Caroline left an ice cube on the kitchen counter. An hour later, she notices that the ice has changed. What evidence would Caroline have observed that shows a physical change has occurred? a) The ice melted to form a liquid. b) The ice is now colder. c) The ice melted to form a solid. d) The ice is now clear.
a) The ice melted to form a liquid.
A student placed 50 mL of vinegar in a glass bowl. She added 5 old pennies to the bowl. After 20 minutes, the student removed the pennies from the bowl and observed that the vinegar in the bowl had turned a shade of light brown, and the pennies were smooth and shiny. What type of change did the student observe? a) a change in color and shape b) a change of shape and state c) a change of color and texture d) a change of texture and state
c) a change of color and texture