what happens when two substances with different temperatures come into contact?
When two substances with different temperatures come into contact, energy transfer occurs between them until they reach thermal equilibrium, which is when they reach the same temperature. The energy transfer can happen in two ways:
1. Heat transfer through conduction: In conduction, the hotter substance transfers its thermal energy to the colder substance by direct contact. The faster-moving particles in the hotter substance collide with the slower-moving particles in the colder substance, transferring kinetic energy and increasing the temperature of the colder substance.
2. Heat transfer through convection or convection currents: This occurs when the substances are in a liquid or gas form. The warmer substance's particles are less dense, causing them to rise while the cooler substance's denser particles sink. This creates a continuous circulation or convection currents that transfer heat from the hotter substance to the colder substance.
Overall, as the energy transfer continues, the substances approach the same temperature, resulting in a thermal equilibrium where both substances are at the same average kinetic energy level.