Phases of Water

Paul Doherty

triple point0.006 _

bar

Gas

Water vapor is invisible

Water Gas ?Liquid drops are visible.

Water vapor bubbles in a liquid are visible.

At the triple point Solid, Liquid and gas exist together in equilibrium.

At the critical point gas and liquid become indistinguishable.

0.006_bar

Sweat droplets on skin: evaporation, (not eqilibrium.)

The vapor pressure above water is higher than above ice.

Water Boiler

Reduce the presure on water and it will

boil at room temperature.

BubblesPin = Pout + 4T/r

Pressure in a bubble increases as radius decreases.

Where T is the surface tension in N/m

Surface tension is a result of the attractive forcs between molecules.

Water FreezerFreeze water by lowering

the external pressurecausing boiling

and temperature reduction.

Boiling is a cooling process.

Geyser

The temperature of the water

increases slowly.

The pressure can change at the speed

of sound. Creating an

eruption.

Liquid water in contact with solid water

Ice is a mineral, water is molten ice.

Liquid Water Soid Water, iceless dense.

Density of Water

Vs

Temperature and

Pressure

At 1 bar Ice floatson water

To see an icebergFloat an ice balloon

Ice

hexagonal crystal

Electric dipole moment of water.red -

blue +

Walking among large antarctic ice crystals

Large antarctic ice crystal

Ice takes on the structure of liquid water, near the surface at temperatures near 0 °C, this

makes ice slippery.

Supercooled rain crystallizes when it hits a surface.

Without a nucleation site the homogenious nucleation temperature is -42C

Frezing is a warming process, freezing water releases heat.

Watch Water Freeze

In this exhibit water is cooled below freezing and remains a liquid until a

“seed” causes ice crystal nucleation.

Then the entire liquid crystallizes.

A 20 cm diameter snowflake.Supercooled water nucleated freezing into a hexagonal crystal.

Water made from

lighter isotopes evaporates

more rapidly.

Here, water is Solid Liquid and Gas in contact butNOT

in equilibrium

Yellowstone Norris Geyser Basin

Mars atmosphere has places at the triple point of water

Here water ice has crystallized as snow on Mars. Image from the Viking Lander.

Mars Phoenix Lander Water Ice

Water Ice on Tempel 1

at -100C vaor pressure is 0.0014 Paat 20 C it is 2300 Pa

Ice at -1 C hardness 1.5 Mohs scalehardness 4 at -44Chardness 6 at -80 C

ice carved granite in antarctica.

It’s more complicated than that.

MOre of the phase diagram of water.

On Europa Ice 3 may form.It is denser than liquid water.

A water ocean on Europa may be sandwiched between ice 1h on the top and ice 3 on the

bottom.

Pluto Ice geology

Pluto water ice in blue

Enceladus

Enceladus Geysers

Titan Rivers

Titan Hydrocarbon Lakes

Titan SurfaceWater Ice Boulders

Mars Salty water Streaks

Mars Seasonal Water Flow

Superheated water