Grade Level: 7th – 10th; Type: Chemistry
When an acid and a base combine, the base neutralizes the acid in a chemical reaction. This is how antacids work as well. This project will test which antacids are most potent in neutralizing lemon juice.
- 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
- 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.
- Rinse the eyedropper thoroughly.
- Add ten drops of lemon juice (an acid) to each test tube.
- Label each test tube with the name of one of the liquid antacids you are testing.
- 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.
- In a table such as the one below, record the number of drops needed to neutralize the acid.
- Repeat this process with the remaining types of antacids, adding drops of one antacid to each of the remaining test tubes.
- 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.
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.