Test Corrections: topic Name AP Physics 2 Submitted on what date?

Major claim (question #) Include a diagram or picture that illustrates the correct physics Provide a succinct and accurate caption(<30 words) with implications Caption goes here Cite your source here

Major topic NOT TRUE BECAUSE… Wrong answer 1 Provide brief physics-based explanation why this response is incorrect Wrong answer 2 Wrong answer 3 Question Answers Correct answer indicated with asterisk * and bold font

Test Corrections: Thermodynamics Sam Pull AP Physics 2 Submitted 12 October 2015

Conduction transmits energy when molecules with different amounts of kinetic energy collide (question 4) Particles with high kinetic energy collide with and transfer energy to particles with low kinetic energy. The process continues until molecules of a substance have, on average, the same kinetic energy. Source: https://ihome21.kennesaw.edu/new/img/thermal/conduction.jpg

Thermal conduction NOT TRUE BECAUSE… Higher energy molecules will, on average, rise to the top. Objects “rise to the top” when they have less mass per unit area (i.e., are less dense) than the fluid around them. Someone might pick this answer if they confused “higher energy molecules” with “less dense substances” in the context of convection. The hot molecules provide thermal radiation that is then absorbed by colder molecules. Molecules themselves are not ‘hot’. Thermal energy is a fluid that flows from high concentration (hot areas) to low concentration (cold areas). Thermal energy is NOT a fluid, however much we read about it ‘flowing’. We model it as a fluid because the analogy is useful in many contexts (e.g., flowing from areas of high temperature to low temperature). Question 4: “When one end of a cold metal spoon is placed upright in a cup of hot cocoa, the other end eventually gets warmer. On the scale of the molecules of the spoon, which of the following is the primary explanation of this phenomenon?” Higher energy molecules will, on average, rise to the top. The hot molecules provide thermal radiation that is then absorbed by colder molecules. *Higher-energy molecules hit lower-energy molecules and, on average, tend to reduce the difference in temperature between the ends of the spoon. Thermal energy is a fluid that flows from high concentration (hot areas) to low concentration (cold areas).