Introduction: Ice Cream Lab
What a fun way to learn! Make up some ice cream to discuss solutions, mixtures, saturation points, melting point, freezing point and physical changes.
The ice cream lab can be used at several grade levels. I use it in the fourth grade to discuss physical changes. I also used this activity in 5th, 6th, and 8th grade over my 25 years teaching. For older grade levels we discuss solutions, mixtures, saturations, ... along with the physical changes that are taking place in this tasty activity.
Step 1: Materials
Dropper or Pipette
Pint Size Freezer Bags
Quart Size Freezer Bags
Light Cream (Half and Half)
Print directions and Signs.
Step 2: Post Directions
I have been doing the ice cream lab for over 20 years and found that posting the directions is best. I no longer have students asking me 20 times what is next (even when they had a paper with directions in their hand). I now just point to the wall. Use the directions provided with this instructable or make your own.
Laminate - It is a good idea to laminate directions so they can be reused year after year and the lamination prevents the signs from getting wet.
Post to wall
Step 3: Assebly Line
I have an assembly line procedure where kids work with partners.
I have an assignment for students to work on during class. As students work at their desks I pick two students that are working well. This keeps down on the chaos as more and more kids come up to make their ice-cream. Once students are done making and eating, they can go back to their seat work.
Step 4: Add Ingredients
The first sign has the recipe of 6 Tbsp of Heavy Cream, 6 Tbsp Half and Half, 2 Tbsp of sugar, 2 drops of vanilla.
Have all ingredients and supplies out and ready. Put the ingredients and supplies in the order the students will need them.
Pick two students to come back to the ingredients.
Right at the beginning of the assembly line students are provided with one pint size freezer bag. The kids pick it up and move to the next "station".
In the following stations students "add all ingredients to the small bag" (sign two). Refer students to the first sign for the ingredients.
Seal bag completely (sign three). I have found that getting out as much air as possible helps with the mixture freezing more effectively and cuts back on bags popping open.
Step 5: Ice Time
Put the smaller bag (pint size freezer back) into a quart size freezer bag (sign four).
Fill large bag with ice (sign five).
Step 6: Add Salt
Add 2 Tbsp of ice cream salt (sign six). Seal bag.
Using the permanent marker put name on bag and set to the side.
Go back through the assembly line with partner to make their bag up.
Step 7: Shake
Once both partners have gone through the assembly line, shake the bag continuously for 10 min (seventh sign).
Have the kids watch the clock and stop after 10 minutes. No need for them to go longer. I have found that several kids have had great frozen ice cream but continued to shake past the 10 minutes and end up with a milk shake instead.
Step 8: Enjoy!
The ice cream was well set up and clearly went through a physical change. Freezing and melting are wonderful examples of a physical change and phase change.
Step 9: Ohio's Learning Standards
The standard that I want to focus on is - 4.PS.1: When objects break into smaller pieces, dissolve, or change state, the total amount of matter is conserved.
PHYSICAL SCIENCE (PS) Topic: Electricity, Heat and Matter
This topic focuses on the conservation of matter and the processes of energy transfer and transformation, especially as they apply to heat and electrical energy.
CONTENT STATEMENT4.PS.1 When objects break into smaller pieces, dissolve, or change state, the total amount of matter is conserved. When an object is broken into smaller pieces, when a solid is dissolved in a liquid or when matter changes state (solid, liquid, gas), the total amount of matter remains constant. Note:Differentiation between mass and weight is not necessary at this grade level.
Prior Concepts Related to Changes of Matter
PreK-2: Simple measuring instruments are used to observe and compare properties of objects. Changes in objects are investigated.
Grade 3: Objects are composed of matter, which has mass and takes up space. Matter includes solids, liquids and gases (air). Phase changes are explored. Heating and cooling is one way to change the state of matter.
Grade 4 Concepts: Some properties of objects may stay the same even when other properties change. For example, water can change from a liquid to a solid, but the mass of the water remains the same. Parts of an object or material may be assembled in different configurations but the mass remains the same. The sum of the mass of all parts in an object equals the mass of the object. When a solid is dissolved in a liquid, the mass of the mixture is equal to the sum of the masses of the liquid and solid. At this grade level, the discussion of conservation of matter should be limited to a macroscopic, observable level. Conservation of matter should be developed from experimental evidence collected in the classroom. After the concept has been well established with experimental data and evidence using closed systems (i.e., systems where matter cannot enter or leave the system), investigations can include interactions that are more complex where the mass may not appear to stay constant (e.g., fizzing tablets in water). Mass is an additive property of objects and volume is usually an additive property for the same material at the same conditions. However, volume is not always an additive property, especially if different substances are involved. For example, mixing alcohol with water results in a volume that is significantly less than the sum of the volumes.
Future Application of Concepts
Grades 6-8: Conservation of matter in phase changes and chemical reactions is explained by the number and type of atoms remaining constant. The idea of conservation of energy is introduced.
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