Why Dry Ice Is Perfect for Learning
Dry ice (solid carbon dioxide) is the most accessible example of sublimation. At atmospheric pressure, it transitions directly from solid to gas at −78.5°C, creating dramatic visual effects perfect for hands-on learning.
⚠️ Safety First
Never handle dry ice with bare hands — always use insulated gloves. Work in well-ventilated areas. Adult supervision required for all experiments.
Experiment 1: Fog in a Bowl
Place a small piece of dry ice in a bowl of warm water. The CO₂ gas rapidly cools surrounding water vapor, creating a dense, low-lying fog. This demonstrates sublimation and condensation simultaneously.
Experiment 2: Inflating a Balloon
Drop a small piece of dry ice into a balloon and tie it off. As the dry ice sublimes, CO₂ gas fills the balloon, visually demonstrating the massive volume expansion during a solid-to-gas transition. One gram of dry ice produces about 550 mL of gas at room temperature.
Experiment 3: Singing Spoon
Press a metal spoon against a block of dry ice. The rapid heat transfer causes the spoon to vibrate, producing a high-pitched squealing sound. This demonstrates how sublimation creates a gas layer between two surfaces.
Experiment 4: Bubble Tower
Place dry ice in soapy water. The sublimating CO₂ creates bubbles filled with fog. When they pop, miniature clouds escape — a beautiful demonstration of gas behavior.
Experiment 5: Color-Changing Solution
Add dry ice to water with universal pH indicator. As CO₂ dissolves, it forms carbonic acid, changing the solution's color and demonstrating the chemistry of dissolved gases.