What is the attraction between these molecules? Does capillary action involve adhesion or cohesion? Surface Tension In the Classroom Place drops of water on a variety of substances to test surface tension. Drops can be placed on paper, wax paper (or draw a solid rectangle with crayon on paper to simulate wax paper), paper towels, glass, plastic, fabric, plant leaves, etc. Record the substance and any observations. Why does water bead up on some substances, like wax, and soak into others, like paper? Can you explain how an insect appears to on “walk water”? Why on water? can’t all animals walk What would happen if an insect tried to walk on a nonpolar liquid (molecules that do not have charges)? Predict what will happen when you lay a paperclip on top of each surface. Try it out! Does the paperclip float on top of the water? If so, why does this work? Solubility Challenge!!! What happens when you put salt in a cup of water?
What is the attraction between these molecules? Does capillary action involve adhesion or cohesion? Surface Tension In the Classroom Place drops of water on a variety of substances to test surface tension. Drops can be placed on paper, wax paper (or draw a solid rectangle with crayon on paper to simulate wax paper), paper towels, glass, plastic, fabric, plant leaves, etc. Record the substance and any observations. Why does water bead up on some substances, like wax, and soak into others, like paper? Can you explain how an insect appears to “walk on water”? Why can’t all animals walk on water? What would happen if an insect tried to walk on a nonpolar liquid (molecules that do not have charges)? Predict what will happen when you lay a paperclip on top of each surface. Try it out! Does the paperclip float on top of the water? If so, why does this work? Solubility Challenge!!! What happens when you put salt in a cup of water?