General Science, Module 1, A Brief History of Science

►Videos & resources for this module

This was a very interesting first module.  =)
We learned about different scientists from way back, up to more modern times.
In the beginning, they didn't always know why things were the way they were.  The Egyptians were known for their medicine, but most of it was trial and error.  (I sure wouldn't have wanted to be on the receiving end of the error!)  They usually didn't know why certain things helped heal.
The Egyptian doctors and inventors did collect a lot of facts, but historians don't consider them to be true scientists since they didn't use this knowledge to explain the world around them.

This module mentions over 30 scientists!  We learned that some scientists had wrong hypotheses but were believed because they were great scientists, but some who had correct hypotheses were rejected.  Some had writings that were banned (Copernicus), and some scientists were even put into prison! (Galileo)  Some died never knowing their hypothesis was eventually accepted.
"...no scientist's work should be supported because the person was great.  It should only be supported because the scientific evidence supports it!" (p. 9)
Eventually these ideas got straightened out, but in Module 2 we will learn that unbelief caused many deaths.  Most doctors didn't believe what Dr. Ignaz Semmelweis said -- that they should wash their hands before going to each new patient.  Some doctors came straight from the mortuary and went to examine new mothers!!!  This went on for 10 years after it was shown that thoroughly washing hands in a solution did cut down on the mortality rate in hospitals!  Semmelweis was eventually put into prison and died never knowing that doctors finally realized the truth.
People just do not want to accept anything new.

One thing I thought was rather interesting was the alchemists (see the word chemist?) who wanted to find a way to make gold our of lead.  That seems rather silly to us today, but back then they thought they could do it!  They also tried other substances, trying to make something of more value.
During this time, very little progress was made in the field of science.  The culture was just different then, and the "Roman Empire didn't mind inventions..., but had little use for the practice of explaining the world around us."  (p. 12)
"Scientific progress depends not only on scientists, but it also depends on government and culture." (p. 14)

Scientific progress had slowed down, but a lot scientific observations of things had been written down by monks.  These were written in large volumes that were eventually called encyclopedias.  =)
Both Arabs and Chinese also kept detailed records of their observations even though they didn't know at the time what they were seeing.  Later, scientists were able to read this information and know what had been seen!  This information was very helpful to the more modern scientists who had better tools and resources.  "Science progresses by building on the works of previous scientists." (p. 16)

Near the end of the Dark Ages, science began to pick up a little.  The Romans believed in many gods, and believed things happened on the whims of the gods.  We now know that it is God's laws of nature.
A man named Robert Grosseteste believed that the happenings in nature could be explained by laws.  He taught that the reason to experiment was not just to come up with great inventions, but to find the reason things happen the way they do.
He said that scientists should come up with an explanation for why events happened, then perform an experiment to test this explanation.  If the experiment didn't confirm the explanation, a new explanation was needed.  This led to what is now called the scientific method.  Hypotheses do not become theories until they are supported by the evidence of the experiment.  Eventually after years of testing, a theory might become a scientific law.


I have more kids in my science class this year, and it is fun!  =)
We learned about the scientists that contributed to the first inklings of knowledge of atoms.
An object that has atoms that are more densely packed together will sink through more dense liquids than an object with less tightly packed atoms.
For instance, you know a cork floats on water, but a rock doesn't.
Experiment 1.1, Density in Nature
For our liquids, we used vegetable oil, water, and corn syrup.  The kids poured these into a glass in that order and watched as the more dense liquids swirled and collected below the less dense liquids.
Then the kids dropped in a rock, a grape, an ice cube, and a cork.

If you look closely, you can see that the ice is suspended in the oil, not sitting on top of the water.
Per an email reply from Apologia, "... the ice should have been in between the oil and liquid water but if the ice cube has air trapped in it (and you might not be able to see the air) then this would drop the density of the ice cube to be equal to or less than the oil.  Since the ice cube was suspended in the oil then the density of your ice cube was nearly equal to that of the oil."
Thanks, Apologia!  I was wondering about that.  =)
From the top down, we see the least dense items to the most dense items.  Cork, vegetable oil, ice cube, water, grape, corn syrup, rock.

►Next time, we might try this Amazing Density Tower!

A day or so after this experiment, one of my kids wasn't doing her chore...  I opened the door and reminded her to tend to the next step in the laundry (from dryer to living room/from washer to dryer/put in a new load).
Five minutes later I'm not hearing a dryer running, nor do I see clean laundry anywhere.
I open the door again and smile at my child.  She smiles back.  We smile at each other for a bit, she with a slightly quizzical look.  My son finally asks what am I doing, and I said, "I'm waiting on _____ to do the laundry."
"Oh!" my forgetful child laughs, getting up, "Haha, okay."
"Did you really not know why I was looking at you?"
"Well... uh, no."
I grinned, "If I threw all you kids into a pool, you'd sink to the bottom first since you're the most dense."
She smiled, "Hehe, funny science joke."  =)

Experiment 1.2, Atomic Motion
Q:  Which is faster, hot or cold?
A:  Hot!  You can catch a cold.  =)
This is actually true.  Hot atoms move faster than cold ones.  I know I move slower when I'm cold, haha.
The kids had a large glass of refrigerator-cold water and a glass of very hot water, heated on the stove a bit.
After letting the water settle for a minute, they dropped in some food coloring to see what would happen.

More food coloring was put into the cold water so it seems to spread faster.  It is swirling but not mixing as well as it is in the hot water.

Experiment 1.3, Chemical Change
Remember the alchemists who tried to create new substances with chemical changes?
A couple of things that indicate a chemical change rather than a physical change is the change of color, and the creation of a new substance.

First 2 Tbs. of baking soda were poured into the balloon thru the still-dry funnel, and the balloon laid aside.
Then into the bottle was poured 3/4. c. vinegar and ½ c. juice from a boiled red/purple cabbage.
The vinegar and cabbage juice when mixed together produced a new color, which was a chemical change (just like leaves changing each fall).
When the balloon was attached to the bottle and the baking soda poured in, the baking soda and vinegar produced water and carbon dioxide (a new substance).  The bottle and ballon were filled with carbon dioxide instead of oxygen.  After we took the balloon off, the bottle would stay filled with CO₂ for awhile, so Bethany lit a skewer (we were out of matches) and put it into the opening of the bottle.  It was immediately extinguished.
Fire needs oxygen in order to burn.
There are some museums that have special rooms for valuable objects such as paintings, that would be ruined by water sprinklers.  These rooms are designed, in the event of a fire, to shut and seal tightly, and the oxygen is sucked out preventing fire in those rooms.  Just be sure not to be in one when that happens!



Experiment 1.4, Mapping the Paths of the Planets.
This module talks about the Copernican theory, also called the heliocentric theory that says the sun is in the center of the universe.  Now this is something rather elementary, but we weren't just learning about the heliocentric theory, but how that Copernicus wasn't believed in favor of Ptolemy's geocentric theory - that the earth is in the center of the universe.  Ptolemy was more revered at the time than Copernicus.  Remember, "...no scientist's work should be supported because the person was great.  It should only be supported because the scientific evidence supports it!" (p. 9)  The Roman Catholic church prohibited Copernicus's book from being read!  Finally in 1543, his book was published.  Still, it took awhile for people to begin to accept this theory.

Johannes Kepler began observing the heavens in the late 1500's.  His observations were so detailed that he figured out the orbits of the planets around the sun.  He found that planets do not orbit in a circle, but in a slightly oval pattern called an ellipse.
We used two pushpins as the foci (pl. of focus point).  The sun ☼ is one of the focus points.  The other is like the imaginary equator.  It's there, but is not anything physical.


Experiment 1.4, Mapping the Paths of the Planets
To draw an ellipse, we used pushpins and double layers of cardboard (taped together) from an old science display board.  I could not buy 8 little bulletin boards!   (You can't see it under the paper, but it's there.  I had to make them small in order to get 8.)

If you measure from any point on the ellipse to each of the foci (so that your two measurements make a sort of V, even if uneven, with the tops of the V being the two foci and the bottom of the V being any point on the ellipse), depending on how far apart your pushpins are and how long your string is, the sum of those will equal about 4-5 inches.  Whatever measurement it ends up being, you can measure from any point on the ellipse to each of the two foci, and it will be the same measurement every time.

Eventually, Galileo's telescope helped show a lot of evidence for the heliocentric system that Copernicus had proposed.  The Roman Catholic church did not like this and put Galileo on trial for heresy!  He was forced to stop officially promoting the heliocentric system, however he did not stop collecting information!  The heliocentric view was not accepted until well after Galileo's death.

sMiLeS,