Properties of Water Density, Surface Tension

 Imagine walking down the street on a rainy day. You see a puddle, and on the top you notice a thin layer of rainbow couloured liquid. Why is that? Density

 This is because of a liquids Density. The oil on top of the rain water is less dense.  Wood floats on water because it is less dense  Boats float better on salty seawater because it is more dense than freshwater.  Usually thicker liquids are the most Dense. Density

 What will happen if a piece of paper is thrown into some water, will it float or sink?  What will happen if the same piece of paper is crumpled and than thrown into the water, will it float or sink?  Why do you think that is? Floating and Sinking

 The paper will float the first time, and sink the second. Why?  Density is the Volume of the object, divided by the Mass.  The flat paper has MORE volume than mass, thus it will float.  The crumpled paper has LESS volume, thus it will sink. Floating and Sinking

 Try this to understand Density a bit better  buoyancy/density_en.html Density Activity

 This photo is a perfect example of Surface Tension.  Small drops of water are usually Round because the water molecules Pull together. The result is a “skin” Formed over the small ball.  Surface Tension is only Strong enough to work on small Balls of water, or filled glasses. Surface Tension

 It is due to this skin that water bugs can walk on water. Examples of Surface Tension

 Understand surface tension with a video!  Surface Tension Video