The Lost Volume Demonstration

Equal volumes of water and ethyl alcohol do not add up to their combined total volume when mixed. Instead, the mixture shows a reduced volume due to molecular interactions between water and alcohol.

1. Measure 250 mL of water and pour it into a beaker or graduated cylinder.
2. Measure 250 mL of ethyl alcohol in a separate container.
3. Slowly combine the two liquids into one container.
4. Observe and record the total volume of the mixture, it should be significantly less than 500mL.

Volumes Don't Always Add Up - Flinn Scientific:

📄 The Lost Volume Demonstration - Carolina Knowledge Center: https://knowledge.carolina.com/professional-growth/activities/the-lost-volume-demonstration/

• Try mixing different ratios of water and alcohol to see how the volume reduction changes.
• Use other alcohols (such as isopropanol) to compare volume contraction.

• Keep alcohol away from open flames or sparks, as it is highly flammable.
• Conduct the experiment in a well-ventilated area to avoid inhaling vapors.
• Do not ingest alcohol or dispose of it down the drain without proper guidance.

• Why does the total volume decrease when water and alcohol are mixed?
• How do hydrogen bonding and molecular structure explain the volume contraction?
• What does this experiment suggest about the difference between mass conservation and volume conservation?