Tiarra Santiago
    H-18

      Ice Cream Lab 

Objective: To develop observation skills, understand the scientific process through active experimentation and comparison, and understand that chemicals can change the properties of water

Materials:

- 1/2 cup milk

- 1/2 cup whipping cream (heavy cream) 

- 1/4 cup sugar 

- 1/4 teaspoon vanilla or vanilla flavoring (vanillin)

- 3/4 cup sodium chloride (NACl) as table salt or rock salt

- 2 cups ice

- 1-quart Ziploc bag 

- 1-gallon Ziploc bag

- Thermometer 

- Measuring cup and spoons 

- Cups and spoons for eating your treat !

Procedure:

1. Add 1/4 cup sugar, 1/2 cup milk, 1/2 cup whipping cream, and 1/4 teaspoon vanilla to the quart sized Ziploc bag. Seal the bag securely 

2. Put 2 cups of ice into the gallon Ziploc bag.

3. Use a thermometer to measure and record the temperature of ice in the gallon bag.

4. Add 1/2 to 3/4 cup salt (sodium chloride) to the bag of ice.

5. Place the sealed quart bag inside the gallon bag of ice and salt. Seal the bag securely. 

6. Gently rock the gallon bag from side to side. It is best to hold it by the top seal or to have gloves or a cloth between the bag and your hands because the bag will be cold enough to damage your skin.

7. Continue to rock the bag for 10-15 minutes or until the contents of the quart bag have solidified into ice cream.

8. Open the gallon bag and use the thermometer to measure and record the temperature of salt/ice mixture. 

9. Remove the quart bag, open it, serve the contents into cups with spoons.

Data:

1. What kind of ice cream are you making? 
  Strawberry   

2. Document the temperature of the ice in the gallon bag before adding salt.
      0 degrees C      

3. Document the temperature of the ice/salt mixture (not the ice cream) in the gallon bag when the ice cream mixture begins to solidify.       20 degrees C     * Do not put the thermometer in the ice cream bag 

4. What is the temperature difference before adding the salt and after mixing for 5 minutes?
    -10 degrees C    

5. What is the temperature difference before adding the salt and after mixing for 10 minutes? 
  -9 degrees C    

1.   What kind of chemical reaction is the process of ice cream making, as done in our lab? Explain why.

2.  Explain why salt water is harder to freeze than plain water.

3.  Is the process of making ice cream a physical or chemical change? Explain your answer
      
               The process of making ice cream can both be a physical and chemical change. Physical because in the process of shaking the bag of ice with the substances inside, it is creating it to freeze and solidify. Leaving the ice cream out in warmer temperatures causes it to return back to a liquid. It can also me a chemical change because the ingredients that were mixed together can no longer be separated. 

4.   Why is salt used with the ice instead of sugar ?

         
             When sugar is dissolved into water (aq), there is only a single molecule in solution. When salt dissolves into water, it breaks into two ions, a sodium ion and a chloride ion, which causes the salt to be more effective.

Sources 

http://www.sciencebuddies.org/science-fair-projects/phpBB3/viewtopic.php?f=31&t=11447

                                Ice Cream Video 

file:///Users/owner/Desktop/How%20to%20make%20Ice%20Cream%20.mov