September 23, 2008

Today, we talked and did an activity about acidity of vinegar, water, and fruit. The activity we did was called the Acid Test. It taught us that baking soda and acid react to form carbon dioxide, and that baking soda can be used as an indicator of the presence of acid. We then performed the acid/baking soda reaction in a closed system and observed the volume of gas formed by the reaction. We first tested how much acidity was in vinegar and found that vinegar is 100% acidic. We then tested how much acidity was in water, which is 0%. We then tested how much acidity was in a 50-50 mix of water and acid, which is 50% acidic. We then tested how much acidity was in a lime and lemon, which both are 100% acidic. We then tested an orange's acidity which was at 23%. We then tested a grapefruit's acidity which was at 27% acidity. We found out that the more acidic a substance is the more carbon dioxide reaction there is when mixed with baking soda.