Freezing point of water
Thought process:
Why did I choose to do this project?
When I was replacing water in the ice-cube tray, I decided to have some fun and put orange juice in one tray and left it to freeze for about the same time as the water. However, when I checked the ice cube trays a few hours later, I found out that the water had frozen, while the orange juice had not. This made me think about how different liquids freeze at different rates, and ultimately, how different substances in water affect its' freezing point. This led me to find out more about the freezing point depression and thus, I got the inspiration for this experiment.After I had a rough idea of what I was going to do for my project, I searched for similar projects and and making sure that my project was feasible, I started conducting the experiment.
Why did I choose to do this project?
When I was replacing water in the ice-cube tray, I decided to have some fun and put orange juice in one tray and left it to freeze for about the same time as the water. However, when I checked the ice cube trays a few hours later, I found out that the water had frozen, while the orange juice had not. This made me think about how different liquids freeze at different rates, and ultimately, how different substances in water affect its' freezing point. This led me to find out more about the freezing point depression and thus, I got the inspiration for this experiment.After I had a rough idea of what I was going to do for my project, I searched for similar projects and and making sure that my project was feasible, I started conducting the experiment.
Materials and Apparatus I used in the experiment:
20 ml test tubes filled with 10 ml distilled water (three used for each try) :
Mercury thermometer that measures up to -10°C:
Weighing (gram) scale:
100 ml measuring cylinder:
600 ml beaker:
Stopwatch:
Ethylene glycol:
Salt:
Sugar:
Pictures taken during the experiment:
Beaker filled with ice and ethylene glycol:
Weighing two grams of salt:
Test tubes with salt and sugar added to water (not dissolved) :
Three prepared and labelled test tubes:
Test tube V1 when first ice crystals have formed:
Test tube V2 when first ice crystals have formed:
Test tube C when first ice crystals have formed:
Results:
First try
Based on the results, we know that different solutes dissolved in the solvent (water), does affect the freezing points and time taken for the solution to freeze.
Substance
|
Time (min)
|
Temperature (ºC)
|
V1
|
12.46
|
-6.5
|
V2
|
4.55
|
1
|
C
|
4.28
|
0
|
Second try
Substance
|
Time (min)
|
Temperature (ºC)
|
V1
|
12.37
|
-4.5
|
V2
|
4.13
|
2
|
C
|
3.53
|
0
|
Third try
Substance
|
Time (min)
|
Temperature (ºC)
|
V1
|
12.14
|
-5
|
V2
|
4.18
|
1.5
|
C
|
4.37
|
0
|
Average
Substance
|
Time (min)
|
Temperature (ºC)
|
V1
|
12.32
|
-5.3
|
V2
|
4.28
|
1.5
|
C
|
4.19
|
0
|
Based on the results, we know that different solutes dissolved in the solvent (water), does affect the freezing points and time taken for the solution to freeze.
