Today, students were introduced to acids and bases. They learned that acids include things like hydrochloric acid, vinegar, and lemon juice; while bases include things like baking soda, Windex, and bleach. In general, acids will taste sour (we eat them often!) and bases will be slippery to the touch… like many cleaning products!
Students originally thought that only acids could be dangerous, but today it was actually ammonia – a base – that gave us a reason to all wear gloves and safety glasses!
Students also learned that we measure how acidic or basic something is using the pH scale which goes from 0-14. Acids have pH’s below 7, bases have pH’s above 7, and some things — like water — are neutral!
In the activity, students tested a variety of substances including vinegar, ammonia, tap water and seltzer for their pH. First, they added red cabbage juice, a universal pH indicator (a chemical that changes color depending on pH) to their test substances and watched them change color! Then they compared these to pH reference standards, and finally tested the pH using pH test strips (like you might use for a pool or aquarium).