Should we really be drinking eight glasses of water a day?

Should we really be drinking eight glasses of water a day? There is lots of advice around, but how do you know when you’ve had enough or if you’re drinking too much? With help from Professor Stanley Goldfarb from the University of Pennsylvania, Wesley Stephenson finds out.
Also, why do most people in America who own a gun now say it’s for self-protection, whereas 20 years ago it was for sport or hunting? The data shows that crime has declined significantly, so what are people really scared of, and is it rational to respond in this way?

Also, can crowdmapping be an effective tool to tackle hate crime and political violence? And has the Mormon Tabernacle Choir’s decision to perform at Donald Trump’s presidential inauguration ceremony divided Mormon communities?

(Image: Hand holding a glass of water. Credit: Charlotte Ball/PA Wire)