Sian wants to measure the number of seconds that it takes for the contents of a beaker to change from clear to purple. which of these tools should she use for this purpose? 1 an electronic balance 2 a stopwatch 3 a barometer 4 a graduated cylinder

Answer : The correct option is, (2) a stopwatch

Explanation :

Electronic balance : It is used to measure the amount of substance.

Stopwatch : It is used to measure the time.

Barometer : It is used to measure the pressure.

Graduated cylinder : It is used to measure the volume.

If sian wants to measure the number of seconds that it takes for the contents of a beaker to change from clear to purple then the tool she use for this purpose is, a stopwatch.

Hence, the correct option is, (2) a stopwatch

explanation:

earth's surface is mainly heated by the absorption of infrared radiation from the sun.

evaporation occurs because molecules in liquid water are warmed ( usually by the sun) and vibrate quicker, becoming less dense and rise.

condensation occurs because molecules in water vapor are cooled and therefore vibrate more slowly thus becoming more dense and eventually fall to earth.

lines of equal barometric pressure on a weather map are called: isobars : lines of equal temp on a weather map are called: isotherms.​

b

explanation: