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2. Question Which substance will cause the ice to melt fastest?
3. Hypothesis My hypothesis is that if people poor salt on the road when there is a lot of snow on the ground then salt will probably make the ice melt the fastest.
4. Procedure Do research on the terms and concepts.
You will need a clean plate and several ice cubes for each of the variables.
Use a balance to measure the mass of the ice cube.
Note the starting time, then carefully sprinkle one teaspoon of substance.
After a good amount of time pour off the melted water into a measuring cup, and use the balance to measure the mass.
Measure the remaining mass of the ice cube.
Repeat three times for each substance to be tested.
Use the same procedure to measure the ice cubes without the substances.
For each test, calculate the percentage of the ice cube that melted. [remaining mass of ice cube]/[initial mass of ice cube] X 100. the results
For each test, calculate the percentage of the ice cube remaining. [remaining mass of ice cube]/[initial mass of ice cube] X 100.
Write down the results of the substances on a piece of paper.
Did any of the substances speed up melting of the ice?
5. Abstract The purpose of this project was to find out what substance would make ice melt fastest. I used salt, sand, sugar, and pepper. I compared the time and the amount of ice that melted. We came to a conclusion that salt melts the ice fastest.
8. Data and Results Salt made the ice melt fastest by lowering the freezing point.
9. Conclusion My Hypothesis was correct! Salt melted the ice faster than all of the other variables.
10. Application I would apply this to real life for people who live in cold climates. They could poor salt on the snow to melt it instead of them shoveling it.
11. Data Log 9/2 ? 9/20 = Deciding on my project.
9/21 = Found my project that I was going to do.
9/22 = Collected all my variables for the project.
9/23 = Did half of my project and collected all data.
9/24 = Finished my project and collected other half of my data.
9/25 = Bundled all of my data together and came to my conclusion.
9/26 = Put down all info on posterboard and finished project.
12. 5 Paragraph Essay
To make ice cream with an old-fashioned hand-crank machine, you need ice and rock salt to make the cream mixture cold enough to freeze. If you live in a cold climate, you've seen the trucks that salt and sand the streets after a snowfall to prevent ice from building up on the roads. In both of these instances, salt is acting to lower the freezing point of water.
For the ice cream maker, because the rock salt lowers the freezing point of the ice, the temperature of the ice/rock salt mixture can go below the normal freezing point of water. This makes it possible to freeze the ice cream mixture in the inner container of the ice cream machine. For the salt spread on streets in wintertime, the lowered freezing point means that snow and ice can melt even when the weather is below the normal freezing point of water. Both the ice cream maker and road salt are examples of freezing point depression.
Salt water is an example of a chemical solution. In a solution, there is a solvent a solute. A molecule of the solute will dissolve when the force of attraction between solute molecule and the solvent molecules is greater than the force of attraction between the molecules of the solute. Water is a good solvent because it is partially polarized. The hydrogen ends of the water molecule have a partial positive charge, and the oxygen end of the molecule has a partial negative charge. This is because the oxygen atom holds on more tightly to the electrons it shares with the hydrogen atoms. The partial charges make it possible for water molecules to arrange themselves around charged atoms in solution, like the sodium and chloride ions that dissociate when table salt dissolves in water.
The balance between freezing and melting processes can easily be upset. If the ice/water mixture is cooled, the molecules move slower. The slower-moving molecules are more easily captured by the ice, and freezing occurs at a greater rate than melting. Conversely, heating the mixture makes the molecules move faster on average, and melting is favored. Adding salt to the system will also disrupt the equilibrium. Consider replacing some of the water molecules with molecules of some other substance. The foreign molecules dissolve in the water, but do not pack easily into the array of molecules in the solid. The total number of waters captured by the ice per second goes down, so the rate of freezing goes down. The rate of melting is unchanged by the presence of the foreign material, so melting occurs faster than freezing.
In conclusion you now know why salt causes the ice to melt faster than usual. This happens because it makes it harder for water to form a crystal structure. This is because there is stuff in the way. What this means is that it has to get a little bit colder for impure water to freeze then pure water. Which causes the melt speed to increase tremendously! Now you know all the detail on why salt makes ice melt fastest.
13. Bibliography www.Sciencebuddies.com
Frank, D.V Little