Skip to main content
Back

Temperature, Heat, and Thermal Expansion

Control buttons has been changed to "navigation" mode.
1/20
  • What is temperature?

    Temperature is a measure of the warmth or coldness of an object, proportional to the average translational kinetic energy per particle in a substance.

  • How does temperature relate to particle motion in solids, liquids, and gases?

    In gases, temperature reflects how fast particles bounce; in liquids, how fast they slide and jiggle; in solids, how fast they vibrate in place.

  • How does a thermometer measure temperature?

    By the expansion or contraction of a liquid (mercury or alcohol) until thermal equilibrium is reached with the object.

  • What is heat in physics?

    Heat is internal energy transferred between objects due to a temperature difference, flowing from higher to lower temperature until equilibrium.

  • What is the difference between temperature and thermal energy?

    Temperature is average kinetic energy per particle; thermal energy depends on total kinetic energy and amount of substance.

  • What units measure quantity of heat?

    Heat is measured in joules or calories; 4.19 joules equals 1 calorie.

  • What is specific heat capacity?

    Specific heat capacity is the heat required to raise the temperature of 1 gram of a substance by 1ºC, indicating thermal inertia.

  • Why does water have a high specific heat capacity?

    Water absorbs energy in various ways, including molecular vibrations and rotations, allowing it to store more heat without large temperature changes.

  • How does specific heat capacity affect climate?

    Water's high specific heat moderates climate by storing and releasing heat slowly, influencing coastal temperatures and weather patterns.

  • What causes thermal expansion?

    When temperature rises, molecules jiggle faster and move farther apart, causing most substances to expand.

  • Why do railroad tracks buckle in summer?

    Railroad tracks expand due to heat; if expansion joints are insufficient, the tracks can buckle.

  • What is a bimetallic strip and its use?

    A strip of two metals with different expansion rates that bends with temperature changes, used in thermostats and switches.

  • Why should telephone lines be strung with slack in summer?

    Because lines expand and sag in heat; without slack, they may snap in cold when contracting.

  • How does thermal expansion differ between liquids and solids?

    Liquids generally expand more than solids when heated.

  • Why does water expand when it freezes?

    Ice forms open-structured crystals that increase volume, making ice less dense than liquid water.

  • What happens to water volume between 0ºC and 4ºC?

    Water contracts as ice crystals collapse until 4ºC, then expands as molecular motion increases.

  • Why does ice float on water?

    Because ice is less dense than water due to its expanded crystal structure.

  • What is thermal equilibrium?

    The state when two objects in contact reach the same average kinetic energy per particle and no net heat flows.

  • How does heat flow between objects of different temperatures?

    Heat flows spontaneously from the higher temperature object to the lower temperature one until equilibrium.

  • What is the calorie in terms of heat energy?

    The amount of heat needed to raise the temperature of 1 gram of water by 1ºC, equal to 4.19 joules.