Half gallon paper milk
carton (empty and washed out)
Gallon of water
Awl or 10p nail
Pair of scissors
Pad of paper and pencil to make notes
Do this experiment over
Cut off the top of the milk carton.
From the bottom of the milk carton, measure up 1/2
inch and using the awl or 10p nail punch a single hole
in the center of the side of the carton
Measure up one inch from the bottom and punch another
hole in the center.
Measure up two inches from the bottom and punch a third
hole directly above the other two holes.
Measure up four inches from the bottom and punch a
final hole in the center of the side.
NOTE: All holes should
be the same size.
Take a long piece of tape and tape up all four of the
Put the carton on the edge of the sink with the side
with the holes pointing toward the sink.
Mark a line on the carton near the top. Always fill
or refill the milk carton with water to that line.
Quickly remove the tape thats covering all the
four holes. Watch what happens. Measure how far away each
of the steams hits the sink.
Let all the water empty out. Watch what
happens as the water level drops. What happens to the
steams of water?
Now tape up all holes. Put the carton back on the
sink edge. Refill the carton and remove the bottom tape.
Measure how far out the stream goes. Retape the hole,
and untape the next hole up; measure how far away the
stream goes. Refill the carton with water. Retape the
second hole and untape the third hole; measure how far
away the stream goes. Refill the carton with water to
the same level as before. Retape the third hole and untape
the fourth hole; measure how far away the stream goes.
How far away did the streams of water fall from the
carton. Was there a difference between the stream from
the water from hole the bottom than at the top?
Here's why? Water has weight. The closer to the
bottom of the carton, the more water is above and the
more weight is pressing down from above. The more weight,
the more water pressure. And the more water pressure,
the further away the stream will go and the faster it
Hydroelectric facilities are built at the base of dams
to take advantage of the high pressure of the water
at the bottom of a reservoir. The water pressure is
funneled through a tunnel through the dam called a penstock.
The water then is focused on the blades of a turbine.
Water pressure of the water turns the turbine, and the
turbine turns a generator making electricity.