Ideas

Period pain happens when the uterus contracts to shed its lining, triggered by hormone-like chemicals called prostaglandins. Why Before and during periods

A hydrogen bomb uses a fission explosion to compress and heat hydrogen isotopes until they fuse, releasing far more energy. Teller-Ulam design A fission

A switch connects devices within a network, while a router connects networks to each other and to the internet. Switch Connects devices within one local network (LAN).

Hong Kong is on Hong Kong Time (UTC+8) all year with no daylight saving. Time zone Hong Kong Time (HKT) is UTC+8 all year. Daylight saving None.

Costa Rica is a popular destination generally considered safe for tourists, though petty theft occurs. Check the current US State Department advisory before you go.