Geysers (geography / Physics)
A geyser is a water spring which discharges
(erupts) water (along with dirt) turbulently (violently) now and then steam
comes out steadily. The geothermal energy and expansion of vapour
at low pressures and high temperatures causes the geysers.
The formation of geysers is a
hydro-geological phenomenon under certain conditions. They are
nearby volcanoes and due to the presence of magma. The
small holes in Earth are called “surface vents”.
There are fractures, fissures, porous spaces, cavities in side
Earth’s crust. There is water available inside Earth up to the depth of
about 10 km. The rocks are very very hot there. This
system of water reservoir holding water, getting heated and coming out through
the vents is called a plumbing system. Along these vents
SiO2 or geyserite is deposited and makes the vents smooth and
hard. They enable high pressure to be maintained along the
After certain duration, the pressure of water inside Earth comes
down, so geysers stop. The water on the surface seeps through pores in
Earth and this slowly collects back into the reservoirs of the geysers.
Thus the geyser cycle again starts.
They exist in about 1000-1500 places on
Earth. There are a lot of them in the USA, especially at
Yellowstone National Park at Wyoming. The Grand geyser in USA erupts for
about 10 minutes every 12 hours. There is a valley of Geysers in Russia
in Kamchatka peninsula. This is the major one in Euro-Asia. In
India there are some including one famous one in Hariyana.
There are around 80 in El Tatio , Chile. There are some in Taup
Volcanic zone in (North island of) New Zealand. It is supposed to
have reached 160 meters high. In Iceland too there are famous
geysers including the Great Geysir.
Working principle (Physics)
The Joules heating effect of an electric resistance is used
to heat water.
Description of the heater:
We use electric geysers at homes or in clinics or shops to heat
water. It is cylindrical shaped and is mounted on walls. It has a
capacity of 50 to 250 liters. See diagram.
It consists of a water container vessel with an inlet for cold
water and an outlet for hot water. The heater contains a thick (tubular)
electric conductor (metallic resistance) coil element. It gets heated due to
the dissipation of energy when current passes through it. The heat energy is
transmitted to water through conduction and convection mechanisms. Usually the
heating element is made of Nickel or chromium.
There is a mechanism to measure the temperature of water
using a thermostat. It shuts off, automatically, the current supply to the
heating element, when the temperature is above a preset value. This is set in
the factory. There may be LEDs or small bulbs to indicate whether the
heater is switched on or off.
The water container is usually made of a material which does not
get corroded or rusted easily. The water container is protected with
insulating material and air gap so that the heat energy is retained inside the
container. The materials for the outer casings are usually stainless
steel, plastic and china glass. Plastic is safer to prevent from leakages and
Power and rating related information:
The heater is usually based on AC voltage. It is given
a rating : power it consumes, current it passes when the rated voltage is
applied. Voltage rating V could be 220 V in countries like India and 110 V
in USA. Power rating P could be 1 KW to 5 kW depending on
Heating Power P = V² / Resistance of heating coil.
If the water tank capacity is L liters, then rate of
= P / (L * density *
specific heat ) = P / ( L * 1 * 4181) =
= P / (4181 L) °K /
If we want to heat water from 20° to 50°, then it takes time T
T = 30 * 4181 L /
P = 2000 L / P minutes.
If people could wait for 15 minutes for L litres , then
needed P = 2000 L / L = 2 kW
We get instant heaters also. They have a
small capacity (2 litres). The water is heated at a constant rate as the
water flows through the geyser. There is no storage and not much
insulation provided in this type of heaters. A heating (electric
resistor) coil is used in them. The wattage could be around 2 kW. Care
must be taken as if there is not enough water, it may burn the coil. Flow
of water can be decreased or increased to have hotter or colder water.