Salt dissolves in water and disappears completely
Salt dissolves in water and disappears completely. Tanya says this is a chemical change, because the salt no longer looks like salt at all. Her friend says it is still a physical change. Who is right?
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Start thinking on Socho →More disagreements in Changes Around Us: Physical and Chemical
A candle's solid wax melts into liquid and then cools back into solidAdding a few drops of food colouring to a glass of water turns the water pinkAn iron rod is cut with a saw, and an identical rod is left out in the rain until it rustsMilk turns into curd, and curd does not turn back into milkTanya says fast changes are chemical and slow ones are physical — so iron rusting (slow) i