Science project

Antacid Potentcy

Research Questions:

  • How do antacids work?
  • Which antacid is most potent?

Have you ever had heartburn? If so, you may have used an antacid to soothe your upset stomach. An antacid is essentially a base that neutralizes your stomach acid. In this project, you can test out which antacid is most potent – at least on the acid in lemon juice!


  • Grape juice (no sugar added)
  • Eye dropper
  • Lemon juice
  • Several test tubes
  • Several different types of liquid antacids

Experimental Procedure:

  1. Add ten drops of grape juice to each test tube. Grape juice is a natural acid-base indicator, so it turns colors depending on whether the solution it is placed in is acidic or basic.
  2. Rinse the eyedropper thoroughly.
  3. Add ten drops of lemon juice (an acid) to each test tube.
  4. Label each test tube with the name of one of the liquid antacids you are testing.
  5. Add the first antacid, drop by drop, to the first test tube. Stop as soon as the solution changes colors. A color change means that the antacid has neutralized the acid in the lemon juice.
  6. In a table such as the one below, record the number of drops needed to neutralize the acid.
  7. Repeat this process with the remaining types of antacids, adding drops of one antacid to each of the remaining test tubes.
  8. Record your data. Which antacid neutralized the acid most quickly? What does that tell you about that antacid?

Terms/Concepts: Acids and bases; Neutralization; What causes upset stomach?

References: Easy Genius Science Projects with Chemistry, by Robert Gardener, pp. 46-47.

Disclaimer and Safety Precautions provides the Science Fair Project Ideas for informational purposes only. does not make any guarantee or representation regarding the Science Fair Project Ideas and is not responsible or liable for any loss or damage, directly or indirectly, caused by your use of such information. By accessing the Science Fair Project Ideas, you waive and renounce any claims against that arise thereof. In addition, your access to's website and Science Fair Project Ideas is covered by's Privacy Policy and site Terms of Use, which include limitations on's liability.

Warning is hereby given that not all Project Ideas are appropriate for all individuals or in all circumstances. Implementation of any Science Project Idea should be undertaken only in appropriate settings and with appropriate parental or other supervision. Reading and following the safety precautions of all materials used in a project is the sole responsibility of each individual. For further information, consult your state's handbook of Science Safety.

Add to collection

Create new collection

Create new collection

New Collection


New Collection>

0 items