1. When a colder object is placed in contact with a warmer object, ____________________.
a. the particles of matter exchange places
b. the particles in the colder object slow down while they cool down the warmer object
c. the particles in the warmer object slow down while they warm up the colder object
d. the objects exchange phone numbers
2. Which of the following is not a process that transfers thermal energy? *
a. Cooking soup on the stovetop.
b. Baking a cake in the oven.
c. Warm air rising off a baseboard heater.
d. Ice kept in an insulated container.
1. The correct answer is c. the particles in the warmer object slow down while they warm up the colder object.
Explanation: When a colder object is placed in contact with a warmer object, heat energy is transferred from the warmer object to the colder object. This transfer occurs due to the random motion of particles. The particles in the warmer object have higher kinetic energy and faster motion compared to the particles in the colder object. As a result, some of the energy is transferred from the warmer object to the colder object, causing the particles in the warmer object to slow down while they warm up the colder object. This process continues until the two objects reach thermal equilibrium, where they have equal temperatures and there is no further net transfer of heat energy.
To understand this concept, you can also perform a simple experiment. Place a metal spoon in a cup of hot water. Initially, the spoon will feel cold. However, over time, it will start to feel warm as the heat energy from the hot water is transferred to the spoon.
2. The correct answer is d. Ice kept in an insulated container.
Explanation: Thermal energy is the transfer of heat energy from a warmer object to a cooler object. The other options mentioned (cooking soup on the stovetop, baking a cake in the oven, warm air rising off a baseboard heater) all involve processes that transfer thermal energy.
Cooking soup on the stove involves the transfer of heat from the stove (a hotter object) to the soup (a cooler object) through conduction. Baking a cake in the oven involves the transfer of heat from the oven (a hotter object) to the cake (a cooler object) through radiation and convection. Warm air rising off a baseboard heater involves the transfer of heat from the heater (a hotter object) to the air (a cooler object) through convection.
On the other hand, ice kept in an insulated container does not involve any transfer of thermal energy. The insulation helps to prevent the exchange of heat energy between the ice and the surroundings, thereby keeping the ice cold for a longer period. This process is often used to keep items frozen, such as in coolers or refrigerators.