Quarter 1 Section: 1.4 Name:

Activity:Adhesion, Cohesion, and Surface Tension DemonstrationAdhesion is the ability of water to stick to other substances. For example, water can stick to the side of aswimming pool. Cohesion is the ability of water molecules to stick to themselves (H-bonds). We can alsosee that water has a high water tension, a measure of how hard it is to break the surface of water. In thisportion of the lab, you will test these three processes and apply them to capillary action.• Water forms very cohesive bonds that can sometimes defy gravity. In this demonstration, you will predicthow many drops of water will fit on a penny before it spills over and repeat. Repeat the experiment againwith your sodium chloride solution.Plain water Predicted Drops = __________ NaCl Water Predicted Drops = __________Actual Drops = __________Actual Drops = __________Plain water Predicted Drops = __________ NaCl Water Predicted Drops = __________Actual Drops = __________Actual Drops = __________Explain how cohesion was shown in the activity.Explain how adhesion was shown in the activity.Surface Tension Activity• The surface of water is extremely hard to break. Fill the plastic cup to the top so that the water isbarely above the top of the cup without spilling out. Try to get your paper clip to float on top of thewater without sinking. Once you get it to float, carefully drop sodium chloride slowly into the water.How long does it take before the paper clip suddenly sinks?Why does the paper clip sink after adding sodium chloride?Capillary Action Demonstration1. Fill the cup about three-quarters of the way to the top with water.2. Add drops of food coloring until the color of the water is dark (at least five drops). Stir until the coloris evenly distributed throughout.3. Cut about 2.5 cm off the bottom of the stalk of celery with the knife and place the celery in the cupwith the leaves sticking up.4. Check the stalk several times throughout the day. Observe how the leaves are changing. Let the stalksit overnight.