All posts by Paula Fogarty

Waterborne Disease/Poop Chronicles, Part One

Students are interested in disease, especially the diseases with a high yuck factor! Waterborne diseases fill the bill. It’s easy to engage kids with this, but it’s also a very sound idea because this encompasses lots of important topics: sanitation, hygiene, the digestive system, water treatment, microbiology, etc. You can even look at history and warfare from a perspective of disease. So here are some pictures and a mini-lecture to get started.  (I also mentioned one or two diseases that are not waterborne, just because their mode of transmission is interesting!)

In ancient history, before settlements were established, the world’s human population lived in small tribal groups that were nomadic. They hunted and gathered in one area till game ran low, then they moved on. And as they moved they left their wastes behind. A good idea, since human wastes can harbor disease!

But about 10,000 years ago people started planting seeds and domesticating livestock. This was a huge change that we call the first agricultural revolution, and it allowed humans to settle in one place.  In time farmers became successful enough that they had excess grain that could be stored, encouraging the presence of rodents, which in turn carried diseases such as smallpox that could then make the jump into humans.

poop chron screen shot ag with irrigationpoop chron screen shot mice

Isolated settlements sprang up, and they were usually located on a river or stream so people had plenty of water for drinking and for irrigation.  And rivers were also used as handy places to dispose of wastes.

Over time the settlements grew into teeming cities and wastes built up, harboring microbes that caused outbreaks of epidemics.  Merchants plied their trades, moving from marketplace to marketplace, bringing diseases with them.

As the human population grew, settlements sprang up in the empty spaces between cities.  At the point in time when settlements began to be located about two weeks’ walk apart, smallpox, which had an incubation period of fourteen days, spread in epidemics.

Centuries passed, till finally a phenomenal change occurred in human history, a change in which machines were developed that could do the work of humans.  This, of course, was the Industrial Revolution.  Threshing machines and other inventions could do the work previously requiring many human hands, and the out-of-work farm workers moved into the cities, where newly-built factories needed laborers.

poop chron screen shot working conditions

Working conditions there were often miserable:  long hours (dawn to dark), dusty, dark factories that were unsafe and closed in, no vacation, no sick-leave.  Child labor was common, even in the mines.

Living conditions for the poor were crowded and unhealthy, with several families living in one room of a tenement building.  The air of the cities was dark with smoke and soot and the streets were filled with trash and garbage.  Slaughter houses with blood, dung and flies were built in the cities, sometimes located next to schools.  Rivers carried chemicals and raw sewage floating on the surface.  Drinking water was accessed in public wells and was also taken directly from the river, bottled and sold untreated.

As shown in this fantastical newspaper cartoon of the 1800’s, people were starting to be disgusted by the appearance of the water, though they didn’t connect disease to the organisms that they could see in it with their microscopes that were then popular as toys or curiosities.

poop chron screen shot shocking water

Outdoor privies were used for human wastes and the matter collected in storage holes called cesspools, which were sometimes lined with brick or stone, but were sometimes just bare dirt.

It is estimated that by the 1850’s the city of London had 20,000 outdoor privies.  In the home, for convenience, people used chamber pots.  In the mornings, housewives tidied up by emptying the contents out the windows of the upper stories.  Look out below!

poop chron screen shot priviespoop chron screen shot chamber pots

These were the conditions when a cholera epidemic swept through the city of London in 1854.  Cholera was, and still is, a fearsome disease.  A victim can be healthy in the morning and dead by noon!  It is characterized by nausea and vomiting, cramps, and severe diarrhea.  Cholera sometimes breaks out, even today, where people are crowded together in conditions such as are found in many refugee camps, after a war or severe flooding or other natural disasters.  Medical workers in these places often put the patients on cots such as the ones pictured, with buckets under the holes to facilitate clean-up of the diarrhea.  So much fluid is lost from the body that vital minerals, needed for the heart to function, are carried away with the fluid, and the victims die of heart failure.  In recent years it has been discovered that clean water mixed with a little sugar and table salt, given by mouth or intravenously, can spell the difference between life and death!

poop chron screen shot cholera cots

This brings us to London and the cholera epidemic of 1854.  In one area of the city hundreds of people were infected and as many as 50% of the patients died.  Queen Victoria summoned Dr. John Snow,  a famous person in epidemiology even now, and directed that he stop the epidemic.  This was a tall order since the cause of cholera and the means of transmission weren’t known then.  In fact there was little understanding of diseases and germs at that time.poop chron screen shot the queen

Watch for Poop Chronicles, Part Two, coming next week, for the rest of the story, and for a fascinating activity modeling London’s cholera epidemic and asking students to figure out how to stop its spread.

 

 

No infringement of  copyright is intended with the use of these pictures.  Owners of copyrights can request removal and we will comply promptly.

 

Exciting Cell Projects for Your Students

Cells and Cell Projects
To introduce the cell or for review, you can’t beat manipulatives! Pictures of organelles that can be placed on a picture of an “empty” cell, (just the membrane or membrane and cell wall with cytoplasm and maybe ribosomes) can be a very effective strategy to engage students.
Have students try these:

  • Assemble and compare the plant cell and the animal cell.
  • Pass out the organelles.  Call out the name of an organelle and have the student who holds it bring it to the board and explain its function before adding it to the cell.
  • Have students choose the relevant organelles and use them to explain and enact an overview of protein synthesis.

Cell Projects                                                                                                                                                             Cell models made of cake, cookies, Jello, legos, styrofoam, cardboard, cloth.     One student, a dedicated skater, even made his model using bits of hardware from an old skateboard, housed inside a small metal box that originally held skateboard bearings!  The key to the organelles was pasted inside the lid.  I ran into him in a cafe 15 years later, and he told me he still remembered that model!
So it seems that these projects are time well spent. But after retiring, I wondered. If the high school students have made cell models in middle school and a brief review is sufficient to bring it all back, or if you want to present your class with more of a challenge, then maybe it’s time to up the ante.
How about going beyond the generic cell model and asking /assigning students to create a model of a specific kind of cell? Many cells are fascinating in their own right. With around 200 cell types in the human body, there’s such a rich assortment to choose from! But some students might prefer some type of plant cell or even a single-celled organism. You’ll see some ideas on the next page.

Cell Project—High School Level                                                                                                                        Make a choice from the lists below for research and a presentation. Make a poster to help as you present. Differentiated Cells These cells are specialized cell types that perform special functions. General requirements and questions to consider: Compare and contrast the specific cell(s) you chose to the generic plant or animal cell studied in class. What important function does your cell perform for the organism it is part of? How does the structure of your cell relate to its function? Are any of your cell’s organelles absent or present in extremely large numbers? To what effect? How does your cell function to help maintain homeostasis? Explain. Give special attention to any interactions between cell pairs. Do the cell pairs act together to achieve balance for the organism they are part of? What might happen if the cells’ interaction gets out of balance? Do the cells help each other in some way?                                                                                                                                           Cell Choices:

  • a cardiac muscle cell
  • a striated muscle cell
  • osteocyte/osteoblast/osteoclast
  • neuron and glial cell
  • sperm cell and Sertoli cell
  • red blood cell and platelet
  • vessel element
  • sieve tube member/companion cell

Cell & Protein Choices:

  • adipose (fat) cell and leptin
  • plasma cell and antibodies
  • chief cell and pepsin
  • red blood cell and hemoglobin
  • alpha cell of the pancreas and glucagon
  • beta cell of the pancreas and insulin