1. Separation Techniques Separation lab follow up

2. Physical Size  By looking at your cup of materials, it may be obvious that because of the physical size of some objects as well as the low quantity, it would be wise to remove these items by simply picking them out.  Tweezers, or even your hands can be used to remove the rock salt  Think back: Many students were inclined to add water immediately to their cup. Why would this be a poor choice before removing the rock salt and/or iron filings? (address BOTH in your response)

3. Magnetism  The magnetic property of the iron filings allow them to easily be removed by using a magnet tool. The magnet can be scanned slowly over the remaining materials.  Think back: Can you keep the materials in the cup, and remove the iron filings by dipping the magnet in the cup and removing it? Why might spreading the pile out thinly and scanning the magnet along the surface a better option?

4. Buoyancy  The buoyancy (ability of something to float) of poppy seeds makes them easy to separate from the remaining materials by adding water. Once water is added, and the mixture is stirred, all of the poppy seeds will float to the surface  There are a few options for how the poppy seeds should be separated from the water’s surface and gotten alone  You can decant the surface water off and send it through a filter paper (see next slide). To decant is to carefully pour liquid from one container to another without disturbing the precipitate. In this case, the precipitates are the non soluble materials that remain in the cup.  Another option would be to scoop the poppy seeds off the surface with a spoon or metal scraper. This option may be more time consuming, but would produce the same results.  Think back: Should the decanted water be saved, or is it okay to discard? Are any of the six materials soluble (able to dissolve) in water?

5. Filtration  Filtration is used to separate liquids from solids. Much like using a strainer to separate your noodles from boiling water when making mac & cheese, filter paper is permeable only to the liquids, leaving (nearly) all solids behind.  Anther example is a coffee filter. Grounds get left in the top of the machine, while hot water and the soluble coffee “flavor” drip through.  How to fold filter paper:

6. Evaporation vs. Distillation  From our prior experiences in both science class and cooking yummy mac & cheese, we know that evaporation is simply when liquids increase in temperature until they reach their boiling point, turn into a gas, and escape into the surroundings. But doesn’t distillation have to do with boiling water too? What is the difference between the two separation methods?  While both methods deal with boiling a liquid, the method of distillation uses an apparatus (pictured below) that collects the gas being formed which then condenses in a separate container. This liquid is now more pure, free of any soluble material, or liquids with a higher boiling point.  Think back: in this lab, the material you wish to collect is the granulated salt, which is dissolved in the water. Because of this, distillation isn’t a necessary action. The pure evaporated water does not need to be collected and can be boiled off. When might someone need to use distillation? Use either a real life example, or a scientific example.