A simple physics riddle that confused many people.
In the evening, our family was watching TV in the living room. Suddenly, my father smiled and said to me, "Xiao Ming, I want to ask you a few questions, and you need to answer quickly and accurately, how about it?" I am confident. I am a fifth-grade student. What questions can't I answer?
Dad asked, "Which one is heavier, one kilogram of cotton or one kilogram of iron?" I answered quickly, "of course iron is heavier." My mom and sister laughed. It seemed that my answer is wrong. Dad said to me again, "Be careful. I'm talking about one kilo of cotton and one kilo of iron, so they weigh the same. "
Dad asked again, "So, which one is heavier, one cubic meter of cotton or one cubic meter of iron?" This time I paid close attention to what my father said, and replied, "They weigh the same!" Everyone laughed again. I thought about it and suddenly I found myself answering the question wrong again. "This time, the iron is heavier."
Dad asked again, "Which volume is bigger, one kilogram of cotton or one kilogram of iron?" I have received humiliation twice and thought about the question. "The volume of cotton is bigger! The volume of one kilo of iron is very small, and one kilo of cotton has a big volume." Everyone listened and smiled with satisfaction.
Dad said, "No matter what the problem is, we should think carefully. The questions I just asked you are all very simple, but because you thought they are simple, you didn't answer them seriously. As a result, you answered wrong and got laughed at by others. "
I nodded and kept Dad's words in mind.
Photo source here.