The effect of big and small NaCl(s) particles on ice
L. Dulos & M. van de Mosselaar
Kandinsky College Nijmegen, The Netherlands
Received April 2011
Summary
During the winter salt is often used to melt the ice on roads. This will let the ice freeze at a
lower temperature and so will delay the formation of ice. But which salt is used? Since the
form and size of the salt will have a different effect on the melting of ice, for example small
NaCl(s) particles compared big NaCl(s), a particular salt will be used. This raises the
question: what will the effect of big and small NaCl(s) particles be on ice? Comparing the
results of the effect of small NaCl(s) particles and big NaCl(s) particles on the melting of ice
and the melting of plain ice, we found that ice treated with small salt particles has a faster
melting process. But it also raised further questions such as: Will the different sizes of
NaCl(s) particles have different effects on plants?
Introduction
What is the effect of big and small NaCl(s)
particles on the melting of H2O(s)?
Our hypothesis is that the melting progress
of the ice with and without the NaCl(s)
will start slowly, because in the beginning
there will be no H2O(l) available. A
surface of water on the ice will soon be
formed and speed up the melting process.
In which the ice treated with the small
NaCl(s) particle will melt faster compared
the other NaCl(s) and the ice without
NaCl(s). This is because the small NaCl(s)
particles have a larger degree distribution
than the big NaCl(s) particles. This means
that they have a larger surface compared to
the big particles and in proportion to their
weight, and so these small particles will
have more direct contact with H2O(s).
Figure 1: Glass beakers containing
untreated ice and ice treated with small and
big NaCl(s) particles.
Figure 2: Measuring cylinders with funnels
Experimental procedure and approach
We took identical measuring cylinders and
six identical glass beakers. The ice was put
in the glass beakers, each 50 grams of
H2O(s). Two of them were treated with 5.0
grams of big NaCl(s) particles, two were
treated with 5.0 grams of small NaCl(s)
particles and the remaining two were not
treated.
Data gathering and analysis
Then every 5 minutes the amount of
H2O(l) that appeared in the glass beaker
was put in the measuring cylinders and
was noted till all the ice of one set-up was
melted. The average values for each
moment were put in a table from where we
could put these values in a graph. Then the
graph was analyzed for similarities and
differences between the three set-ups.
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Results
We observed that when we added the
NaCl(s) both of the glass beakers
containing ice treated with big and small of
salt formed a layer of water. The glass
beaker containing the untreated ice did not
form a layer of water during the first five
minutes. Eventually it took 125 minutes
for the ice in one of the glass beakers to
completely melt. Table 1 shows the
averaged amount of melted water (in mL)
of ice that was treated with small or big
particles of NaCl(s) and without NaCl(s).
Time
Without
(in
NaCl(s)
minutes) (mL)
With
small
NaCl(s)
particles
(mL)
0
0
0
0
0
6.25
6
5
2.75
10.25
10
10
5.5
13.75
13.5
15
8.25
15.5
17
20
11.25
18.25
21.25
25
13.5
20.5
23.75
30
15
22
25
35
16
23.5
26.75
40
18
25
28.5
45
19
26.5
30
50
20
28
31.5
55
21
29.5
33
60
22.5
31
34
65
24
32.5
35
70
26
33
36
75
27
34.5
37.5
80
28
35.5
38.75
85
39.5
37
39.5
90
31
38.25
41
95
32
39.5
42.5
100
33
40.5
44.25
105
35
41.5
45
110
37
42
46.5
115
39
43
48
120
42
45.75
51.25
125
Table 1: Amount of water (mL) released
with or without treatment of NaCl(s)
ice was treated with big and small particles
of NaCl(s) and without any treatment. The
upper line (green) shows the averaged
amount of water treated with small
particles of NaCl(s). The middle line (red)
shows the averaged amount of water
treated with big particles of NaCl(s) and
the lower line (blue) shows the averaged
amount of melted water from untreated ice.
With big
NaCl(s)
particles
(mL)
Figure 3 shows the averaged measured
amount of melted H2O(l) in mL when the
Figure 3: Averaged measured amount of
released water (mL) with or without
treatment of NaCl(s)
Conclusion and discussion
If we look critical at our experiment there
are things that went well and a lot of thing
we could have improved. During our
inquiry we tried to keep our same variables
constant: the amount of ice, room
temperature, amount of salt and the time
taken. We measured the same dependent
variable (volume of melted water) and in
one of the set-ups we added small particles
of NaCl(s), in one of the set-ups we added
big particles of NaCl(s) and in one of the
set-ups we had untreated ice. In this way a
comparison between the three set-ups was
possible. To be sure that the results were
reliable we set up our experiment twice.
The average taken from the results were
put in the table and in the graph.
After about 20 minutes the melting process
of all three set-ups became equal in speed
as is indicated by the slope in figure 3.
This remained throughout the rest of the
experiment. After some time the NaCl(s),
both big and small particles, may not have
had any effect on the melting process of
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the ice anymore. This is indicated by figure
3, as both of the slopes of the ice treated
with big and small particles of NaCl(s)
compared to slope of the untreated ice are
relatively the same. An explanation could
be that all the NaCl(s) is solved and more
salt will be needed to see a further effect
on the melting process of ice. Though it
can be seen that it takes a few minutes
longer for the ice treated with small
NaCl(s) particles to become equal in speed
with the other two slopes, it has a steeper
slope. An explanation could be the
different abilities of the dissolving of
NaCl(s). This leads to an answer on our
main question. As expected in our
hypothesis ice treated with small particles
of NaCl(s) will melt a little faster than ice
treated with big particles of NaCl(s) and
ice that was not treated.
This raises further questions for inquiry:
what will the effect of more salt be? Will
the different sizes of NaCl(s) particles have
different effects on plants? Are there other
salts that will different effects on the
melting of ice comparing small and big
particles? Are there salts that will let ice
melt even more quickly? Is it possible to
use ‘green’alternatives?
Evaluation
Even though we tried to get the best results
from our experiment we could have
improved it in some ways. We could have
used the same amount of small and big
particles of NaCl(s) instead of the same
amount of grams. Would this have given
us different results? And if so, would these
results be more accurate? Would there
have been different results if we had used
crushed ice instead of ice cubes? In our
experiment we stopped measuring after
one of the ice cubes in the glass beakers
was completely melted. We could have
continued our experiment and measured
until all of the ice cubes were fully melted.
During the experiment we decanted the
amount of water of the melted ice in the
glass beakers into the measuring cylinders.
We spilled water during this procedure, if
we had done this in a different way and
made sure that no water was lost we would
have had more accurate results.
Bibliography
1. ICY – road salt booklet
2. http://www.worsleyschool.net/sci
ence/files/saltandfreezing/ofwater
.html
3. http://www.aljevragen.nl/sk/reacti
esnelheid/SNL141.html
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