Why milk sours is chemical change ?

How could a student test the effect of removing heat from a gas that is stored in a sealed container? what must occur in order for matter to change states?

The famous scientist galileo galilei did several experiments with sloping planes, which he rolled metal balls down so that he could study motion. by changing the slope, he could study how the speed at which the ball rolled was affected. what was the independent variable in galileo's experiment? a. the speed of the ball b. the slope of the plane c. whether the ball moved d. what the ball was made of

In science class richard learns that a substance has a boiling point of 230 fahrenheit his teacher ask him to convert this temperature to degrees celsius what is the boiling point of his substance in degrees celsius