|Does an egg float?|
|Question Date: 2018-01-10|
Yes, but only if its old and not good to eat!
Fresh eggs, or good to eat eggs, will not
float. This is because egg shells have very very
tiny holes in them, and over time air outside the
egg can go through these holes and into the inside
of the egg. New eggs have hardly any air in them
(just egg white and egg yolk), which is why they
Egg will sink or float in the water, depending the
age and conditions of the egg.
Usually the fresh egg will sink into the bottom of
cold water. But if the egg ages, the egg could
float in water. The truth is that even though the
egg has a shell, it is porous which means air can
go inside or outside the egg.
On the other hand,
as time goes on, the slow decay inside the egg
will turn the egg white and yolk into gas, which
could escape through the porous shell. The water
inside the egg could also evaporate over time. In
another word, if the egg ages, it will slowly lose
its weight because of the slow decay and water
evaporation. But the buoyancy from the eggshell
itself stays pretty much the same over time, it is
not surprising the egg will float eventually if
the weight lose is too much such that the buoyancy
could totally counter the weight (floating).
A fresh egg does not float. It will sink to the
bottom of a bowl of water (the water needs to be
deep enough to submerge the egg). An egg that
floats has gone bad and should not be eaten =).
Depends on how much gas there is in the egg. Maybe
you should put an egg into water and let us know!
A simple answer to this is no, but that
assumes that you have a new egg and are placing it
into fresh water. In that case, the egg would
not float because it is more dense than water.
However, an old egg could have a lower density
than fresh water (because some of the material
inside the egg is able to pass out through the
shell), and a new egg could have a lower density
than non-pure water (e.g. sea water). Whether or
not an object will float in a fluid (not to be too
confusing, but a fluid is any substance which can
flow, not strictly a liquid) essentially
depends on whether the weight of fluid displaced
by the object is greater than the weight of the
object itself. A detailed description with
eggs and water can be found in this earlier
If you want to go even further, you can
consider putting your egg into other fluids. An
easy example is air. (While air is a gas, it is
also a fluid.) Since eggs do not bob around in the
air like helium-filled balloons, we can conclude
that eggs are more dense than air. On the other
hand, mercury, which is a metal that is liquid at
room temperature, has a density nearly 14 times
that of water, and both new and old eggs would
float in it.
This question has a really fun answer because
eggs float – sometimes! When an egg is fresh
then it will sink in a glass of water but when it
is rotten it will float. How could this
be? It turns out that the shell of an egg
slowly allows air to sneak inside, the same way
that a balloon slowly lets air leave even when the
end is tied. Overtime, more and more air will
enter the egg making it more buoyant (able to
float). When this much air has entered the egg,
it is no longer good to eat. The air that
spoils your egg is the same air that causes the
egg to float. You can test this at home! Go get a
few eggs and place them in a cup of water. If they
sink then they are still fresh, if they float, you
can probably throw them out. Thank you for your
If you submerge an egg in water, the egg will
displace an amount of water equal to the volume of
the egg. This is similar to when you get into a
bathtub; the water level in the tub will rise
because your body displaces the water in the tub.
If you could collect only the water that is
displaced by the egg and weigh this amount of
water, it will give you what is called the
buoyant force, which is the upward force
exerted by the water on the egg. This principle
was discovered by the ancient Greek mathematician
and scientist Archimedes and is called
Archimedes’ principle. If the egg is heavier
than the equivalent amount of water that it
displaces, then it will sink because the force of
gravity is stronger than the buoyant force. On the
other hand, if the egg is lighter than the amount
of displaced water, then it will float.
Therefore, to decide if something will float we
need to look at its density and compare it to
water. Density is the mass (amount of stuff)
compared to its volume (the size of the
stuff). An egg has a density that is slightly
larger than pure water, so it will sink, because
it will be heavier than an equal volume of water.
However, you can increase the density of water by
adding salt to the water. The density of salt
water is greater than pure water because there is
more mass (due to the salt) in the same volume. So
if you add enough salt to the water then the egg
will float. You may notice this if you ever swim
in a salt lake or in the sea. You will find that
you float a lot easier in salt water than in a
fresh water lake.
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