Phases of Matter Video
Physical and Chemical Changes Video
The below image shows the reaction of aluminum foil in copper (II) chloride solution. Note the appearance of the colored solution layers. Where the reaction is complete you see the new brown solid (copper) is floating in the aluminum chloride (colorless) solution. At the bottom layer you see the left over original blue copper chloride solution that has not reacted.
The observed signs of a chemical change for this reaction include a color change in both the solution and solid produced (silver solid vanishes and forms a brown solid; the blue solution becomes clear). There was also gas produced (as seen by bubbles forming on the foil during the first few minutes of the reaction)
Mixture Separation Techniques