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Hey Folks,
I'm looking for resources on teaching separating mixtures. What separation techniques do you usually teach your on-level students vs honors students? How do you present the information to them? etc.
I'm also looking for worksheets or something like that which gives them scenarios to respond to. Like "If you have a mixture of sand, salt, and iron shavings how would you separate them?" etc.
Thank You!!
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Use magnets to separate the iron filings then dissolve the salt in hot water and filter out the sand. Put the filtrate somewhere to evaporate the water and collect the salt crystals after a few days.
Many garbage companies separate recyclable materials. Air to blow out the paper, magnets to remove iron from aluminium, plastics can be separated by density (use varying concentrations of salt water to change the density).
I have done the first separation with grade school students - high school students depending on their experience. Researching and finding a way to separate garbage might require a bit more experience or ingenuity.
If you need more ideas - contact me I retired recently and am willing to provide any help I can.
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Hi Chris,
I have students separate a mixture of dirty water. I model separation techniques of filtration, etc and have them devise a three step process to clean a mixture of water, oil, coffee grounds, tea leaves, and garlic. They vote on the cleanest final sample of the class. we finish with a reading on how water is cleaned at a treatment plant and they compare this with their procedure. This year I had them create blogs for lab reports and they include pictures of the initial sample, procedure and final results. Time intensive but authentic.
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Dow chemical has a program about purifying water and relates it to the need for clean water in underdeveloped countries. Clay flower pots filter water, you can evaporate water in a large clear plastic bag using a light or sun light and the condense the vapor for pure water, sand and charcoal filter out pollutants but not bacteria, someone has made a plastic straw that can be used to get drinking water and lasts about a month, there are also tablets used by campers to purify water. You could have students compare the results of several of these methods. Maybe some could be used if water supplies were compromised by a hurricane.
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This is great info! I will definitely check into these and make part of the "Cleaning a Mixture of Dirty Water" lab task.
Thanks!
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I assign my honors students a role as a particular type of chemist. Ex: Flavor chemist, petroleum chemist, etc. They have a solve a problem that their role would encounter in industry that is based on a separation technique. They need to research and discuss the career for the role they have taken and then they have to research their separation technique. For example, my petroleum chemists research fractional distillation and how it is used in industry. Students work in groups of four and then have to make either a poster presentation or powerpoint with their information.
I use this as part of their summative assessment for the Unit.
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This seems pretty interesting...how long do you generally give them? All in class or on their own time?
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THanks for the information! I've done the water filtration lab a long time ago. My coteacher made some pretty nasty water...haha
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So random question.
We are giving them a mixture of sand, salt, and wood shavings
They are going to pour water into it as an "extraction" to separate the salt from the sand. In that process the wood shavings should float to the top. If they scoop the floating wood out, is that a decantation? or is there a different name for that?
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Yes, it is a decantation. Next time add iron filings. I hand my students a closed test tube that is layered with sand, salt, wood shavings, and iron filings. I instruct my students to make both qualitative and quantitative observations. I then have them invert the test tube and mix up the contents. Again they are instructed to make observations. Once finished, I tell them to now put the test tube layers back the way they were originally. Students should have measured and drawn pictures labeling their layers. I give different arrangements to each group. If you do not want to work with these materials then you can purchase a kit from Educational Innovations that can be reused each year. Educational Innovations Mixture Separation Kit I have used this kit successful in the past.
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