Where’s the Evidence

1. Check back in your notes… what are the ingredients that make sports drinks beneficial? • Water • Carbohydrates • Electrolytes • 6-8% concentration of carbohydrates and electrolytes • Did we prove that our mystery sports drink was “beneficial”? • What happened to the liquid in our mystery sports drink? Where’s the Evidence

2. One way to make sure that it was water which ‘left’ the sports drink is to capture the ‘evaporate’ and test it! • We might find it is pure water, or that it contains other dissolved particles. We might follow a linear path, or it could send us on a detour: “Does this sport drink contain the preferred 92-94% water concentration?”… “What really is in this sport drink?” • Either way is the "road to scientific inquiry". Where’s the Evidence?

3. Video Clip: Solar Water Distiller http://www.youtube.com/watch?v=4sqRvUzqDCE&feature=related One Way to Capture the Evaporate – Solar Water Distiller

4. Commentary: Do you all know the terms evaporation and condensation? Evaporationis the process of a substance going from a liquid phase into a gaseous phase. Like 'water' into 'steam'. Condensationis the process of a substance going from a gaseous phase to a liquid one. Like water vapor (gas) becoming a cloud and then into raindrops. It is the reverse of evaporation. Vocabulary

5. Distillationis a much more involved procedure than just letting stuff evaporate. The basic idea is that boiling a liquid produces steam which can be condensed back into a liquid on a colder surface and then collected again. Impurities tend to be left behind which is why people buy distilled water at the grocery store. It is useful in coffee-pots or other appliances which could easily be harmed by chorine, fluoride and other impurities if we used tap-water. This is a useful in our "sports drink" example because we can boil off the 'water', and then collect it without the electrolytes and carbohydrates. We can then test our "distillate" to make sure it really is water and nothing else. Distillation

6. What do you think the distillate will look like? Prediction

7. Questions: What color is the distillate? Does that surprise you? What does the distillate smell like? Do you think this is pure water or do you think something else is still in the fluid? How could we find out?