Big Ideas in the Water Unit
Investigation 1: Water Observations
Part 1: Drops of Water (Water on Surfaces)
*Water forms beads on waterproof materials and soaks into absorbent materials.
Part 2: Surface Tension (Water Drops on Pennies)
*Surface tension causes the skinlike surface of water.
*Drops of water form balls or domes because of surface tension.
*Surface tension can be disrupted (weakened) by the addition of soap.
Part 3: Water on a Slope
*Water moves downhill.
*Larger water domes move faster down a slope.
*The steeper the slope of a surface, the faster a water dome moves.
Part 4: Water in Nature (Outdoor Investigations)
*Water forms beads on waterproof materials and soaks into absorbent materials.
Investigation 2: Hot Water, Cold Water
Part 1: Build a Thermometer
*Water expands when heated and contracts when cooled.
Part 2: Sinking and Floating Water
*A material that floats in water is less dense than the water.
*A material that sinks in water is more dense than the water.
*Cold water is more dense than warm water.
Part 3: Water as Ice
*Water expands when it freezes.
*Ice is less dense then liquid water (so it floats in water).
Part 4: Ice Outdoors
*Ice melts when heated, and water freezes when cooled.
Investigation 3: Water Vapor
Part 1: Evaporation
*Evaporation is the process by which liquid (water) changes into gas (water
vapor).
Part 2: Evaporation Locations
*As temperature increases, the rate of evaporation increases.
Part 3: Surface Area
*The larger the surface area of a volume of water that is exposed to air, the
greater the rate of evaporation.
*Moving air (wind) increases the rate of evaporation.
Part 4: Condensation
*Condensation is the process by which gas (water vapor) changes into liquid
(water).
*Condensation occurs on a cool surface.
*Evaporation and condensation contribute to the movement of water through the
water cycle.
Part 5: Water Detectives
*Evaporation is the process by which liquid (water) changes into gas (water
vapor).
*Condensation is the process by which gas (water vapor) changes into liquid
(water).
*Evaporation and condensation contribute to the movement of water through the
water cycle.
Investigation 4: Waterworks
Part 1: Water in Earth Materials
*Soil is rock particles mixed with organic matter called humus.
*Soils retain more water than rock particles alone.
*Water drains more easily through some earth materials than through others.
Part 2: Waterwheels
*Flowing water can be used to do work.
*Waterwheels are machines powered by flowing water.
Part 3: Water in Soil
*Water drains more easily through some earth materials than through others.