Mystery Mixture Demo

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Mystery Mixture Demo

• Mr. V. Perez
• Grade 6 Science

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• 1. We discussed different types of mixtures in
  class (solutions, suspensions, emulsions, and
  colloids). What kind of mixture was made when we
  added milk with the sugar and vanilla? How could
  you tell? (Hint This kind of mixture has two
  types.)

• The mixture is a permanent emulsion or colloid.
  The molecules of fat in the milk are suspended in
  a sugar water solution with air bubbles.

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• 2. Why was salt added to the ice in the coffee
  tin?

• The salt that mixes with ice creates a brine
  solution (saltwater). The brine solution lowers
  the freezing point below 0 ºC.

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• 3. What do we call the process that was
  described in question 2 above?

• Freezing Point Depression

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4. How was the solution in the bag able to
freeze?

• As the temperature in the bag drops below
  freezing (0 ºC), the brine solution started to
  crystallize the milk into a solid.

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5. The real mixture uses an emulsifying agent
called xanthan gum. As discussed in class, why
is an emulsifying agent needed in this mixture?

• The emulsifying agent keeps the milk fat and air
  bubbles together in a smooth texture.

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6. The sugar is needed in this mixture to
prevent it from crystallizing too quickly. Why
would it be a problem if this solution was able
to crystallize?

• The sugar, which is the added solute, prevents
  the complete crystallizing of the milk solution
  because it lowers the freezing point. The ice
  cream remains creamy, and not a complete solid