Liquids at freezing point:One night I was
thirsty for a drink, so I hiked downstairs and opened the
fridge. I keep my fridge on the lowest setting and from time to time things will end up frozen near the back. I was not in the mood for a
soda or
juice and grabbed a
bottle of water. For some reason unknown to myself I
shook the bottle and it responded with freezing itself. I found this rather odd and decided I would find out why this happened.
After very little time in my
physics class I stumbled on the the subject of
heat, and learned the reason behind what happened. When liquids are kept at their exact freezing point, they will not freeze. This is because during any
phase change, there is an extra amount of
energy transfer needed to either break
bonds or to bond the matter together. This is because all the energy transfer related to the object at this time is used for this change, and it should be noted there is no
temperature change during a phase change too. This energy for a phase change is known as
latent heat. When I shook the bottle of water, there was a rise in
kinetic energy that was used to power the phase change to a
solid.
Why large bodies of water don't freeze:
If you have ever visited an
ocean,
sea, or
lake in freezing conditions, you most likely noted that the above stated body of water was unfrozen. This may seem odd to you that a near by
pond has frozen but this has not. Why this happen also has simple physics to blame.
Water's
density is highest at 4 degrees
Celsius (this because water molecules are
polar and become less dense when they align themselves to freeze). So, as the the surface begins to lower in temperature, once it hits 4 degrees, that water will sink to the bottom of the body of water and a new, less warm layer will surface to have its temerature reduced. In
shallow bodies of water, there are few layers to go through and this can happen quickly, but
deep bodies of water can take ages to get through each layer. Only after each layer has hit 4 degrees can the temperature drop below this point. Another fun yet trivial fact is that most large bodies of water will have 4 degree water at their deepest point, this is because 4 degree water is the most dense water and will sink to the bottom.