Freezing and Melting - Definition, Difference & Examples

Freezing and Melting: Everything around us is made of matter. Matter can be solid, liquid, or gas. When temperature changes, matter can also change its state. For example, when heat is added, ice melts into water. When heat is removed, water freezes into ice. This is how melting and freezing happen.

Understanding what is freezing and what is melting helps us learn how materials behave in everyday life. So keep reading to know the definition of freezing and melting, along with examples.

Read More: What is the Fahrenheit Value of 25 Degrees Celsius?

What is Freezing? – Definition of Freezing

One common question that may arise while studying changing states of matter is: What is freezing? Freezing is the process where a liquid changes into a solid when the temperature drops. 

When heat is taken away from a liquid, its particles slow down and come closer to each other to form a solid. This process is known as freezing. The definition of freezing in science is when a liquid turns into a solid because of cooling. For example, when water freezes, it changes into ice.

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What is Freezing Point?

The freezing point is the temperature at which a liquid changes into a solid. For example, water turns into ice at 0°C, which is its freezing point. When a liquid cools down and reaches its freezing point, the particles in the liquid move slowly and stick together to form a solid.

Different substances have different freezing points. For example, the freezing point of milk is slightly lower than that of water. So, understanding what is freezing point helps us know when a liquid will freeze and become a solid.

Read More: Celsius to Fahrenheit

Freezing Examples

There are many freezing examples that we can see in daily life and in nature. The most common example is water freezing into ice. When water is kept in a freezer, it loses heat and changes into solid ice cubes.

• Another example is melted candle wax solidifying. When a burning candle is turned off, the melted wax cools down and becomes solid again.

• In nature, lava turning into rock is also a freezing example. Lava comes out from a volcano in liquid form and slowly cools down to become solid rock.

• Freezing food is also very common. When food is kept in a freezer, it freezes and stays fresh for a longer time.

• In cold places, seawater freezes and forms sea ice.

• Also, snowfall is another freezing example where water vapor freezes in the sky and falls as snow.

These freezing examples help us understand how liquids can change into solids when the temperature drops.

Read More: Different Types of Materials

What is Melting? – Definition of Melting

Now that we have learned about freezing, it is also important to understand what is melting? Melting is the process where a solid changes into a liquid when heat is added. In simple words, when something solid turns into liquid because of heat, it is known as melting. A very common example is when ice melts and becomes water.

The definition of melting is that it is a physical change where the solid’s particles gain energy, start moving faster, and break away from their fixed positions. Melting is a reversible process. When the melted liquid is cooled again, it can turn back into a solid.

What is Melting Point?

The melting point is the temperature at which a solid changes into a liquid. When a solid reaches its melting point, it starts to melt and becomes a liquid. For example, the melting point of water is 0°C, which means ice turns into water at this temperature.

At the melting point, both solid and liquid can exist together for a short time. It is the temperature where melting happens. Different materials have different melting points. Some solids melt quickly at low temperatures, while others need more heat. Understanding what is melting point helps us know when a solid will start changing into a liquid.

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Melting Examples

We can see melting examples in many things around us. The most common example of melting is ice melting into water. When we take ice cubes out of the freezer and leave them outside, they slowly turn into water because of heat.

• Another common example is the melting of butter on a hot pan when we cook.

• Some more melting examples are candle wax melting when we light a candle.

• Melting chocolate when it gets warm in our hands or under sunlight.

• Glassmaking also uses melting. In glass factories, special materials are heated until they melt to make glass objects. In light bulbs, the thin wire inside is made of a metal called tungsten, which can melt only at a very high temperature.

Examples of melting can be seen in many daily activities like cooking, making glass, making light bulbs, and even making cheese and chocolate products.

Read More:  Separation of Substances

Freezing and Melting Similarities

Freezing and melting may look like opposite processes, but they also have many things in common, as explained here:

• Both freezing and melting are phase changes. This means they both change the state of matter—from liquid to solid or from solid to liquid.

• Both processes are reversible. If we freeze water into ice, we can melt the ice back into water.

• Another similarity is that both happen at the same temperature. For example, water freezes and melts at 0°C. In both freezing and melting, no new substance is formed, which means the material stays the same; only its state changes.

• Also, both freezing and melting can be affected by outside pressure.

So, freezing and melting are connected processes where heat is either added or taken away, but the material remains the same.

Difference Between Freezing and Melting

Freezing and melting are two opposite processes that change the state of matter. Both happen at the same temperature but in completely different ways. Let’s understand them in detail by comparing them:

Direction of Heat Flow

• In melting, heat is added to the substance from the surroundings. The substance absorbs heat to break the bond between its tightly packed particles.

• In freezing, heat is taken away from the substance. The substance loses heat to the surroundings, and its particles slow down and stick together to form a solid.

Temperature

• The temperature at which a solid changes into a liquid is known as its melting point. For example, the melting point of water is 0°C.

• The temperature at which a liquid changes into a solid is called its freezing point. For most substances, the melting point and freezing point are the same temperature. For example, the freezing point of water is also 0°C.

Change in Volume

• Melting: When a solid melts, its volume usually increases because the particles move apart in the liquid state.

• Freezing: When a liquid freezes, its volume usually decreases because the particles come closer in the solid state. (Note: Water is a special case where its volume increases when it freezes.)

Change in Energy

• Melting increases the internal energy of the substance as heat is absorbed.

• Freezing decreases the internal energy of the substance as heat is released.

To sum up, the main difference between freezing and melting is the direction of heat flow. Melting happens when heat is added, and freezing happens when heat is removed. Both are physical changes and can be reversed by changing the temperature.

Read More:  Force and Pressure

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