with thread or string. Attach the funnel to
the manometer with a 30 cm length of
rubber tubing. Push the funnel into a pail of
water and watch the manometer.
How to Make a Water
Pressure Gauge with a
Funnel Sensor
Connect two 15 cm lengths of glass
tubing or two transparent plastic soda
straws with a short length of rubber
tubing and attach them to an upright
as shown in the diagram.
Put some coloured water in the tubes
to a depth of about 6 or 8 cm. This is
your pressure gauge or manometer.
Cover a small funnel with thin rubber
stretched tightly and tie it securely
Water pressure changes with depth
Fill a tall glass jar or pail with water. Use
the manometer and funnel sensor to
measure the pressure just below the
surface. Next, measure the pressure at the
bottom. How does pressure change with
depth?
Pressure depends upon the liquid
Get two glass jars into which the funnel will
fit. Fill one with water and the other, to the
same depth, with a less dense liquid such
as alcohol. Measure the pressure at the
bottom of the jar of water. Measure the
pressure at the bottom of the jar of alcohol.
How do they compare for the same depth?