ScienceIQ.com

The Physics of Sandcastles

Give a plastic bucket and a shovel to a child, then turn her loose on a beach full of sand. She'll happily toil the day away building the sandcastle to end all sandcastles. It's pure fun. It's also serious physics. Sandcastles are built from grains - billions of tiny sharp-edged particles that rub and tumble together. The strength of a sandcastle ...

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Sandcastles
Biology

Word Power of the Very Young

Before they turn 2, most children have a vocabulary of about 50 words. From 1st to 5th grades, according to some estimates, their vocabulary increases by about 30,000 words. That's 20 words a day! How ... Continue reading

WordPowerChildren
Biology

Gestation Periods of Mammals

Gestation period is the time from fertilization to the actual birth in animals. In humans this period is 266 days or approximately 9 months. ... Continue reading

GestationPeriodsofMammals
Medicine

My Aching Back

The back is an intricate structure of bones, muscles, and other tissues that form the posterior part of the body’s trunk, from the neck to the pelvis. The centerpiece is the spinal column, which not ... Continue reading

MyAchingBack
Biology

Why Aren't Mice More Like Us?

The sequence of the human genome was published two years ago, and recently, the sequence of the mouse genome was published. Amazingly, 99% of mouse genes have a counterpart in people. So why are they ... Continue reading

Mice

Resistance is NOT Futile!

ResistanceisNOTFutileMaybe if you are a Star Trek heroine up against the Borg, 'resistance is futile.' But if you are a germ that makes people sick, resistance - to antibiotics - is not futile at all.

When penicillin began to be widely used over fifty years ago, it could kill most of the bacteria that made us sick. Such bacteria are called 'pathogens,' to distinguish them from the many bacteria that are harmless or even useful. Nowadays, many pathogens are 'resistant' to a lot of the antibiotics we use to combat them. They have evolved the ability to fight off the effects of the drugs, so the drugs cannot cure you. This can be very dangerous in hospitals, where drug-resistant pathogens can spread rapidly and kill many people.

How can bacteria evolve drug resistance so quickly? The genes for drug resistance are usually not carried as part of the regular chromosome, but on extra rings of DNA called plasmids. These can be passed on to the bacterial cell's descendants, and can also sometimes be passed around to any other bacteria that happen to be in the area, even those of other species. If a drug kills all the susceptible bacteria, any few that are resistant will be free to multiply without competition and take over the population. So we are involved in an 'arms race' between biologists and chemists inventing new antibiotics, and pathogens inventing new ways to resist them.