Chemistry Unit- Day 4

Mixtures and Separation

First we talked about what a mixture was and they came up with some examples. Then I had them mix the first set of tubes in front of them- chick peas and sugar. And I asked them what the best way to separate them would be. Both Rylan and Cale said to add water at first, but I told them I wanted the sugar back, not have it washed away.

So we talked about the first way to separate a mixture: filtration. Cohen and Lakin poured out the sugar/chick pea mixtures into a colander to separate.

Then I gave them the second set of tubes- water and soil. Which Cohen and Lakin shook up real good while I had Rylan and Cale think of how to get the soil back out. They both agreed that the colander wouldn't work, but that a smaller filter would. So Rylan poured his out into a coffee filter to separate and while it drained we talked about an other option.

While we had been talking the second tube had been sitting there untouched. So when I asked them to look at it they saw the second way of separation: settling. We set the tube up on the shelf to allow it to settle completely.

Then they each got a one tube containing water and one containing sugar. I had them combine them and shake until the sugar was dissolved. Then I asked for them to give me the sugar back. I had them start by using the previous 2 methods. Cale poured his through a coffee filter, Rylan set his up to settle. And after some discussion we set Cohen's on the windowsill to evaporate the water and leave the sugar.

Since everyone agreed that evaporation would leave the sugar behind, I asked them for the water back too. If it evaporated it would be gone....

So we went into the kitchen to try distillation. We only caught a little bit of the steam to condense back into water then we just let the steam go and watched the sugar crystals form back in the bottom of the pot.

We talked a little bit about why you would want to capture the gas as it evaporated. How some gases are harmful to the earth or to people. Then they ate what they could scrape out...


  1. That's the best way to end a project...scraping the bottom for sugar.