Today I learned taht Earth formed 4.6 billion years ago, and that inside Earth there are 4 different parts; inner core, outer core, mental and crust. Looking around Museum of Natural History I was able to understand how Earth began and how universe was formed. I was suprised to know that human's history is only 5 minutes if we look at the Earth's histry as 24 hours.I learned taht 'eras' of Earth for teh first time so it was little bit difficult. Now I can memorize that there are precambrian, paleozoic, mezoic, and cenozoic eras. I was very intresting to know that people deteriine how 'smart' a dinosaur is by their brain size. I was also fun to learn that stegosaurus's plates are not actually sharp, and is only for ohters to think taht it is sharp. I was pround to know taht Korea had advanced technology on astronmy.