Is Cooking An Egg A Chemical Change Or A Physical Change?


Eggs are a versatile type of food that can be used as either an ingredient in a larger dish or cooked in a wide variety of ways. Whether fried, poached, added to cake batter or anything in between, eggs are a rather ubiquitous part of most kitchens. However, you maybe wondering whether cooking an egg is a chemical or physical change? 

Chemical Change Versus Physical – What’s The Difference?

To answer this question we must first understand what the difference is between a chemical change and a physical one.

Chemical Change

When a chemical change occurs, the changed object in question will change from one substance into another or multiple new substances. When this happens, this change is either impossible or nearly impossible to reverse.

An example of a chemical change is when wood is set on fire. This is because the heat and flames are burning the wood and breaking it down. This causes it to blacken before transforming into ash and smoke. Additionally heat, light and sound are given off.

Is Cooking An Egg A Chemical Change Or A Physical Change?

Physical Changes

Physical changes occur when an object changes its state or form whilst maintaining its original substance. When this happens, these results can be either irreversible or reversible.

An example of a physical change is the reaction of water to heat. When this happens the solid of water loses its shape and becomes a liquid and well boiled gas. However, this process is reversible as seen when water changes from a liquid to a solid as it freezes or from steam to liquid when it cools.

Is Cooking An Egg A Chemical Change Or A Physical Change?

So Is Cooking An Egg A Physical Or Chemical Change?

Cooking an egg is a chemical change. This is because when cooked, the heat denatures the proteins which changes their properties and composition. The most clear ways this happens with eggs are when they’re fried for something like egg fried rice. When fried the egg white texture will change from a clear gooey liquid into a solid and when the egg yolk hardens. 

This is not the only chemical change that eggs can go through when exposed to heat though. If using eggs instead of other options as a bonding material in baking, any property or state recognisable as an egg is lost.