Eco-celli Mercury-free Barometer for Schools Liquid barometers definitely have a place in our schools as a teaching device allowing students to actually see the affects of atmospheric pressure on the liquid in the barometer. An electronic digital barometer cannot provide this visual reinforcement as all the students see are numbers changing, much like a digital clock. The problem with liquid barometers is that they are made using mercury. Less complicated is the Eco-celli barometer:
The same accuracy as a mercury barometer in measuring atmospheric pressure. The barometer is named the Eco-celli after Evangelista Torricelli, the inventor of the barometer. The Eco-celli contains no mercury. The U-shaped glass tube is filled with an environmentally safe red silicon fluid and gas. Because of the length of the barometer tube, the barometers scale is four times larger than a standard mercury scale making it much easier for a student to read.
The precision thermometer is filled with blue colored methyl alcohol. An increase or decrease in temperature can cause the fluid in the barometer to expand and affect the pressure reading. This is corrected by setting the movable scale, which is attached to both the barometer and thermometer, to the top of the blue fluid in the thermometer.
The Eco-celli barometer costs 1/2 less than a comparable mercury barometer. Given the low cost and and safe operation, replacing mercury barometers in the classroom now is a sensible option. We have two models we recommend for school use. The E038 model: glass or acrylic and the E729, a bit more decorative.
Hygrometer - psychrometer. How to show what humidity is.
A psychrometer is one of the most effective instruments used to measure the water vapor content-or the amount of moisture or relative
humidity-in the air.
How does it work?
The psychrometer consists of two Celsius thermometer tubes. The red
tube measures the actual ambient temperature-referred to as the dry
bulb temperature. The base of the blue tube is immersed in a vessel
containing a muslin wick soaked in water. This tube measures the
temperature caused by the effects of evaporation from the saturated
wick. This temperature reading is referred to as the wet bulb
temperature. The relative humidity (%) of the air is then calculated by
crossing the dry bulb and the wet bulb temperature readings on the easy
to read chart beneath the tubes.
It is one of the most easy and accurate methods of determining the relative humidity. One of our psychrometer has a dedication to
astronomer Anders Celsius (1701 - 1744) printed at the top. Art n° P 1.
The psychrometer is very durable and affordable but its most important
feature is that educators can maintain the learning benefits of
students seeing the effects of moisture on temperature. Digital or
aneroid substitutes sacrifice the visual physical principles that are
evident with liquid instruments.
Click Here to see all our available psychrometers: