Properties of Water Surface tension of water • all you're going to need for this experiment is a bowl of water a bar of soap a plate some paper clips some colored water and chili flakes all you need to do is pour your colored water onto your plate, sprinkle the chili flakes on top try to make sure that they're evenly distributed place your bar of soap into the middle of the plate and you'll see very quickly that the chili flakes get pushed away this is because water has a high surface tension which makes pepper flakes float on top when the soap is added to the water. Soap destroys the surface tension in the area right around the soap. • to take a paper clip and try and put it into some water you'll see that it sinks straight down if you want to make your paperclip float on top of the water take one of them and bend it in half to create an L shape then rest another paperclip on top and very gently lower it into the water you'll see that the paperclip floats on top of the water the surface tension means that there is a sort of skin on the surface of the water where the water molecules hold on tightly together if the conditions are right they can hold tight enough to support the weight of your paper clip the paper clip is not truly floating but it's being held up by the surface tension many insects such as water Striders use this skin to walk across the surface of a stream or a lake • Explanation, the pepper floats on top of the water due to surface tension of the water the surface tension pulls the top of the water together like a skin so the water bulges up a bit. Surface tension is the result of a strong attraction between molecules in a liquid. Water has an unusually high surface tension compared with most other liquids because water molecules are very strongly attracted to each other. This strong attraction allows the water to bulge up a bit and make some insects able to skate on its surface. When the dishwasher gel is put into the water, the surface tension of the water gets ruptured and the bulged part of the water spreads out. So, water molecules on the surface are pulled towards the ends of the bowl, when the detergent meets the water. When the surface tension of the water breaks the topmost molecules of the water spread out, and in the process, they take the pepper particles away, Thus making it look as if they are running away from the liquid soap Solvent properties of water • Take 3 glasses of water, put salt, baking soda and oil in each glass and mix. • Salt dissolves, baking soda (dissolves) precipitates and oil doesn't dissolve. • Salt and water forms ionic compound due to ion dipole interactions which forms hydration shells. • Water and baking soda forms polar compound so they dissolve in water by dipole dipole interaction and hydrogen bond • Water and oil doesn't dissolve because oil is hydrophobic and it forms nonpolar compound Thermal properties of water • Take 2 balloons, 1 filled with water and the other air. Place both the balloon on a fire, have only the water balloon stays. • The air particles inside the air-filled balloon gets high kinetic energy from the heat, so the particles collide expand until it explodes. • Black sooth appears, because the strong hydrogen bond have effect on the physical properties of water causing high melting point and boiling point, as it requires very high energy to break the strong Hydrogen bonds. cohesion and adhesion of water • Cohesion is the attraction between similar molecules • Water is extremely cohesive as each molecule may have four hydrogen bonds with other water molecules in a tetrahedral form • Adhesion is the attraction between unlike molecules • That's why water is attracted to the coin. • Cohesion and adhesion helps explain phenomenon such as meniscus surface tension and capillary action. • Have use a paper and a marker for capillary action. Density of water • Use 4 glasses of water with two coloured. The coloured water is cold water and the transparent is hot water. Fill the hot water and the cold water full and then flip the cold water glass on the hot water glass and vice versa • The coloured cold water goes down and transparent water remains up • When you heat up water, the water molecules start moving around faster and faster. They bounce off each other and move farther apart because there are more space between the molecules, a volume of hot water has fewer molecules in and weights a little less then the same volume of cold water so hot water is less than dense than cold water • When you put the two together with hot water on the bottom the hot water rises to the top mixing with the cold water along the way and creating a different colour as they mix • Thus, ice cubes and icebergs floats. Aquatic organisms can survive in cold climates because lakes and rivers freeze from top to bottom.
