Divide students into small groups to do this experiment, which will help determine what factors influence how quickly water freezes. The teacher should boil water, put it into an ice cube tray and place it directly into the freezer. The groups of students can use previously boiled water that has cooled, hot tap water and cold tap water. Note the time that each batch was placed in the freezer and let the children take turns checking to see when each freezes.
Divide the children into groups and have each group mix 1 cup of cornstarch with approximately 1/2 cup of water in an aluminum foil pie plate. Once the cornstarch mixture feels solid when tapped, stop adding water. This creates a suspension, which is neither liquid nor solid. When the children grab a bit of the mixture in their hands and squeeze it, it will be hard, but as soon as they stop squeezing, it will turn to liquid again.
Give each group of children three clear containers, one with vegetable oil, one with corn syrup and one with water. Try to float different small objects, such as raisins, paper clips or pennies, in each liquid. See if any of the objects float in the liquid with more density but sink in the least dense one. Then pour all three liquids in a larger clear container and let them settle. The most dense one will be on the bottom and the least dense on the top.
Heat up water in a container and add ice to another container of water. Add a little red food coloring to the hot water and a little blue food coloring to the cold water. Pour some of the blue water into a beaker, then, a drop at a time, slowly and carefully add the red water. If the students add it too quickly it will mix, but if they do it correctly, the two colors will layer according to their density. Then, using room temperature water in two containers, see if a raisin floats. Add salt to one container of water and sugar to another, 2 tablespoons at a time, checking to see if the raisin floats after each addition.