Thursday, May 19, 2011

Mixtures: Home Mixture Separation

Mix up some salt, poppy seeds, iron filings and sand, in about equal proportions. 

Give each student a small sample of the mixture and challenge them to take the mixture home and separate the components. 

The students need to return the separated components, as well as a description of the steps they followed in the separation. 

The original version of this lab requires a parent signature for credit.  It also has students rate how successful they were in separating and recovering each component (on a scale of 1-10) and asks them what they might do differently if given the same problem to solve.

It's a nice way to remind students that science does not have to occur in the lab and it does not necessarily require fancy equipment.  It's also a chance to involve parents and for students to actually show their parents what they've been learning in class. 

If you have students for whom it may truly be a problem to complete the activity at home, I would allow them to schedule a time to work on the activity in the classroom. 

One story.... I once had a student who claimed to have dissolved the salt in water and later boiled off the water to leave the salt.  The only problem was, the salt sample he handed in looked like salt straight from the shaker.  When you reclaim the salt through this procedure, it doesn't look like salt that comes straight from the canister, instead it's kind of flaky and a little powdery.  Busted!

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