Physical Changes Physical changes involve a change in the form or properties of an object without changing the object's composition or the interactions betwe...
Physical changes involve a change in the form or properties of an object without changing the object's composition or the interactions between its components. Examples of physical changes include melting ice, boiling water, changing the temperature of an object, and crushing a can.
Changes in form:
A balloon popping
A melting ice cube
A metal wire stretching when heated
Changes in properties:
A rock dissolving in water
A metal reacting with oxygen
A flower blooming
Physical properties are those that describe the characteristics of an object without changing its chemical composition. Examples of physical properties include:
Shape: A ball, a book, a tree
Size: A pencil, a chair, a flower
Color: A red book, a blue sky, a yellow flower
Density: A solid has higher density than a liquid
Elasticity: A rubber band, a piece of wood
Thermal conductivity: A good conductor conducts heat quickly, while a poor conductor does so slowly
Physical changes can be reversible or irreversible. Reversible changes can be undone, such as melting ice. Irreversible changes cannot be undone, such as burning wood.
Chemical changes involve a change in the composition of an object, resulting in the formation of new substances. Examples of chemical changes include:
Rusting iron
Baking a cake
Mixing chemicals to create a new solution
Changes in composition:
Iron rusting in the sun
Baking soda and vinegar reaction
Dissolving salt in water
Chemical properties are those that describe the characteristics of a substance that determine its chemical behavior. Examples of chemical properties include:
Reactivity: Some substances are more reactive than others
Solubility: Some substances dissolve in water, while others do not
pH: A substance's ability to conduct electricity
Reactivity: Some substances react with oxygen, while others do not