Physics IA: Concentration of Salt
Physics IA: Concentration of Salt Introduction Physics as a subject has always fascinated me. Seemingly complicated theorems and equations, that have taken the very best of scientists ages to decipher, decipher, manifest themselves in everyday objects so effortlessly. effortlessly. From the falling of a small pin to the collision of entire galaxies, the presence of the physical sciences is omnipresent. Physics as a subject is so un-escapable in life that every change that has taken place in this universe since the start of time can be directly attributable to one or more of its concepts. The idea for this experiment was born when I was trying to make lemonade after playing a football match. After After playing sports, consumption of a cold drink is needed to decrease body temperature. temperature. However, However, when kept in a room, the drink eventually cools down due to absorption of heat energy in the environment. To To make lemonade, I began to mix the salt with water and wondered if the amount of salt in the water would make it warmer than a normal of glass of water if left at room temperature. Thus, it was decided to determine the optimum amount of salt, if any, needed to ensure that the drink would stay at the minimum temperature for a given time period. I linked this idea of mine to the concept of specific heat capacity which we had learnt in our Physics HL class under the topic Heat. Since specific heat capacity conveyed how much heat energy a substance could absorb for a unit mass, I realized that a substance with higher specific heat capacity would also cool down slower. Thus, Thus, I decided to explore how the specific heat capacity of my lemonade changed with different percentages of salt salt in it, which eventually became became the basis for my my research question.
P a g e 1o f 9
Titles you can't find anywhere else
Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.
Titles you can't find anywhere else
Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.
Titles you can't find anywhere else
Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.
Physics IA: Concentration of Salt
Background Theory Heat is energy that is transferred from one body to another as a result of a difference in temperature. The specific heat capacity capacity of a body is said to be the energy required to increase the temperature of a unit mass of the body by one kelvin. The literature value of the specific heat capacity of water is known to be 4200 JKg JK g−1K −1 . The literature value of specific heat capacity of salt is 864 JKg JK g−1K −1 . In the experiment, the concentration of salt in water is increased and the specific heat capacity of water is calculated for each of the different concentrations. The The Principle of Method of Mixtures. Specific heat capacity can be calculated through the formula = m c ∆ t
where Q represents the heat energy supplied to the body m represents the mass of the body c represents the specific heat capacity of the body "T
represents the change in temperature
The heat energy supplied can be calculated using the formula =
t
Where Q represents the heat energy supplied to the body
Titles you can't find anywhere else
Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.
Titles you can't find anywhere else
Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.
Physics IA: Concentration of Salt
t represents the time for which the heat energy was supplied in seconds
Research Question How does the concentration of salt in water affect the specific heat capacity of the water?
Hypothesis The specific heat capacity of water decreases proportionally with an increase in concentration of salt.
Variables Independent – concentration of salt in water Dependent – specific heat capacity of water, final temperature Controlled – initial temperature, mass of mixture, heat energy supplied
Apparatus - Calorimeter - Water - Gra Gradua duated ted Cyli ylinder nder - Salt - Voltmeter - Ammeter - Connecting wi wires - Cotton rope
Titles you can't find anywhere else
Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.
Titles you can't find anywhere else
Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.
Physics IA: Concentration of Salt
- Digi Digita tall Wei Weigh ghin ing g Sca Scale le - Batte atterry Elimi limina nattor
Safety Risks -
Wear Rubb Rubber er Glove Glovess when when using using the the connec connectin ting g wires wires to ensu ensure re no elec electri tricc shock shock occurs.
-
Procedure 1. Measure Measure a volume volume of 100 ml of water water using the graduat graduated ed cylinder cylinder 2. Pour the water water measured measured into into the copper copper vessel of the the calorimet calorimeter er 3. Record the initial temperature of the water using the digital digital thermometer thermometer 4. Connect the voltmeter and ammeter to the battery eliminator and and switch on the power generator. generator. 5. Switch Switch on the power source source for a duration duration of 10 minutes minutes while while ensuring ensuring that the the voltage is 2 Volts and the current is 2 Amperes. 6. At the end end of 10 minutes, minutes, record the final temperature of the water water using the digital thermometer.
Data Analysis The heat energy supplied was calculated using the formula =
t
Titles you can't find anywhere else
Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.
Titles you can't find anywhere else
Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.
Physics IA: Concentration of Salt
= 2400 J
The uncertainty in the value of Q was calculated in the following manner: (CHANGE THIS "Q
= ± (0.20+0.20+0.01)
"Q
= ± 0.41 = 2400 ± 0.41
Therefore,
The specific heat capacity of water was calculated using the formula = m c ∆ t
c=
Q m* Δt
Therefore, after substituting the values we arrive at c=
2400 0.1* Δt
The uncertainty in the value of c was calculated in the following manner: Δc
c
c c
=
Δ
Q
+
Δ m
m
+
Δt
t
= 0.00017 + 0.0001 + 0.00001666666
c = c* 0.00029 For each case, the difference in temperature ( Δt ) was substituted to calculate the specific heat capacity.
Raw Data Dat a Table Table
Titles you can't find anywhere else
Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.
Titles you can't find anywhere else
Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.
Physics IA: Concentration of Salt
Sr No.
Concentra tion of salt (By % of mixture)
Heat Energy Supplied (in J)
Time taken (in seconds)
Initial Temperatu re (in K)
Final Temperat ure (In K)
Difference in temperatur e ( Δt )
Specific Heat Capacity of Water (in JK g−1K −1)
1
0%
2400J
600s
298.1
303.8
5.7
4210.52
2
10%
2400J
600s
298.1
303.9
5.8
4137.93
3
20%
2400J
600s
298.1
304.1
6
4000.00
4
30%
2400J
600s
298.1
304.3
6.2
3870.96
5
40%
2400J
600s
298.1
304.6
6.5
3692.30
Processed Data Table Sr Concentr Heat Energy No. ation of salt Supplied (By % of (in J) mixture)
Time taken (in seconds)
1
600.00 ± 298.10 ± 0.01 s 0.10 K
2
0%
10%
2400 ± 0.41J
2400 ± 0.41J
600 ± 0.01 s
Initial Temperat ure (in K)
Final Tempera ture (In K)
± 0.1 K
± 0.1 K ± 0.2 K
298.1 ± 0.1 K
Difference Specific Heat in Capacity of temperatur Water(in e ( Δt ) JKg JK g− K −1)
303.80 ± 0.10 K
5.7 ± !"#
303.9 ± 0.1 K
5.8 ± !"#
%
4210.52 ± 1.22
JKg JK g−1K −1 %
4137.93 ± 1.20
JKg JK g−1K −1 3
20%
2400 ± 0.41J
600 ± 0.01 s
298.1 ± 0.1 K
304.1 ± 0.1 K
6 ± !"# %
4000.00 ± 1.16
JKg JK g−1K −1 4
30%
2400 ± 0.41J
600 ± 0.01 s
298.1 ± 0.1 K
304.3 ± 0.1 K
6.2 ± !"# %
3870.96 ± 1.12
JKg JK g−1K −1
Titles you can't find anywhere else
Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.
Titles you can't find anywhere else
Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.
Titles you can't find anywhere else
Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.
Physics IA: Concentration of Salt
Data Visualization (enter graph)
Conclusion The results of the experiment indicate that as the concentration of salt in water w ater increases, the specific heat capacity of the water decreases. Water Water without any salt is found to have higher specific heat capacity than water with salt. Therefore, water without any salt cools down slower and is optimum to ensure that the drink would stay at the minimum temperature in a given time period.
Limitations •
The copper vessel of the calorimeter could have been slightly dirty, dirty, and contained dust and other particles particles which would have affected affected the temperature change change ( Δt ) calculated, and hence the value of specific heat capacity of water that was calculated.
•
Parallax error could have occurred while measuring the volume of water using the graduated cylinder.
Titles you can't find anywhere else
Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.
Titles you can't find anywhere else
Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.
Physics IA: Concentration of Salt
•
The copper vessel of the calorimeter could be cleaned using alcohol swabs to ensure that there are no other particles remaining in it.
•
The measurement marking of the graduated cylinder should be observed perpendicularly when measuring the level of water. water. The volume should be measured by observing the lower meniscus of the graduated gr aduated cylinder.
•
An arduino module could be used along with motorised switch to ensure that the battery eliminator switches off automatically at the given time period.
•
The temperature of the water could be increased first to increase solubility of salt in water, before letting the water settle to the initial temperature.
Titles you can't find anywhere else
Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.
Titles you can't find anywhere else
Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.
Physics IA: Concentration of Salt
References https://pubs.acs.org/doi/abs/10.1021/jp0003914 http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/spht.html https://www-thphys.physics.ox.ac.uk/people/SteveSimon/condmat2012/LectureNotes2012.pdf https://www.engineeringtoolbox.com/sodium-chloride-water https://www.engineeringtoolbox.com/sodium-chloride-water-d_1187.html -d_1187.html https://www.sciencedirect.com/science/article/pii/S1876610217310342 https://www.ck12.org/book/CK-12-Chemistry-Second-Edition/r18/secti https://www.ck12.org/book/CK-12-Chemistry-Second-Edition/r18/section/17.4/ on/17.4/ http://www.iun.edu/~cpanhd/C101webnotes/matter http://www.iun.edu/~cpanhd/C101webnotes/matter-and-energy/specificheat.html -and-energy/specificheat.html