Properties of Water

Properties of Water Experiments

Part 1: Adhesion

  • Fill a small graduated cylinder with 10 ml of water.

    • Observation: The level of the water may curve slightly at the edges due to adhesion.

    • Reasoning: The water molecules are attracted to the molecules of the graduated cylinder, creating a concave surface.

Part 2: Cohesion

  • Place a drop of water on a piece of wax paper.

    • Observation: The water is repelled by the wax paper, forming a bead rather than spreading out flat.

    • Reasoning: The cohesive forces between water molecules are stronger than the adhesive forces between water and the wax paper, leading to water rolling around instead of spreading.

Part 3: Surface Tension

  • Get a penny.

    • Prediction: Estimate how many drops of water will fit on the penny.

    • Experiment: Place drops of water onto the penny until the “bubble” pops.

    • Result: Count and document how many drops fit.

    • Extension: Add soap to the mix.

    • Experiment: Spread a drop of soap on the penny, then add water drops again.

    • Expectation: Adding soap will interfere with the surface tension, allowing fewer drops to remain before the bubble breaks.

Part 4: Cohesion via Glass Slides

  • Place a drop of water between 2 glass slides (like a sandwich).

    • Experiment: Try to pull the slides apart.

    • Observation: It may be difficult to separate the slides due to the cohesive forces of the water molecules.

    • Reasoning: The attraction between water molecules creates a force that resists the slides separating.

Part 5: Diffusion of Food Coloring

  • Place a drop of food coloring into a cup of water.

    • Observation: The food coloring spreads and does not stay in one place.

    • Reasoning: The diffusion process occurs because molecules are moving from an area of higher concentration (the drop) to lower concentration, illustrating the movement of solute in a solvent.

Part 6: Testing pH Levels

  • Test the pH of tap water and alkaline water.

    • Recording Results: Document the pH values.

    • pH Scale Overview:

    • Acid: 0-6

    • Neutral: 7

    • Basic (Alkaline): 8-14

Chemistry of Life

Properties of Water

Structure of Water

  • Chemical Composition: Water is represented as H2O.

  • Molecular Interactions:

    • Molecules form hydrogen bonds (H-bonds) with each other.

    • The +H ion is attracted to the –O ion, resulting in water's cohesive properties and creating a