Teaching the Properties of Water to Lower Elementary Students

National Standard:
A- Develop abilities necessary to do and understand scientific inquiry
H- Construct conceptual connections among science experiences through unifying concepts and processes such as order and organization; evidence, models, and explanation; change, constancy, and measurement; evolution and equilibrium; and form and function.
Grade level: 2
Time required: 40 minutes

Objectives:
Students will demonstrate adhesive and cohesive properties of water.
Students will relate adhesion and cohesion to daily activities.
Process Skills:
Analyzing (formulating questions, identifying components and relationships)
Materials needed:
? Beaker or measuring cup with narrow spout
? Yarn (soaking wet)
? Container to hold water
? Colored water
? Music taped from the Olympics or other sports programs (optional)
? Water
? Paper and drawing materials
? Clear plastic cups
? Two dollars in pennies
? Paper clips
? Fork
? Magnifying glass
? Student recording sheet

Engage
? Show students a beaker partially filled with colored water, an empty container and the yarn
? Tell students you are going to make water defy gravity as it "walks a tightrope"
? Hold beaker and yarn at an angle over the cup
? Slowly pour water down the yarn
? Ask the students if they can explain how the water moves along the yarn
? Tell students they will be conducting several experiments that will help them understand this demonstration and other properties of water.

Explore
? Divide the classroom into four sections, an Olympic event will take place in each section (banners may be helpful to identify each region)
? Demonstrate each of the 3 remaining activities. (Pennies in a cup, floating clips, drops on the head of a penny)
? Ask students questions about each activity as it is demonstrated, i.e. How many pennies do you think will it take for the water to spill? Do you think a paper clip will float or sink? How many drops of water do you think will stay on the head of the penny?
? Distribute Recording sheets to students
? Allow students to participate in each activity in any order, but they may only begin an event if there are less than 8 (may depend on number of students) people already participating. Make sure students understand to take their turns in order for the experiments to turn out correctly.

Explain
? Have students compare their results with those of their teammates
? Have each team record the highest number they got for each activity on the board (or have them tell you their highest score and write it on the board)
? Explain the difference between cohesion (water's attraction to itself) and adhesion (water's attraction to other materials)

Evaluate
? Have students draw a picture of water moving along yarn or of a water drop and identify where adhesion and cohesion occur

Extend
? Compare the surface tension of other liquids
? Using a magnifying glass, investigate drops of water, hydrogen peroxide, and alcohol
? How do they differ? Can a paper clip be supported on the surface of each of these liquids?

Activity borrowed from: Project Wet: Curriculum & Activity Guide. (1995). The Watercourse and the Council for Environmental Education, Montana State University.