What are some natural processes that represent physical and chemical changes?
Examples of natural processes that represent physical changes include:
- Melting: The process of converting a solid into a liquid state when heat is applied. For instance, ice melting into water.
- Freezing: The process of converting a liquid into a solid state when heat is removed. An example would be water freezing into ice.
- Evaporation: The process of converting a liquid into a gaseous state due to an increase in temperature. For example, water evaporating into vapor when exposed to sunlight.
- Condensation: The process of converting a gas into a liquid state due to a decrease in temperature. An instance of this is water vapor condensing into droplets to form clouds.
- Sublimation: The process by which a solid directly converts into a gaseous state without passing through the intermediate liquid phase. For example, solid dry ice (frozen carbon dioxide) sublimating into carbon dioxide gas.
Examples of natural processes that represent chemical changes include:
- Rusting: The process of iron combining with oxygen in the presence of moisture to form iron oxide (rust).
- Burning: Also known as combustion, it is the chemical reaction between oxygen and a fuel source that produces heat, light, and various products, such as carbon dioxide and water. For instance, wood burning in a fire.
- Photosynthesis: The process by which plants, using sunlight, convert carbon dioxide and water into glucose (sugar) and oxygen.
- Digestion: The biochemical process in the human body that breaks down food into simpler substances through chemical reactions facilitated by digestive enzymes.
- Fermentation: A process carried out by microorganisms, such as yeast, to convert sugars into alcohol and carbon dioxide. This process is used in making bread, beer, and wine.