Determining whether an egg is fresh or spoiled doesn’t require complex equipment—just a simple glass of water. As eggs age, their internal air cells expand, causing them to behave differently when submerged. Looking at the three test cases in the image, can you spot which egg is no longer safe to eat?
At first glance, all three eggs look almost identical.
But there is one important clue hiding in the way they behave in the water.
Look closely at eggs 1, 2, and 3.
Which one would you avoid eating?
Before revealing the answer, let’s look at what is happening inside an egg as it gets older.
When an egg is freshly laid, the shell contains many tiny pores.
Over time, moisture and some gases slowly leave the egg through these pores.
As this happens, the air pocket inside the egg becomes larger.
That change affects how the egg behaves when you place it in a glass of water.
A very fresh egg usually sinks to the bottom and lies mostly flat.
That is what we see with Egg 1.
Its position tells us that it has a relatively small air cell and is likely fresher than an egg that floats.
Now look at Egg 2.
It has sunk to the bottom, but it is standing more upright.
This can happen as an egg gets older.
The air pocket inside has grown, changing the egg’s balance and making one end rise.
So Egg 2 is generally older than Egg 1, but that does not automatically mean it has gone bad.
Now we come to Egg 3.
This egg is floating near the surface.
That happens because an older egg has lost more moisture and developed a larger air pocket.
The larger air pocket makes the egg more buoyant, so it can float.
For this reason, Egg 3 is the one most likely to be the oldest.
But there is an important detail that many people miss.
Floating does not automatically mean an egg is spoiled or unsafe to eat.
The water test is mainly a rough way to estimate the age of an egg.
It cannot tell you exactly whether harmful bacteria are present.
So if you are checking an egg at home, don’t rely on the floating test alone.
The safest approach is to check the egg’s storage history and condition.
If you decide to use an older egg, crack it into a separate bowl first.
Look for anything unusual in its appearance.
Then check for a strong, unpleasant sulfur-like or rotten smell.
A spoiled egg will often have an obvious bad odor once it is cracked open.
If something seems clearly wrong, it is better to throw it away.
So, what is the answer to the picture?
Egg 3 is the answer if the puzzle is asking which egg is the oldest or most likely to be bad.
Egg 1 is the freshest-looking position.
Egg 2 is older.
Egg 3 is the oldest because it floats due to its larger internal air pocket.
However, remember the key point: the floating test shows age, not definite spoilage.
That small difference is what makes this simple kitchen puzzle more interesting than it first appears.
So, did you pick Egg 3?
