Icebergs are dangerous to ocean-going vessels in part because only about 1/8 of an iceberg is seen. The rest is under water. Conduct an experiment to determine if there is a significant difference between how fresh and salt water affect the ability of an ice cube to float. Make a supersaturated salt water solution by boiling a small pot of water and continuing to add and stir in salt until no more salt dissolves. You know the solution is saturated when adding more salt simply causes it to accumulate the bottom of the pot. Pour the salt water solution into a cereal bowl and fill another bowl with pure water. Let the water in both bowls settle to room temperature. Put an ice cube in the bowl of pure water. Tie a piece of thin, black thread around the cube at the level where the water hits the cube. Remove the cube, place it in the salt water solution and compare the water level on the cube to the string marker. Observe if there is a difference between the two levels. Conclude if more of an iceberg is above water in fresh or salt water.
After a snowstorm, everything is covered with frozen precipitation. Melting begins once the temperature rises above freezing. Observe different materials to see if melting occurs faster on some surfaces than on others. Inspect the metal hoods of cars, concrete pavements, asphalt driveways, glass car windshields, grass-covered soil and other materials. The melting is quantified by using a ruler to periodically measure and record the height of the snow on each object. Also record the time, note whether or not the sun is shining and whether or not the color of the underlying material has an effect.
When the temperature in the air is below freezing and the air is saturated with water vapor, ice particles begin to form on various objects. This is especially dangerous if road surfaces become slick, and is inconvenient to drivers who must scrape ice off of their car windows. Frost usually forms at night, when the air is coolest. On an evening when frost is predicted, periodically check various surfaces of items around your home, such as the metal and glass on a car, wood on a picnic table, concrete in the sidewalk and the asphalt on the road. Determine if frost accumulates on some surfaces before others. Mix three parts vinegar to one part water and pour it into a spray bottle. Spray the solution on a car windshield before the frost forms and evaluate its effectiveness.
Convection is the circulation of air or water currents that move because of a difference in temperature. In an empty aquarium tank, light a punk and use modeling clay to stand it upright. Smoke is unburned carbon particles, and allows the observer to follow the movement of the air. Watch to see how the smoke travels out of the aquarium. Line the bottom of the aquarium with ice cubes, creating a layer of cold air along the bottom. Light the punk, observe the movement of the air and note if there is any change. Place the tank in a warm, sunny window and note if there is any change in air flow by watching smoke from the punk.