The word acid comes from the Latin word acere, which means “sour.” All acids taste sour. Well known from ancient times were vinegar, sour milk and lemon juice. Acids produce hydrogen ion (H+) in solution and make a blue vegetable dye called litmus turn red. Upon chemically reacting with an active metal, acids will evolve hydrogen gas. Another common acid reaction some sources mention is that acids react with carbonates (and bicarbonates) to give carbon dioxide gas.
Bases are substances which will restore the original blue color of litmus after having been reddened by an acid. All bases taste bitter. For example, mustard is a base. It tastes bitter. Many medicines, because they are bases, taste bitter. Bases feel slippery, sometimes people say soapy. It produces hydroxyl ion (OH-) in solution.
This video explains how to study the properties of acids and bases by their reactions with: (a) litmus solutions, (b) zinc metal and (c) sodium carbonate.