AIM OF THE EXPERIMENT: To find out how large an opening has to be for water to pour out of a can.
MATERIALS: three empty fizzy-drink cans, paper napkins, scissors, sticky tape.
MATERIALS: three empty fizzy-drink cans, paper napkins, scissors, sticky tape.
Изображение
Fill all three cans with water from the tap.
Wipe the water off the cans with a napkin.
Cut two strips of sticky tape 3 cm long.
Leave the opening of one of the cans uncovered (A).
On the second can cover three quarters of the opening (B).
Cover half the opening of the third can (C).
Tilt the cans over the sink one after another at the same angle.
Watch how the water pours out of the cans.
RESULTS: Water pours quickly out of can A, does not pour out of can B at all, and drips from can C.
WHY? Water, like all liquids, takes up a definite space — just as air does. When water pours out of the cans, air has to take its place. The opening of a fizzy-drink can is large enough for water to pour out through its lower part while air comes in through the upper part. If three quarters of the opening are covered, air will not get into the can and the water acts as a plug. When only half of the opening is covered, air does get into the can, but not at once — some water pours out before the air gets inside. Because of this the water does not run in a steady stream but drips. METHOD:
Wipe the water off the cans with a napkin.
Cut two strips of sticky tape 3 cm long.
Leave the opening of one of the cans uncovered (A).
On the second can cover three quarters of the opening (B).
Cover half the opening of the third can (C).
Tilt the cans over the sink one after another at the same angle.
Watch how the water pours out of the cans.
RESULTS: Water pours quickly out of can A, does not pour out of can B at all, and drips from can C.
WHY? Water, like all liquids, takes up a definite space — just as air does. When water pours out of the cans, air has to take its place. The opening of a fizzy-drink can is large enough for water to pour out through its lower part while air comes in through the upper part. If three quarters of the opening are covered, air will not get into the can and the water acts as a plug. When only half of the opening is covered, air does get into the can, but not at once — some water pours out before the air gets inside. Because of this the water does not run in a steady stream but drips. METHOD: