Cassandra Johanns
SCIE 201 MWF 8 am
Deming and Franz
Atoms Unit- February 24, 2010
Science Content
- For this Unit we did multiple experiments to determine if atoms do exist. After the
experiments we took the data that we gather and made charts and graphs to
prove our theory about atoms and their existence. From there we observed the
graphs to see if they were linear. After we made connections from the graphs
we made connections from the experiments to the existence of atoms.
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The Atom Unit’s main purpose was to prove that atoms do exist. This also
explores the relationship of a substance before and after heating by the change
in mass and color. With this lab you need explore beyond physical observations
that occur before and after heating and notice the changes that chemically take
place as well. With seeing beyond the physical characteristics we are able to
see how the substance reacts chemically to the change. With seeing this change
we know the relationship of the atoms to the experiment.
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Our first experiment was with a Think Tube. We were to determine how the
strings were to be arranged inside the sealed tube without the direct knowledge
of how it was constructed. The challenge was to draw a representation of the
inside of the Think Tube. Observations of the strings outside the tube will be
used to determine the interior of the inside of the tube. From there “if and then”
statements were needed to predict the outcome of the movements of the strings.
Three different situations of the pulling of the strings occurred. The “if” statement
was always constant. The “if” statement was the Think Tube. The “and”
statement was given, because that was the thing that was changing each of the
three times. The change was the different way you can pull the string. The
“then” statement is needed to predict the outcome of the pulling of the string.
After the three different pulls, observations were put together to determine the
inside of the Think Tube. In this experiment we could not see what was being
done inside the tube but we did now that something in there was creating the
different manipulations of the pulling of the strings. Atoms and the inside of the
Think Tube are similar because we know that they exist but it not visible to the
eye. In the Think Tube you cannot see the inside but the inside is the thing that
holds everything together and that is the same thing with atoms.
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While doing this unit we had to resort back to two models. The first model was
one that dealt with magnets. This model signified the North Pole and South Pole
of a magnet and how they attract. It demonstrated that you need to use ratios
when dealing with data. When using ratios you have fixed and constant rations
when adding substances to your mixtures. This is the same concept when
dealing with atoms. Atoms are always constant and they are always the same.
The second model worked with food coloring. For this we added various
amounts of yellow and blue to make different types of green. This experiment
represented varied ratios. When using various ratios you do not know the
amounts of a substance you are adding to a mixture. Atoms cannot relate to the
food coloring model because atoms are not varied ratios they are fixed. After
each experiment that was done we had to come back to these models and state
if the experiment resembled the magnet model or the food coloring model.
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During our second experiment we worked with hydrate copper and its
relationship between the mass before and after heating. The first thing that was
done was an observation of the qualitative data of the hydrate copper; we noted
that it was a blue-green color. Then the hydrate copper was applied to heat over
the flame. As the hydrate copper heated it started turning to a dull blue-green
and eventually turned to gray. When it was heating you could see that the water
was evaporating out of it and was creating steam that escaped from the top of
the test tube. After the test tube and its contents finished heating water droplets
were added to the tube. When the water were added, the color blue-green
returned to the copper. We then moved on to the quantitative data of the
hydrate copper. We noted that the hydrated copper was .502 grams before
heating. Then after heating the copper it was .312 grams. We then also took the
data that was given to us and made a graph of the finding of the weight of the
copper before and after heating. We discovered that when heating the copper all
forms of water was taken out of the copper. From there we took the results from
that graph and made a new graph showing water loss in copper. We then found
that copper has 36.21 percent of water in it. We then realized that this
experiment was like the magnet model and not like the food coloring model.
Since the copper had a ratio and used a fixed amount of water we knew that it
was the magnet model because it also has a fixed ratio. We know that it is a
fixed ratio because there is a straight line on the graph. The straight line shows
that there is a constant ratio between the anhydrate and the hydrate. This
experiment relates to atoms because there is something changing. If nothing
changed when we heated the copper then atoms would be nonexistent. We
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know that atoms exist with this experiment because the mass of the copper
decreases as we add heat to it.
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Anhydro
y = 0.6374x us (g)
1
0
0
2
Hydrated (g)
-
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Linear
(Anhydro
us (g))
Water Loss (g)
Water Loss (g)
Anhydrous (g)
Anhydrous (g)
1
y = 0.3641x
Water
Loss (g)
4
Linear
(Water
Loss (g))
0.5
0
0
2
Hydrated (g)
Experiment three also deals with copper. In this experiment we are looking for
the mass relationship in the reaction of copper and sulfur. The weight of the
copper before the heating was .689 grams and sulfur was .262 grams. Together
they weighted .951 grams. Before they were heated they were in their natural
form, copper was its copper metal tone and the sulfur was a yellow powder.
After the heating the weight stayed close to the same amount as before at .93
grams. We also noticed that the color of the copper and sulfur had turned to
gray. This shows us that there is evidence that the original substance was
combined with the subsistence added creating a new compound. We then were
also given more data because you always want to have more data so that your
results can be more accurate, so we took the data given to us to create a graph.
We were able to use the data collected to come up with formulas to determine
the ratios between each element in the reactant used. The ratios allow us to
predict the outcome of different substances. The ratios also helped us support
the data on our graph. The graph was very accurate like the graph in the second
experiment. The graph had a linear line showing us that the data was consistent.
The first graph shows the relationship between the copper and sulfur. Then the
second graph that was created was on the relationship of the sulfur and the mass
of the product formed. We were then given another experiment that was similar
to the copper-sulfur experiment. In this experiment it showed a fixed ratio
between oxygen and magnesium. This experiment just gave us more proof for
fixed ratios. This is also like the magnet model because we are having a
controlled experiment. The linear graph also represents that because it can tell
us exact predictions. This experiment also relates to atoms because like
experiment two, things are changing. We know that atoms exist because the
mass of the copper and sulfur changed when added to heat.
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Copper and Sulfur
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Mass
of 2
Sulfur 1
(g)
0
-
y = Series1
0.2823x
Linear
(Series1
0
10
Mass of Copper (g))
Proudct Formed
15
Mass of
10
Product
Formed 5
(g)
0
y = 1.2823x
Series1
0
5
10
Linear
(Series1)
Mass of Copper (g)
The fourth and final experiment was done on the volume relationship of the
products of the decomposition of water. We tested the positive and negative
relationships of water. To start the experiment we filled two tubes up with equal
amounts of water. We then placed a positive charge on one and a negative
charge on the other. We saw that in both of the tubes bubbles started to form
and they released to the top of the tubes of water. In the negatively charged
tube’s water decreased at a very fast rate while the positively charged tube’s
water decreased at a steadier rate. After the electricity was placed into the tubes
a split test was taken. The negatively charged gas put out the fame. Then the
positively charged gas caused the flame to ignite. The spilt test shows us the
different reactions to positively and negatively charged gases. This experiment is
like the magnet model. We are starting with one compound and trying to
separate it and make it into two separate substances. We know that water is a
compound because we were able to separate the two different substances from it
when conducting this lab. This experiment was also like the magnets because
we have fixed portions. We are measuring the amounts of what is being used.
We can also take what we have and compare them with other students and have
relatively the same data. This experiment relates to atoms because of its
positive and negative charges. Atoms have both positive and negative charges
and with those charges bring different characteristics. That is the same with the
experiment we just did. The negative charge took out the flame while the
positive charge ignited the flame. Both charges bring different aspects to them.
Educational Connections
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Making Connections
In all four experiments we conducted plus the two models on food coloring and
magnets, all related back to how atoms exist. We may not always see atoms
with the naked eye, we just have to know that they are the basic building blocks
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of matter that make up everyday objects like the chair we sit in to the desk we
write on. The first experiment that we did with the Think Tube demonstrated just
that. It showed us that just because we cannot see it does not mean that it does
not exist. Without the inside of the tube the whole model would fail to exist and
that is the same as an atom. We also know if something is subject to change
that something has to exist to allow that change. The second and third
experiments show that an atom exists because there is a change is mass when a
substance is heated. Since the mass changed, that gives us evidence atoms
appear. The last bit of evidence that allows us to believe that atoms exist is the
characteristics of positively and negatively charged gases. Atoms have both
positive and negative charges and those charges allow different characteristics.
The fourth experiment dealing with positive and negative charges, gives a great
understanding of the atom. In the experiment the positive charge ignited the
flame while the negative charge diminished the flame. This is a representation of
the different characteristics that a atom has. In all the experiments they are also
related back to the magnet model, while none of them related to the food
coloring. This was because the magnet model showed us a fixed ratio and the
food coloring showed a varied ratio and the atom is a fixed ration proving all of
our finding true.
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Ideas for the Classroom
I find the concept of this Atom Unit good and interesting. I believe with a couple
adjustments to the unit it can be very beneficial and the kids will respond to it
more. I feel like you could take this unit with two different age groups. You could
do this experiment with High School and Middle School students. With High
School students, the first thing I would do would be taking a couple of days
teaching them about atoms. I would give them a general understanding of atoms
and their characteristics. By doing it this way they can go into the experiments
and be able to identify the connection of how atoms exist. Now they have the
basic knowledge of an atom and from there you can start the same experiments
with them. I believe that with the knowledge beforehand they will be able to
tackle the same experiments that were listed above earlier then without that
basic knowledge. With the Middle School students I would take a little different
approach on things. I would still start them with a clear understanding of what an
atom is and its characteristics but then I would change up the experiments so
that they can be more on their levels. I would make the experiments more hands
on because I feel like they would interpret the data more clearly that way.
Overall, the concept of the Atom Unit is good and having them make the
connection is beneficial because atoms are all around us.
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