100 Days Project

Nanogirl: Star Science

Nanogirl wants to find 100 friends to do science experiments with her to prove that no matter who you are or what your education level, you can always have fun with science.

Day 28:

Alicia measures the pH of things in from the kitchen

pH is how scientists measure how acidic or how alkaline a lquid is and the the pH depends on both the degree of ionisation (which is a ratio of ions to molecules) as well as how concentrated the liquid is.  The pH scale goes from 1 to 14 with 1 being a very strongl acid and 14 being a very strong alkaline.
If the liquid has a pH of 7 we say it is neutral and 7 is the pH of pure water.

Alicia had a box of universal indicator strips which change colour depending on the pH of the liquid that you dip them in.  Red indicates acid, blue aklali and green is neutral.  We went through the kitchen cupboards and use these strips to measure all the liquids we could find!

From our tests Alicia found that lime juice and vinegar gave a red colour strip indicating they were strong acids.

The vanilla esscence shown in the photo had a pH of 5 which is slightly acidic and a glass of water gave a green result showing it was neutral at pH 7.

Alicia then mixed baking soda with water to make it a liquid and the strip turned dark blue showing that it was an alkali.

After we measured all of the incredients, we mixed everything together to show how adding an alkali to an acid can neutralise it, but we also found out that pouring a baking soda solution into a vinegar solution can results in a lot of bubbles and fizzing!