BAKERSFIELD, Calif. (KERO) — This is the time of the year when many of us find our fridge filled with colorful, hard-boiled Easter eggs. Once you’ve peeled and eaten the egg, the painted eggshell usually goes to waste. But in this Easter edition of Science Sundays, we use that shell to learn about chemical reactions.
Items needed:
- Eggs (hardboiled or raw eggs will both work or just an eggshell)
- Vinegar
- A Glass
Optional: an antacid tablet
Safety precautions: Have children wear goggles or wash their hands immediately after handling vinegar to avoid it getting in their eyes.
Procedure: This is a very simple experiment, with just two steps.
- Step One: Place the egg or the eggshell in a glass.
- Step Two: Add vinegar to the glass, enough to fully cover the shell. As soon as you add the vinegar, you'll begin to see some changes! Bubbles will begin to form on the egg and eventually float up to the top of the glass. This is the chemical reaction taking place!
What's happening: What you're seeing is a chemical reaction between the eggshell and the vinegar. The eggshell is made of calcium carbonate (a base), and the vinegar is made of acetic acid (an acid). Acids and bases are the opposite of each other and usually react when added together.
In our case, the calcium carbonate and acetic acid combine to form three new products: Water, a salt called calcium acetate (which is immediately dissolved in the water so we don't see it), and carbon dioxide gas. The carbon dioxide gas is the bubbles we see forming during the experiment!
Real-world applications: Another important result of combining an acid and a base is that it neutralizes the acid, or makes the acid weaker. We use that fact in our daily lives whenever we take an antacid tablet.
Antacid tablets (things like Rolaids or Tums) help to weaken the acid in your stomach and can help relieve things like upset stomachs and heartburn.
Interestingly enough, most antacids are actually made of calcium carbonate, the same thing eggshells are made of! So if you drop an antacid tablet in some vinegar, you'll see the same reaction!
