PSI Barbering Practice Exam

An example of a physical change is:

1. Ice Melting

2. Rust Forming

3. Wood Burning

4. Cooking an Egg

The correct answer is: Ice Melting

Ice melting is indeed an example of a physical change because it involves a change in the state of matter—specifically, from solid to liquid. This process occurs when heat is applied, causing the molecules in the ice to gain energy and move apart, resulting in water. Importantly, a physical change does not alter the chemical composition of the substance involved; in this case, the chemical structure of H2O remains the same whether it is in solid form (ice) or liquid form (water). In contrast, rust forming, wood burning, and cooking an egg are examples of chemical changes. Rust formation involves a reaction between iron and oxygen, resulting in iron oxide, which has different chemical properties from the original materials. Wood burning leads to combustion, creating ash, gases, and other compounds, fundamentally altering the wood's structure. Similarly, cooking an egg involves denaturation of proteins, which changes its properties and chemical composition, making it a chemical change as well. Understanding the distinctions between physical and chemical changes is crucial in fields such as chemistry and barbering, particularly regarding the properties and reactions of products used in hair treatments.