An experiment that involves two water solutions, one with salt and the other sugar, provides the student an opportunity to learn about evaporation and the properties of water. The experiment requires the student to pour 100 mL water into three glasses, adding 100 mL salt to one, 100 mL sugar to another and leaving the third glass with plain water. The student will then formulate a hypothesis as to which solution will evaporate most quickly. Each day, the student should monitor the three glasses and record their water levels. The glass with plain water will evaporate most quickly, while the solution with salt will evaporate before the sugar solution.
Thermal diffusivity is the speed with which an object conducts heat through a material. By melting a sliver of wax upon heated copper, glass and graphite, students will learn about the properties of these objects and learn which is best for conducting heat. Stand one rod of copper, glass and graphite on a hot plate turned on high. Place paraffin wax on each of the rod's top surface. Before placing the wax on each rod, students should hypothesize as to which material has the highest diffusivity: meaning, which piece of wax melts the fastest. The sliver of wax on graphite will melt first and have the highest thermal diffusivity, while copper will come in second and glass third.
To help students understand the water cycle, rain can be simulated in a classroom experiment. Have the students pour hot water into a glass container and then cover it with a cold plate that's sat in the refrigerator or freezer for an hour. After letting the water sit for two minutes, have the students place ice cubes onto the cold plate that sits above the container. Have students quickly hypothesize what will take place. The cold plate will cool down the air's moisture inside the container, which will then condense, forming water droplets or simulated rain. When forming their conclusions, students should cite the natural process that takes place in the atmosphere when rising warm air meets cold temperatures, which creates vapor condensation and then precipitation.
Heat capacity is the amount of energy needed to raise the temperature of a material. To help the student understand this concept, one rod of copper, graphite and plastic -- each of the same dimensions -- should be placed into three separate beakers of boiling water (100 degrees Celsius). Using a thermometer, measure the temperature of each beaker of water after 1 minute. Before revealing the temperature difference, ask students to hypothesize which objects have the highest heat capacity. The results will show that plastic will have the highest, with graphite next and copper the lowest.