1. 07 Solubility And dissolving salt Science By the Horns Summer 2006 To get back to activities page: http://128.83.243.140/ScienceByHorns/activities.html

2. Foss Kit Connection Explore saturation in FOSS kit where emphasis is on conservation of mass And/or focus on saturation by –Measuring 40 ml of water into a container –Have each group measure in salt in either 1 ml or 1/4 tsp amounts –(start with 5 quick ones) –Add this set amount, replace top, then shake until the salt disappears –Repeat until a few grains of salt remains on the bottom of the bottle (make sure you’ve shaked it vigorously) –The solution is saturated

3. Foss Kit Extension Histogram the results with Post-It TM Notes where each group places its results. You may want to repeat this experiment; Compare the results from the two trials (You may want to do the Histogram and Likeliness Activity before this). Discussion questions: –Where is the data “centered” –If 2 trials, how alike? Different? –Where is the salt going? –If you tasted the water, what would it taste like? (This means the salt has not changed. Dissolving is a physical process, not a reaction [where the salt would be changed]

4. Shifting Saturation and Making Hot Chocolate While discussing results heat the water bottles in hot water (hot pot) What happened to the salt at the bottom? Where did it go? Heating makes water more energetic so it can pick up more salt. Think of examples where this happens at home. Have you ever tried to put hot chocolate into cold water … yech! … But when you heat it, what happens? More hot chocolate can go into solution.

5. What if we cooled it…? If we now cooled the solution and waited a long time, the salt would come out of solution. May want to use sodium thiosulfate pentahydrate to show what would happen (available from UT). Note the temperature as solidifies. (Gives off heat as gets more ordered … increased entropy as heated; heat comes out as cooled).