demonstrations:acid_in_the_eye

Acid In The Eye

Materials: ★★☆ Available in most school laboratories or specialist stores
Difficulty: ★★☆ Can be done by science teachers
Safety: ★★★ Only to be attempted with adequate safety procedures and trained staff

Categories: Acids and Bases

Alternative titles:

Summary

This demonstration shows how strong acids and bases irreversibly damage proteins using egg whites as a model for the human eye. When acid is dropped on egg white, it denatures the proteins, turning them opaque and simulating permanent eye damage.

Procedure

  1. Place egg white in the Petri dish.
  2. Position the dish on an overhead projector or under a document camera (optional).
  3. Add several drops of a strong acid (such as hydrochloric, sulfuric, or nitric acid) to the egg white and observe it immediately become opaque.
  4. Attempt to rinse with water or sodium bicarbonate solution and note that the damage cannot be undone.

Eye Safety Demo - All Things Chemistry:


📄 Acid in the Eye - Flinn Scientific: https://www.flinnsci.com/api/library/Download/a85735243805438b84ffa3fb05d121d7
📄 Acid in the Eye - Flinn Scientific: https://www.flinnsci.com/api/library/Download/a85735243805438b84ffa3fb05d121d7

Variations

  • Try using acids of lower concentrations (though the effect is less dramatic).
  • Repeat the experiment with sodium hydroxide solid or solution.
  • Use different visual aids (such as slow-motion video or magnified projection) to highlight the denaturation process.

Safety Precautions

  • Wear chemical splash goggles, chemical-resistant gloves, and a chemical-resistant apron.
  • Perform nitric acid demonstrations in a fume hood, as it is toxic by inhalation.
  • Do not eat or handle egg whites as food once used in the lab—they are treated as chemicals.
  • Handle all acids and bases with care; they are corrosive and can cause severe burns.

Questions to Consider

  • Why does the egg white become opaque when acid is added?
  • How does denaturation change protein structure and function?
  • Why can the damage not be reversed by rinsing?
  • What does this experiment teach about the importance of wearing goggles in the lab?
  • How is this related to real-life chemical exposure in the eyes?