The term is used in chemistry, biology, and agronomy. PH translates the values of the concentration of the hydrogen ion into numbers between 0 and 14.

• Pure water corresponds to a pH of 7, which is neutral (neither acidic nor alkaline). 
• A pH less than 7 is co...

If there's a test coming up in the next 7 days, the recommended way to study: 3 to 4 sessions with spaces in between, instead of studying non-stop for 7 days.

This way, you study less, yet retain more for the day of the test.

Most adults function best after 7-9 hours of sleep a night.

When we get less than 7 hours, we’re impaired (to degrees that vary from person to person).  When sleep persistently falls below 6 hours per 24, we are at an increased risk of health problems