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Who was Typhoid Mary?

Mary Mallon lived in New York about 100 years ago, and worked as a cook. It seemed that every family she worked for suffered an outbreak of typhoid fever! The Dept. of Public Health found that she harbored the bacteria salmonella typhi, which causes typhoid fever. Even though there were no antibiotics in those days, doctors did know how to culture ...

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WhowasTyphoidMary
Physics

The Coriolis Effect

The Earth, rotating at about 1000 miles per hour (1,609 km/hr), influences the flow of air and water on its surface. We call this the Coriolis Effect, named after French scientist Gaspard Coriolis, ... Continue reading

Coriolis
Geology

Arctic Carbon a Potential Wild Card in Climate Change Scenarios

The Arctic Ocean receives about 10 percent of Earth's river water and with it some 25 teragrams [28 million tons] per year of dissolved organic carbon that had been held in far northern bogs and other ... Continue reading

ArcticCarbon
Geology

The World's Biggest Popsicle

Stored in a commercial freezer in France, along with quite a lot of frozen meat and cheese, is about 15 kilometers' worth of ice cores, taken from glaciers in Greenland and Antarctica. Each giant ... Continue reading

TheWorldsBiggestPopsicle
Chemistry

Radon, A Rare Element

To the best of our knowledge, the entire universe is constructed from just over a hundred different types of building blocks called atoms. Each has its own characteristic properties, and while there ... Continue reading

RadonARareElement

Why Do We Call It A 'Vaccination?'

VaccinationSmallpox 'vaccinations' are in the news nowadays. What is smallpox and what is a vaccination? Smallpox is one of the oldest and most horrible diseases afflicting the human family. In the past, it killed twenty to sixty percent of victims, and left the survivors with disfiguring scars from the rash.

Early on people realized that survivors of smallpox were immune to further attacks. Over a hundred years before our present form of vaccination, a practice called 'variolation' was used, beginning in China and Asia and reaching Europe by the beginning of the 18th century. Variolation consisted of applying the pus or ground scabs from a patient who had a mild case of smallpox (also called variola, hence the name) to a scratch in the skin. This system wasn't very good: two or three percent of variolated people died of smallpox. But it was better than the 20-60 percent who might die in an epidemic. By the 18th century, people had noticed that those who had had a milder disease called cowpox were also immune from smallpox. Milkmaids often caught it from their cows.

So in the late 18th century, Edward Jenner invented the practice we now know as vaccination, so called from 'vaca', the latin word for 'cow'. Patients were innoculated with material from cowpox lesions, which is much safer than variolation because cowpox is a milder illness. Today, most adults over the age of 35 have a small round scar on their upper arm where they were vaccinated as children.