Miss Robohn's Classroom



Dry Ice Cream?(Kelsey Robohn)Relevant SOLs2.3 The student will investigate and understand basic properties of solids, liquids, and gases. Key concepts include:a) identification of distinguishing characteristics of solids, liquids, and gases; b) measurement of the mass and volume of solids and liquids; and c) changes in phases of matter with the addition or removal of energy.5.4 The student will investigate and understand that matter is anything that has mass and takes up space; and occurs as a solid, liquid, or gas. Key concepts include:a) distinguishing properties of each phase of matter; b) the effect of temperature on the phases of matter;Materials:2 metal mixing bowls2 large spoons2 metal forks2 pairs of glovesPlastic container(s) for leftoversHeavy creamVanillaAny other toppings (chocolate chips, M&M’s, coconut, chocolate syrup)EngageWhat kinds of ice cream do you like?What is dry ice? -- Carbon dioxide (CO2), which you breathe out.Is dry ice dangerous? How? -- It can burn your skin if you touch it for a few seconds. If you swallow it, it can burn your esophagus and then release lots of c02 in your stomach acid, resulting in lots of burping! So we will use gloves, and not eat any chunks left over.What is sublimation? -- Sublimation is the transition of a substance directly from solid to gas (WITHOUT passing through the liquid stage). The reverse (gas to solid) is “desublimation” or ”deposition.” You will see this in the fog that is released by the dry ice.Explore (How to make about 4 servings)Mix 10 oz. whipping cream with 6 oz. sweetened condensed milk.Add a couple spoonfuls of vanilla.Smash dry ice into a powder. Don’t touch it with your hand, as it is extremely cold and can damage skin.Have one person stir while the other pours the dry ice. Add enough dry ice to make it the consistency you want. Keep mixing so it doesn’t freeze solid!Remove chunks with your fork because you can’t eat those.Let stand for a few minutes until the dry ice dissipates (no more fog) before eating.ExplainWhat did we see happen here? The dry ice was so cold that it brought the cream to that ice creamy texture we all enjoy. Meanwhile, the dry ice sublimates.ExpandIs sublimation a physical or chemical change? -- Physical.How do they make Dippin’ Dots? They combine normal ice cream ingredients, then cryogenically flash freeze it into tiny beads. Cryogenics uses liquefied gases such as liquid nitrogen or liquid helium, NOT dry ice.Try some other dry ice experiments on Steve Spangler’s website: students draw a picture of what happened, labeling the states of matter. Then write a paragraph on what they learned, including what sublimation is.Sources: ................
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