You need 8 glasses of water a day
They say: The human body needs water. It needs a lot of water: a minimum of 8 glasses of water a day to be healthy.
Why they are wrong: It is true that experts say we need 8 cups of water a day. A lot of people hear this and think that ‘cups’ means the same thing as ‘glasses’. Keep in mind that this advice comes from doctors. Doctors are specific, especially when it comes to measurements. If they say cups, they mean cups: that is, 250 ml. The glasses you use to drink water from can be anywhere up to half a litre. The advice should read: you need about 2 litres of water in a day.
Another reason they are wrong: It’s not 8 cups of water in addition to whatever else you eat or drink in a day. If you drink 3 cups of juice in a day, you don’t need to drink 8 glasses of water, you would only need 5. The advice should read that you need 8 cups of liquid a day. Though, for optimal health, those liquids should be something healthy, like water. Coffee and alcohol would not be good choices, as too much of either of them is quite bad for you.
Yet another reason they are wrong: Humans get liquid from other places than drinking it straight. Most of the food we eat has at least some water content. Fruit and vegetables tend to have large portions of water.
We only use 10 percent of our brains.
They say: Human beings have so much untapped potential: we only use 10 percent of our brains, think what we could accomplish if used all of them. Certainly, psychic powers must lie within the other 90 percent.
Why they are wrong: There are no such thing as psychic powers, but that’s a topic for another Factoid. The misconception in this myth lies in the fact that people think that the other 90 percent is completely unused. A better statement of this myth would be that humans usually only use about 10 percent of their brains at a time. Different parts of the brain are active during different activities. Composing a Factoid uses different parts of the brain than does solving a complex math problem, watching a movie, or trying to remember a loved one’s birthday. Over the course of a day, most people will use most of their brains.
Additional Details:
The water myth: http://www.snopes.com/medical/myths/8glasses.asp
Human potential: http://www.snopes.com/science/stats/10percent.asp
