Physical changes
What is the main difference between a physical and a chemical change
In a physical change, the material remains the same substance. A chemical change creates a new substance.
What must happen during a chemical change?
A new substance with different properties must form.
Name one possible sign of a chemical change.
Color change, gas production, temperature change, odor change, or a new substance forming.
A sheet of paper is torn into small pieces. What type of change occurred?
Physical change
What gas is already dissolved in Coke?
Carbon dioxide
A branch breaks into two pieces. Why is this a physical change?
The pieces are still wood. Only their size and shape changed.
Copper slowly turns green after being exposed to air and moisture. What type of change occurred?
A chemical change because a new green substance formed.
Two clear liquids are mixed, and the mixture becomes warmer. What evidence was observed?
A temperature change.
Baking soda and vinegar bubble when they are combined. What evidence did students observe?
Gas production and the formation of new substances.
Why do Mentos cause the carbon dioxide to escape quickly?
The rough Mentos surface provides many places for bubbles to form.
An ice cube melts into liquid water. What type of change occurred?
A physical change because it is still water
Wood burns and turns into ash. Why is this a chemical change?
New substances, including ash and gases, formed.
Why is using more than one piece of evidence helpful?
One sign alone may have another cause and may not prove that a new substance formed.
A material changes color during an investigation. Does the color change alone prove that a chemical change occurred?
No. Scientists should gather additional evidence.
Does the dramatic eruption prove that a chemical change occurred?
No. A dramatic event does not automatically mean a new substance formed.