大気圧 https://hirakawatblog.com/%e7%89%a9%e7%90%86%e5%9f%ba%e7%a4%8e%e2%91%b1%e3%80%80%e5%a4%a7%e6%b0%97%e5%9c%a7%e3%83%bb%e6%b0%b4%e5%9c%a7%e3%80%80%ef%bd%9e%e6%b5%81%e4%bd%93%e3%81%8c%e5%8f%8a%e3%81%bc%e3%81%99%e5%9c%a7%e5%8a%9b/%e5%a4%a7%e6%b0%97%e5%9c%a7