You must identify the example as a physical or chemical change and explain why you came to that conclusion. (EX: The Statue of Liberty changing color over time is due to a chemical change. One sign of a chemical change is color change. Due to the color changing from copper to green, I can conclude a chemical change occurred on the surface of the Statue of Liberty) You may not use the Statue of Liberty example I shared. You will turn in a presentation including 1 example of physical, and 1 example of chemical changes unless you choose to do 2 of each for extra credit.

Question

WRITE IN A COMPLETE SENTENCE THAT A 4TH GRADER CAN UNDERSTAND YOU AND SHOW TWO EXAMPLES FOR EACH CHEMICAL CHANGE AND PHYSICAL CHANGE

Answer 1

Examples of Physical and Chemical Changes

Physical Change

Example 1: Melting Ice
When ice melts into water, it is a physical change because the ice (solid) changes to water (liquid), but it is still made of the same substance: H₂O. If you freeze the water again, it will turn back into ice, which shows it hasn’t changed its chemical makeup.

Example 2: Breaking a Glass
When a glass tumbler breaks into pieces, this is a physical change. The glass is still glass, just in smaller pieces. You can put it back together, and it will still be the same material.

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Chemical Change

Example 1: Rusting Metal
When iron sits in water and air for a long time, it can turn into rust. This is a chemical change because the iron reacts with oxygen and moisture to form a new substance called rust (iron oxide). You can’t turn rust back into iron easily, which shows that a chemical change took place.

Example 2: Baking Bread
When you bake bread, the ingredients combine and change into a new product: bread. This is a chemical change because the heat causes the flour and other ingredients to go through a chemical reaction to create something new that smells and tastes different from the raw ingredients. Once baked, you can’t turn the bread back into its original ingredients.