2 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
3 How much energy is present in each state of matter How much energy is present in each state of matter? (relatively speaking)Less EnergySolidSolids - particles are vibrating in place; not much movementLiquids - particles move around; sliding past each otherGases - particles are moving all over the place; moving in straight lines and bouncing off thingsGasMore Energy
4 Physical States of Water WHAT WE CALL ITCHEMICAL COMPOSITIONSOLIDICEH2OLIQUIDWATERGASVAPORSo, a change of state is a physical change not a chemical change.
5 Phases of Matter & Relative Energy We want answers.We want the truth.GasWAIT - If the energyis changing whyisn’t the temperature?L & G100Temperature (Deg. C)LiquidS & LSolidEnergyTaken Away or Added
6 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 Gases and vice versa.
7 So, what does this have to do with ice cream? When we make ice cream we start with a milk and sugar mix – A LIQUIDAnd we end up with a frozen delight – A SOLIDWe use ice and salt to make that happen and the ice has to melt.
8 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.
9 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.
10 Ice Cream Lab - materials Ingredients .5 liters milk110 ml sugar2.5 ml vanilla1.5 liters ice180 ml salttoppingsHey, wait. My measuring cups are in English Units. Uh-oh, CONVERSIONS
11 Ice Cream Lab – materials in English units Ingredients .5 liters milk = .53 quarts ~ 2 cups110 ml sugar = 3.63 ounces ~ ½ cup2.5 ml vanilla = .5 teaspoon1.5 liters ice = 1.6 quarts ~ 6 cups180 ml salt = 5.94 ounces ~ ¾ cuptoppings
13 ProcedurePut 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.