Evaluate the students ability on following the scientific process and being able to list the variables in the experiment. I usually use a rubric to assess laboratory work.
Student Resource
PagesGrade Level: 4-10
Objective:
Students will be able to use the scientific process in order to solve the mystery of the milk.
Indiana Standards Met with this Activity:
Standard #4 - The teacher of science understands and uses a variety of instructional strategies to encourage students' development of conceptual understanding, inquiry skills, and scientific habits of mind.
Standard #5 - The teacher of science understands and uses a variety of communication techniques to foster equity, inquiry, collaboration, and supportive interaction in the classroom.
Materials:
petri dishes (or small shallow dish)
room temperature whole milk
4 colors of food coloring (a set per group)
liquid dish soap (Palmolive works very well)
dropper
beakers
Procedure:
* Put the students into small groups (2-4)
* Make sure all groups have the correct materials, science journals and scientific process worksheets, and pencils.
* Write the title of the lab and the problem on the board. Students should copy the information onto their scientific process worksheet.Title: Mysterious Milk Lab
Problem: What will happen when food coloring and liquid dish soap are carefully dropped into the container of milk?* Have the students research information about the following terms:
variables
molecules
food colors (what is it made of?)
dish soap
whole milk* After researching the information, have them develop a hypothesis based on what they learned.
* Students should check to make sure they have all of their materials.
* The students should follow the step by step procedure of the experiment.
* Have the students write down their observations.
* Students should list the variables in the experiment.
* Students should draw a conclusion - including a list of "What ifs", thinking about what variable they would like to change. Encourage students to be creative. Give hints as needed (change in milk temperature, change in amounts of materials, substitute one of the materials, etc.).
This lab can be performed in one day (45 minute period), or students can change one variable every day over a period of time. It depends on how involved you want your students to learn about variables.
Answer:
The room temperature whole milk contains fat molecules. The only reason the food coloring is used in this experiment is for display purposes. The food coloring helps the students see the movement of the molecules. When the liquid dish soap is dropped into the center of the milk, the soap molecules go in "head" first. The head of the soap molecule goes into the milk, while the tail of the molecule stays above the surface. Fat molecules in the milk are dispersed and move away from the soap molecules. Of course, surface tension also plays a role in the movement of molecules. The result is a pretty display of color that is moved below the milk and back to the center.
Assessment:
Evaluate the students ability on following the scientific process and being able to list the variables in the experiment. I usually use a rubric to assess laboratory work.