Physical Changes: Melting — Reading Comprehension

Melting is a fundamental process that transforms matter from a solid state to a liquid state. This process is observed in everyday life, such as when ice cream softens on a hot day or when snow turns into puddles. Scientists study melting to understand how energy and matter interact, which is essential in fields ranging from climate science to engineering. The underlying mechanism of melting helps explain why some materials change state at specific temperatures.

How Melting Occurs: Energy and Particle Movement

Melting is classified as a physical change because the substance remains the same, even though its form changes. The main driving force behind melting is the absorption of energy, typically in the form of heat. When a solid absorbs energy, its particles (atoms or molecules) begin to vibrate more rapidly. At a certain temperature called the melting point, the particles have enough energy to break free from their fixed positions. The solid then transitions into a liquid, where particles move more freely but remain close together. For example, the melting point of pure ice is 0°C (32°F). The energy required for this change is called latent heat, and the process is endothermic—meaning energy is absorbed, not released.

Examples and Applications of Melting

Melting can be observed in many familiar situations. Ice cream left in the sun absorbs heat and melts into a creamy liquid. Butter in a hot pan quickly turns from solid to liquid as energy is transferred from the pan. On a larger scale, melting snowmen in spring or melting glaciers in polar regions both occur because of increased temperatures. These examples illustrate how the amount of energy absorbed and the material’s melting point determine when and how fast melting happens. Scientists also use melting in manufacturing, such as melting metals to shape them into new tools or products.

Melting and the Environment

Melting is not just a laboratory phenomenon; it has important environmental impacts. The melting of glaciers and polar ice caps is a major concern in climate science. As Earth’s temperature rises, more ice melts, contributing to rising sea levels. Understanding melting helps scientists predict environmental changes and plan for their effects. Melting also connects to broader scientific principles, such as the conservation of energy and the behavior of matter during phase changes.

In summary, melting is a physical change where energy transfer allows solids to become liquids. This process is vital in natural systems and human technology, demonstrating the interconnectedness of energy, matter, and the environment.

Interesting Fact: Some metals, like gallium, have a melting point so low (about 30°C or 86°F) that they can melt in your hand!

What is melting?

What is the melting point of pure ice?

Which term describes a change where the form of matter is altered, but the substance stays the same?

What is the energy needed to change a solid into a liquid at its melting point called?

What does 'endothermic' mean in the context of melting?

Why do glaciers melt as Earth's temperature rises?

If butter melts in a hot pan, what causes this change?

Which statement best summarizes the main idea of the passage?

True or False: Melting is a chemical change.

True or False: Melting of glaciers can contribute to rising sea levels.