Science – PH Indicators

For Christmas, one of the fantastic presents Elsa received was a kitchen chemistry set.  She has been nagging me to try it so this week we did the first experiment which was using a natural indicator to find out whether liquids and powders are acid, alkaline or neutral.

Firstly, to make the natural indicator we had to cut and boil up some red cabbage.  We strained it to keep the juice and left it to cool.

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Next, while that was cooling we discussed what we would like to test.  Then she wrote a chart which listed them, included a ‘my guess’ column and a results column.  We chatted about the principles of acids and alkalis so she was able to make a more educated guess.

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After collecting Anna from nursery, we started our tests.  Firstly the girls had to put a bit of the cabbage juice in some test tubes (indicator) and to each tube they added some of the item they wanted to test.

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Results

Vinegar

After adding a few drops of the vinegar to the tube the indicator went immediately pink.  This was a good one to start because the result was so quick and obvious, the girls got excited.

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Water

Anna added water to another tube of the indicator and it stayed purple, which meant it was a neutral liquid.

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Lemon Juice

A few drops of lemon juice to the indicator and it went pink.

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Results of the tubes in order vinegar, water then lemon juice.

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Dishwasher liquid

Adding a few drops of the dishwasher liquid and it went bright pink.

Hand Soap

Adding a bit of hand soap to the cabbage water and it went dark pink.

Baking Powder

Not only did adding baking powder to the indicator cause it to stay purple, it fizzed over the top which caused a few giggles.

In order of results – dishwasher liquid, hand soap and baking powder.

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Salt

Elsa added some salt to the indicator and it stayed purple,

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Sugar

Anna added some sugar to it and it also stayed purple.

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Flour

Adding flour to it changed the colour to light purple but still it stayed purple.

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Final three results salt, sugar and flour.

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We all enjoyed doing this even if we didn’t guess so well at the results. 🙂

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