The tribes of the Red Indians in America used to puff smoke signals to one another as warning signs. You may have seen this in some of old western movies. In this experiment we will try to do same but in water and with water.
Things Required:
2 large-mouthed, clear, glass, quart-jars
Red food colouring
Small baby food jar
6-inch square of aluminium foil
Rubber band
Pencil
4 or 5 ice cubes
Directions:
Place the ice cubes in one of the quart jars. Fill the jar with cold water. Fill the baby food jar so that it may over-flow with hot tap water. Add and stir in six or seven drops of food colouring. Cover the mouth of the baby jar with aluminium foil. Use the rubber band to secure the foil around the mouth of the jar. Stand the baby food jar inside the empty wide-mouthed jar. Remove any unmelted ice cubes and pour the chilled water into the container with the baby food jar. Completely fill the jar with the cold water. Use the point of the pencil to make a small hole in the aluminium foil. Slowly and gently, tap the foil with the eraser of the pencil.
This Is What Happens:
The hot, coloured water puffs upward like smoke rings.
Science Behind It:
Water molecules, like all matter, are spaced closer together when cold, and farther apart when heated. The coloured hot water weighs less than the colder clear water because of this spacing. The lighter hot water rises to the top of the heavier chilled water.
Try This Punch a second hole into the foil.
This Is What Happens:
A stream of coloured water starts and continues to flow out of the jar.
Science Behind It:
The cold water sinks into one of the holes, pushing the lighter hot water out.
