# Does a hard boiled egg float?

## Introduction: The Mystery of the Floating Egg

Have you ever wondered why some eggs float while others sink in water? The floating egg phenomenon has been a subject of curiosity and many myths. Some people believe that floating eggs are bad, while others think it is a sign of freshness. In this article, we will delve into the science behind egg buoyancy and put some of these myths to rest.

## The Science of Egg Density

The density of an egg is determined by its mass and volume. Eggs have a hard outer shell, a membrane, and two distinct parts: the yolk and the white. The yolk is denser than the white, and both are denser than water. The density of an egg decreases as it ages due to the loss of moisture and carbon dioxide through the porous shell. As the egg loses moisture and carbon dioxide, the air cell inside the egg becomes larger, and the egg becomes less dense.

## The Buoyancy Principle Explained

Buoyancy is the upward force exerted by a liquid or gas that opposes the weight of an object placed in it. The buoyant force on an object is equal to the weight of the fluid displaced by the object. If an object weighs less than the fluid it displaces, it will float. Conversely, if an object weighs more than the fluid it displaces, it will sink.

## Testing Egg Buoyancy: The Experiment

To test the buoyancy of an egg, place it in a bowl of water. If the egg sinks to the bottom and rests horizontally, it is fresh. If it stands on one end, it is still good to eat but not as fresh. If it floats to the top, it is not safe to eat, and you should discard it.

## Factors Affecting Egg Buoyancy

The age of an egg is one of the main factors affecting its buoyancy. Fresh eggs have denser yolks and whites, making them heavier than water, while older eggs have larger air cells, making them less dense. The size of the air cell, the amount of carbon dioxide, and the moisture content also affect the buoyancy of an egg.

## Do Fresh Eggs Float?

Fresh eggs will sink to the bottom and rest horizontally in water. This is because they have a smaller air cell, denser yolks and whites, and less carbon dioxide. The eggshell is also less porous, preventing water from seeping in and increasing the egg’s weight.

## Does the Age of the Egg Matter?

Yes, the age of the egg does matter. As an egg ages, it loses moisture and carbon dioxide, and the air cell inside it grows larger. This makes the egg less dense and more likely to float. However, the egg is still safe to eat as long as it does not have an off smell or taste.

## Can Saltwater Affect Egg Buoyancy?

Yes, saltwater can affect egg buoyancy. Adding salt to water increases its density, making it easier for objects to float. If you place an egg in saltwater, it will float higher than in freshwater because of the increased buoyancy of the saltwater.

## Other Factors to Consider

Other factors that can affect egg buoyancy include temperature and elevation. Cold water is denser than warm water, which can affect the buoyancy of the egg. At higher altitudes, air pressure is lower, and water boils at a lower temperature, which can also affect the buoyancy of the egg.

## Conclusion: The Truth About Floating Eggs

In conclusion, the buoyancy of an egg is determined by its density, which is affected by its age, air cell size, carbon dioxide content, and moisture content. Fresh eggs will sink to the bottom of water, while older eggs are more likely to float. Adding salt to water can increase its density and affect the buoyancy of the egg. Ultimately, the floating egg phenomenon is not a sign of freshness or spoilage but merely a scientific principle at work.

#### Elise DeVoe

Elise is a seasoned food writer with seven years of experience. Her culinary journey began as Managing Editor at the College of Charleston for Spoon University, the ultimate resource for college foodies. After graduating, she launched her blog, Cookin’ with Booze, which has now transformed into captivating short-form videos on TikTok and Instagram, offering insider tips for savoring Charleston’s local cuisine.