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Ice Cream Lab. Background Materials Procedure. Matter. What is matter? Anything that has mass and takes up space What are the three main states (or phases) of matter? Solid, Liquid, and Gas. How much energy is present in each state of matter? (relatively speaking).
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Ice Cream Lab Background Materials Procedure
Matter • What is matter? Anything that has mass and takes up space • What are the three main states (or phases) of matter? Solid, Liquid, and Gas
How much energy is present in each state of matter? (relatively speaking) • Solids - particles are vibrating in place; not much movement • Liquids - particles move around; sliding past each other • Gases - particles are moving all over the place; moving in straight lines and bouncing off things Less Energy Solid Gas More Energy
Physical States of Water So, a change of state is a physical change not a chemical change.
Phases of Matter & Relative Energy We want answers. We want the truth. Gas WAIT - If the energy is changing why isn’t the temperature? L & G 100 Temperature (Deg. C) Liquid S & L 0 Solid Energy Taken Away or Added
BECAUSE: The energy is being absorbed or released by the matter as it changes states! No, not from Pennsylvania to West Virginia, from Solids to Liquids and Liquids to Gasesand vice versa.
So, what does this have to do with ice cream? • When we make ice cream we start with a milk and sugar mix – A LIQUID • And we end up with a frozen delight – A SOLID • We use ice and salt to make that happen and the ice has to melt.
How does the process work? • Water has colligative properties. • When an impurity (such as salt) is added to water, the boiling point is elevated and the freezing point is depressed. • That is why your parents put salt on an icy sidewalk. The ice will melt because salty ice has a lower freezing point than just ice and hopefully it is not cold enough to keep salty ice frozen.
Back to ICE CREAM • We have two different phase changes occurring. • Ice melting (Solid to Liquid) • Ice cream mix freezing (Liquid to Solid) For these phase changes to occur energy is transferred – from the ice cream mix to the ice.
Ice Cream Lab - materials • Ingredients • .5 liters milk • 110 ml sugar • 2.5 ml vanilla • 1.5 liters ice • 180 ml salt • toppings Hey, wait. My measuring cups are in English Units. Uh-oh, CONVERSIONS
Ice Cream Lab – materialsin English units • Ingredients • .5 liters milk = .53 quarts ~ 2 cups • 110 ml sugar = 3.63 ounces ~ ½ cup • 2.5 ml vanilla = .5 teaspoon • 1.5 liters ice = 1.6 quarts ~ 6 cups • 180 ml salt = 5.94 ounces ~ ¾ cup • toppings
Ice Cream Lab – more materials • 1 gallon size Ziplock bag • 1 quart size Ziplock bag • measuring cups • measuring spoons • spoons • bowls
Procedure • Put milk, sugar, and vanilla into quart bag. Squeeze out as much air as possible and close bag securely. • Place quart bag in gallon bag. Add ice and salt. Seal large bag. • Knead the small bag inside the large bag to expose the mixture to the cold temperatures. You can also roll the bag back and forth on the lab table. • Knead for about 10 minutes. Check to see if the mixture is frozen. If not knead longer. • When frozen remove smaller bag. Carefully open it, being sure to wipe seal of salt water first. Place in cups, top, enjoy. • Answer and turn in analysis questions.
OKAY Go for it.