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Charmed,
I?m Sure.
Between the 1200s and 1700s, the bubonic plague regularly
struck the cities of Europe and killed an estimated
20 percent of the population. Because no one knew
what caused the plague?or more importantly,
how to prevent or cure it?people relied on potions
and magic charms. Pretend a mysterious illness has
hit your school. Decide what its symptoms are, and
give it a name. Then, keeping the disease?s
symptoms in mind, design a magic charm that people
can wear for protection.
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Beneficial Bacteria Scrapbook.
We often hear about disease-causing bacteria and their
effects. Yet, a significant number of bacteria are
helpful to humans and the environment. Make a scrapbook
about good bacteria. Collect articles and ads from
newspapers or magazines. Include photos (or draw pictures)
and add information about where the bacteria can be
found?in the environment, lab, food, or human
body.
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Microbe Math.
Bacteria make more of themselves using a fast and
simple process called binary fission. First the cell
makes a copy of its DNA molecule. Then it stretches
into an elongated shape, narrows in the middle, and
finally splits in half. Some bacteria repeat this
process several times an hour. Suppose a bacteria
cell divides every 15 minutes. How many cells would
be created from just one starter cell in a 24-hour
day?
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Defend!
To harm us, a pathogenic bacterium has to get inside
a body first. Then it must outmaneuver the immune
system. Most bacterial invasions end quickly, thanks
to the body?s natural defenses. But it?s
best not to undergo a bacterial invasion at all. Cuts
are one way a pathogenic bacterium can enter. Research
other possible methods of entry, and make a drawing
of at least one.
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Plan Ahead.
Most places in the world have outbreaks of bacterial
illnesses. Most illnesses vary, depending on location.
In recent years, cholera (Vibrio cholerae) has cropped
up in some parts of South America and Lyme disease
(Borrelia burgdorferi) has plagued parts of North
America. Both continents have also had outbreaks of
food poisoning (Escherichia coli). Investigate these
three illnesses, and create information sheets that
explain how they can be avoided.
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I Just Can?t Resist.
Most antibiotics are broad-spectrum, meaning they
knock out many different types of bacteria. This also
means that they can?t tell good bacteria from
bad. We?ve had antibiotic medicines for a little
over half a century, but in that time some bacteria
have developed resistance to just about every antibiotic
invented. The overuse of antibiotics in recent years
is also causing problems. Investigate antibiotic resistance,
and then create a public-health campaign for your
school that includes recommendations for fighting
this threat.
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Dine on a Bacterial Culture.
Many of the yogurt brands on the market today contain
living bacteria?the good kind. (Look for the
words ?live yogurt culture,? ?acidophilus,?
or ?lactobacillus? on the label.) Grow
your own container of yogurt with 8 ounces of milk
and a teaspoon of starter yogurt. Here?s how:
Once the milk has reached room temperature, stir in
a teaspoon of living-bacteria yogurt. Pour the mixture
into a clean plastic or paper cup, and put it in a
shoebox that?s lined with a sheet of rubber
foam or a few handfuls of polystyrene foam pellets.
Put the shoebox cover on, drape a clean dishtowel
over the box, and place it in a sunny window or near
a radiator. Wait at least 24 hours. Then grab a spoon
and dig in!
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Lunch Time.
Outdoor meals are ideal breeding grounds for bacteria.
If food is not handled carefully, food poisoning can
result. Research Escherichia coli (E. coli), Salmonella
enteriditis, and shigella, three types of bacteria
responsible for food poisoning. Then plan an outdoor
class picnic when the weather is warm. What should
you serve? How should the food be prepared and kept
to avoid food poisoning?
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