physical change
Học thuậtThân thiện
Definition
Noun: A physical change is a process where a substance changes from one state of matter (solid, liquid, or gas) to another without altering its fundamental chemical composition or identity. The molecules themselves remain the same; only their arrangement, energy, and distance from each other change.
Usage
This term is used primarily in scientific contexts, especially chemistry and physics, to describe phase transitions. * It is a countable noun (e.g., a physical change, several physical changes). * It is often contrasted with a chemical change.
Examples
- The melting of ice into water is a physical change.
- Boiling, freezing, and sublimation are all examples of physical change.
- When water evaporates, it undergoes a physical change from a liquid to a gas.
Advanced Usage
- Reversibility: A key characteristic of a physical change is that it is often easily reversible by changing physical conditions (e.g., temperature, pressure). For example, water vapor can condense back into liquid water.
- In a Sentence: "Although the substance changed state during the physical change, its molecular formula remained unchanged."
Variants and Related Words
- Phase change (n): A more technical synonym for physical change, focusing on the transition between states of matter.
- State change (n): Another common synonym.
- Physical (adj): Relating to physics or the properties of matter and energy. (e.g., ).
Synonyms
- Phase transition
- State change
- Phase change
Antonyms
- Chemical change: A process where one or more substances are altered into one or more new substances with different chemical properties.
Noun
- a change from one state (solid or liquid or gas) to another without a change in chemical composition