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W15 Make salt, sugar and citric acid invisible = Dissolving
Every child knows: Sugar disappears in the tea after stirring. Now you are to investigate this behaviour with 3 white substances from the kitchen. In the next experiment you will investigate what happens when the 3 solution are left for alonger time.
What to do
Let a small quantitity of 3 white crystals disappear in 3 big drops of distilled water.
Material
Tray, drinking straw spatula (cut diagonal), 3 matches or tooth sticks for stirring, Blister, dropper bottle with distilled water, crystals of sea salt, sugar, citric acid.
Experiment
1. Use a drinking straw spatula to make 3 small quantities of the substances on a black plastic surface - like seen in the left photo. (Alternative: in 3 blisters or on the bottom of the tray).
2. Add 3 drops to each of the piles. Mix the solids with the water, keeping the liquids separated from each other (right photo).
Observation
Sugar, salt and citric acid cannot longer be seen. (If a white turbidity remains with salt try another salt sample).
Eplanation
The reason for disappearing of the solids: The grains are divided in smaller and smaller particles that are even invisible on the best microscope.