A student tears one sheet of paper into strips for a collage. The strips are smaller and have ragged edges, but each strip is still paper. Is this a physical or chemical change?

A small paper scrap is burned safely by a teacher. Heat, smoke, and gray ash are left where the paper was. Is this a physical or chemical change?

An ice cube sits in a cup and melts into clear liquid water. No gas, smell, or color change is observed. Is this a physical or chemical change?

A carton of milk is left warm for too long. Later, the milk smells sour and has lumpy curds. Is this a physical or chemical change?

A teaspoon of sugar is stirred into water until the grains can no longer be seen. The sweet solution can leave sugar crystals after the water evaporates. Is the change physical or chemical?

A clean iron nail is left outside in damp air. After several days, reddish-brown rust covers part of the nail. Is this a physical or chemical change?

Salt is stirred into warm water until it cannot be seen. A classmate says the salt changed into a new substance. Which observation best shows that the salt is still salt?

A candle is warmed so that some solid wax becomes liquid wax. When the wax cools, it hardens again. Is this a physical or chemical change?

A carpenter saws a board into sawdust and shorter pieces. The sawdust still has the color and smell of wood. Is this a physical or chemical change?

During a campfire, a dry stick gives off heat and light. After cooling, gray ash and smoke remain instead of the original wood. What do these observations show?

A banana slice is left on a plate. After a while, the cut surface turns brown and develops a different smell. What does this evidence show?

A pad of steel wool is left damp overnight. The next day it has reddish flakes and feels slightly warm. What does this evidence show?

An egg white is heated in a pan. It changes from clear and runny to white and firm, and cooling does not make it clear again. What does this evidence show?

Cloudy water is poured through a coffee filter. Brown mud stays in the filter, and clearer water drips through. What does this evidence show about the muddy water?

A dry tray contains gravel and fine sand. When the tray is shaken over a screen, sand falls through while gravel stays on top. What does this evidence show?

A tray of melted ice is placed back in a freezer and becomes solid ice again. What does this reversibility show about the change?

Salt water is left in a shallow dish. After the water evaporates, white salt remains and can be collected. What does this show about the change?

A piece of chalk snaps into chunks. The chunks cannot be made back into one smooth stick by hand. What does that tell you about the change?

Toast is left in the toaster too long and turns black with a burnt smell. Scraping cannot make it fresh bread again. What does this tell you about the change?

A tray contains sand and iron filings. After a magnet is passed nearby, the iron filings are removed from the sand. What does this show about the tray's contents?