Look at the picture. This is my family. My grandfather’s name is Nick Hand. My grandmother’s name is Mary Hand. My father’s name is Jim Hand. My mother’s name is Helen Hand. Jim and Helen are my parents. I have a sister. Her name is Kate Hand. My name is Tom Hand. I am ten, my sister is eight.

阅读短文内容，回答下列问题。

小题1:How old is Tom Hand?

小题2:Is Kate Tom’s sister?

小题3:Is Helen Hand his grandmother?

小题4:What’s his grandmother’s name?

小题5:Is Jim Hand his brother?

如图所示，曹冲称象的故事发生在距今1800年以前，从物理学研究方法来看，使用的是______法；而从物理原理来看，是利用______．