicator solution. Universal indicator is red in acid, green in neutral solutions, purple in alkali.

You might have noticed that when the acid and base meet, they cancel out each other leaving a green coloured neutral solution in the middle. So a base is an acid opposite.

 


FIND OUT MORE:-

  1. Read more about acids and bases here.
  2. Tannic acid can be used to make a type of ink. Try it out here...
  3. Make your own indicator using plant dyes.
  4. Learn about real rainbows here
  5. The interactive pages...identify these pieces of lab equipment
  6. The interactive pages...weird metals and gases hide in this Periodic Table

RETURN TO FUN! Science Activities and Technology Projects

 

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