Science: Testing pH Experiment

 Hi there!

Today I will be writing about an experiment I did today in Science class.

Aim: 

To test pH of a range of household chemicals

Method: 

1. Add a few drops of each chemical to a spot on your spotting tile. If a substance is solid or powdered you will need to mix it with a few drops of water before testing it. 

2. Test the chemicals with litmus papers.

3. Test each chemical with a few drops of Universal indicator. 

Results: 

Chemical being tested	Colour in blue litmus	Colour in red litmus	Colour in Universal indicator
Toilet Cleaner	Red	Red	Red/Orange
Floor Cleaner	Violet/Blue	Violet/Blue	(Dark) Green
Vinegar	Red	Red	Pink/Orange
Baking Soda	Blue	Blue	Turquoise

Discussion:

This is the pH scale. It shows the different pH levels, they vary from 0-14. 0 being the strongest acidic pH and 14 being the strongest alkaline/basic pH. There is a neutral pH level too, it is not acidic, but it is not an alkali either, this level of pH is 7 which is also the middle number of the pH scale. In this scale, red would signify that the pH level is extremely acidic, dark blue would signify that the pH level is basic/alkaline. 

There are 3 different ways to measure pH, red litmus paper, blue litmus paper and Universal Indicator. The litmus papers don't show how strong the chemical or solution is. Red litmus paper turns blue if put in an alkaline solution and remains red if put in an acidic solution. Blue litmus paper turns red in an acidic solution, it remains blue if put in a basic solution. 

Here are some examples: 

• Saliva has a pH of about 6, this means it is a weak acid. It also means it would be light green on the pH scale for the U.I. (Universal Indicator).
• Toilet cleaner turned red in blue and red litmus paper, meaning it was acidic. 
• Both litmus papers turned dark blue when placed in floor cleaner, this showed that they were a base. When U.I. was dropped into the floor cleaner, it turned green. 
• When U.I. was dropped into Vinegar, it turned an orange-pink colour, signifying it was a stronger acid. When the litmus papers were put in, they both turned red, showing it was an acid. 
• Baking soda turned blue when U.I. was dropped in, the same happened when litmus paper was placed in too. This would mean that baking soda is a base. 

Conclusion:

I enjoyed doing this experiment a lot. I was able to test various chemicals and see their pH levels. I liked seeing how quickly the litmus paper and Universal Indicator would react to the chemicals I chose to experiment on. It was interesting seeing what colour the Universal indicator would change to also. I would have liked to have tested more chemicals but apart from that, I really liked this experiment. 

Thanks for reading!