Joe hung 2 identical metal cups, Y and Z, from a horizontal rod. A lighted candle was then placed directly under cup Y as shown below.
After a few minutes, Joe observed that the rod moved with cup Y moving up and cup Z moving down.
a. Joe explained that cup Y moved up because it had expanded and became lighter. What is wrong with his explanation?
b. Explain what caused cup Y to move up.
Source: Peiying Primary
ChiefKiasu
Its hard to read so I decided expanded the picture and this is the text:
a. Joe explained that cup Y moved up because it had expanded and became lighter. What is wrong with his explanation?
Ans: The answer is wrong because the cups have the same mass even if one is hotter than the other.
b. Explain what caused cup Y to move up.
Ans: Cup Y went up because of the hotter air inside the cup. The heated air in cup Y is lighter than the cooler air in cup Z.
teohyuquan
Thank you! 😄
I understand now☺️
Sorry for the bad quality photo
