# Bad Science/Placebo/Background
## The Placebo Effect: Do You Believe Your Teacher?

Background Notes

### Caffeine

What’s another name for 3,7-dihydro-1,3,7-trimethyl-1H-purine-2,6,-dione? Yep, CAFFEINE. Caffeine is the most popular drug in the world, and we’ve all been known to try it at least once: in coffee, tea, cocoa, some soft drinks, some drugs… …and in the popular treat, chocolate!
The actual source of caffeine is the coffee bean, tealeaf, kola nut and cacao pod. Pure caffeine is odourless and has a bitter taste.
Caffeine is a central nervous system stimulant. In moderate doses, caffeine can:
* increase alertness and speed of reactions
* reduce memory
* reduce fine motor coordination (giving you shaky hands!)
* cause insomnia (sleepless nights!)
* cause headaches, nervousness and dizziness
Caffeine enters the bloodstream through the stomach and small intestine and starts to have its effects within fifteen minutes of ingestion. Once in the body, it takes about six hours for one half of the caffeine to be eliminated.
Why is caffeine said to be addictive? One way to tell if someone "can’t live without" that mocha latte or two shots of espresso is to take it away from them and see what happens.
Typical withdrawal symptoms associated with caffeine include throbbing headaches and aching muscles. These symptoms can occur within 24 hours after your last “dose” of coffee.
One study has said that the minimum consumption of caffeine for you to be labelled a coffee-addict is four cups of coffee per day. But it really depends on you! Some people, if they don’t get that one cup in the morning, just can’t function at all! In massive doses, caffeine is lethal. A fatal dose of caffeine has been calculated to be more than 10g. To get this dose, you’d need to drink 80-100 cups of coffee in one sitting - good news for coffee houses everywhere, but extremely difficult to do! Did you know?

### How Coffee was discovered…

“Legend has it that coffee was "discovered" around 850 AD in upper Egypt by a goat herded named Khaldi. One night, Khaldi's goats did not return home. When he found his goats, Khaldi saw them dancing around a shrub with red berries (coffee beans). After Khaldi tried some of the berries, he started to dance too. Khaldi spoke with some monks who used the berries to make a drink and....coffee was born!” (For further information see: http://faculty.washington.edu/chudler/caff.html)

### How to take a pulse

“The easiest place to take a pulse is at the wrist, whether it is your own or someone else’s. The fingers – not the thumb because the ball of the thumb has too strong a pulse of its own – should be lightly but firmly pressed over the radial artery. You’ll find it about 1 cm in from the thumb side of the wrist. Move your fingers around a little if you can’t find it right away; you will soon feel the gentle throbbing. Count the number of beats in 30 seconds, using a watch with a second hand to make sure you time it exactly, then multiply by two. A healthy pulse can be very variable. The average resting adult’s rate is 70 per minute but can range from 60-80; children have a higher rate and a baby’s may be 140. If active or excited, the pulse rate will increase.”
(From the book, How to Hold a Crocodile by the Diagram Group)

#### Longest time survived without a pulse

“The longest time a human has survived without a pulse in their vascular system is three days. Julie Mills (UK) was at the point of death from severe heart failure and myocarditis when, on 14 August 1998, cardiac surgeons at the John Radcliffe Hospital, Oxford, UK, used a non pulsatile blood pump (AB180) to support her for one week. Her heart recovered in this time and the pump was removed.”

#### Slowest heartbeat in a mammal

“The mammal that is presumed to have the slowest heartbeat of any warm–blooded animal is the blue whale (Balaenoptera musculus), with between four and eight beats per minute dependent on whether or not the whale is diving. By comparison the average adult human heart beats at 70 beats per minute. Blue whales also have the largest heart of any animal and their heartbeat can be heard up to 32 km (20 miles) away underwater.”
(From the Guinness World Records 2005: 50th Anniversary Edition