Does it Dissolve? Can it be Separated? Is the Change Reversible? 6 Jun 2013

In Tamar we have been investigating different powdered solids to find out if they dissolve, can be separated and whether the change that occurs when they are mixed with water can be reversed.

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Mr Wild prepared 10 different powders for us to explore. We had to predict what the powder was and carefully observe what happened when it was mixed with water.

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We used 2 different digital microscopes to look at the powders before they were mixed with water. We dropped solutions onto slides to look for evidence of granules in a solution under the microscope.

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We used filter paper to separate solutions to see if they had dissolved completely.

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We used ‘diffusion’ to observe coloured solutions (coffee and powdered paint).

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We worked together in groups to predict, observe, record and conclude.

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We noticed that when some solids settle their sediments form layers, with heavier grains sinking to the bottom of the container first.

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We found that some mixtures could not be separated after mixing them with water, and that the change was irreversible as a chemical change had taken place. Some of us used Netbooks to record our findings in a table. We used vocabulary such as: sediment, diffusion, separation, evaporation, absorption, settling, dissolving, solution, solute, solvent, stirring, reversible and irreversible…

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