Temperature and Measurement
What does temperature measure?
The average kinetic energy of the particles in a substance.
What is kinetic energy?
The energy an object has because of its motion.
What are the three common temperature scales?
Celsius, Fahrenheit, and Kelvin.
Which temperature scale would you most commonly see on a weather report in the United States?
Fahrenheit
Define temperature.
Temperature is a measure of the average kinetic energy of particles in a substance.
What happens to the average kinetic energy of particles when temperature increases?
The average kinetic energy increases because the particles move faster.
True or False: Kinetic energy depends only on mass.
False. Kinetic energy depends on both mass and speed.
Which temperature scale is commonly used by physicists?
Kelvin.
Water freezes at what temperature on the Celsius scale?
0°C
Define kinetic energy.
The energy an object has because of its motion.
Two samples of the same substance have different temperatures.
Which sample has particles with greater average kinetic energy?
The sample with the higher temperature.
If the temperature of a substance increases, what happens to the average motion of its particles?
The particles move faster on average, meaning their average kinetic energy increases.
What is absolute zero?
Absolute zero is 0 K, the theoretical lowest possible temperature, where particles have their minimum possible thermal motion.
Water boils at what temperature on the Celsius scale at standard atmospheric pressure?
100°C
What is thermal energy?
The total energy associated with the motion and positions of particles in a substance.
A thermometer reads 25°C. What does this measurement tell you about the particles?
It tells you about the average kinetic energy of the particles; the particles have a specific average amount of kinetic energy associated with that temperature.
Which particles have greater average kinetic energy: particles in a 10°C sample or particles in a 50°C sample of the same substance?
The particles in the 50°C sample.
Why is Kelvin useful in science?
Kelvin begins at absolute zero and is directly related to the absolute temperature used in scientific calculations.
Which is colder: 0°C or 0 K?
0 K is much colder. 0 K is absolute zero, while 0°C is the freezing point of water.
What is the difference between temperature and thermal energy?
Temperature describes the average kinetic energy of particles, while thermal energy refers to the total energy associated with all the particles in a substance.
Explain the relationship between temperature and particle motion in one or two sentences.
Temperature is related to the average kinetic energy of particles. As temperature increases, particles generally move faster; as temperature decreases, they generally move more slowly.
Explain why increasing the temperature of a substance generally causes its particles to move faster.
Increasing temperature means increasing the average kinetic energy of the particles, so the particles move faster on average.
How does one degree Celsius compare with one kelvin?
They are the same size. A change of 1°C is equal to a change of 1 K.
A scientist measures a substance at 300 K. Is this temperature above or below 0°C? Explain.
Above 0°C. 300 K is approximately 27°C.
Explain how the particles in a hot substance compare with the particles in a cold substance.
Particles in the hotter substance have a greater average kinetic energy and generally move faster than particles in the colder substance.