Physical or chemical change? That is the question…

Physical changes in matter When matter undergoes a change in size, shape, or phase, it is a physical change. Breaking glass, cutting wood, grinding coffee are all physical changes. Is freezing water a physical change? Physical changes do not change the particles that make up matter. The arrangement of the particles, however, may be moved around during a physical change.

Physical changes in matter Are you causing a physical change when you mix sugar and water? A mixture of salt or sugar and water can be compared to a mixture of water and pebbles. The pebbles can be separated with a strainer. Salt or sugar particles are too small for you to separate by hand or strainer. However, the water can be boiled away, leaving the salt or sugar behind.

Physical changes help shape the earth’s surface…

Chemical changes in matter In a chemical change, particles of one substance are changed in some way to form particles of a new substance that has new and different properties. The production of heat or light, the appearance of gas bubbles, and the formation of a solid all indicate that a chemical change has taken place.

Example of Chemical Changes in Matter!! Fireworks Rust Burning wood Cooking

Physical vs. chemical change The earth’s surface is shaped by chemical changes as well as physical changes. Gases in the atmosphere and water combine with minerals in rocks to create new substances. These chemical changes weaken rocks so that they chip, crack, and break apart more easily. Chemical weathering happens to rocks all over the earth's surface. Chemical changes work together with physical changes to weather and erode the earth's surface.

Evidence of a chemical change A chemical change makes a substance that wasn't there before. There may be clues that a chemical reaction took place, such as light, heat, color change, gas production, odor, or sound.

Evidence of Physical changes The starting and ending materials of a physical change are the same, even though they may look different. Any change in phase, for example, can be reversed. Ice can melt to form water and water can freeze to form ice. Usually only physical changes can be reversed.

Physical or chemical change- exit ticket When you freeze water ( ) Casting silver in a mold ( ) When you burn wood in your fireplace ( ) When iron (FE) rusts ( ) Melting a sugar cube ( ) When you step on a can and crush it ( ) When you cook an egg ( ) Solid iodine evaporating into a purple gas ( ) Taking an antacid to neutralize stomach acid ( )