Science+Experiments

April 8th, 2008 Wissahickon School District Grade 3 ** Color Collisions: From Wizbangers and Wonderments ** **Objectives**: -Students will collaborate to come up with a meaningful definition of the word scientist. -Students will predict what will take place in this experiment. -Students will make observations of the experiment. -Students will expand their thinking by coming up with questions about what took place.


 * Materials**:
 * Bowl
 * Milk
 * Food coloring
 * Dish soap
 * Student prediction worksheets
 * chart paper

Introduction: Students will look at their drawings of a scientist from the previous lesson. We will review ways they are similar and different and begin talking about what it means to be a scientist. 1. On chart paper we will come up with a definition for the word “scientist” by brainstorming phrases. 2. We will discuss why scientists are important and who some famous scientists are. 3. The materials for the color collision experiment will be set up for the students to see. 4. The teacher will demonstrate the science wonder and students will make careful observations as to what is taking place.
 * Procedures**:
 * Pour milk into pie pan and scatter food coloring drops (2-3 drops) around the center.
 * Drop a few drops of dish soap in the middle and watch as the colors are quickly pused to the outside of the pan.

5. Students will then be able to work with a partner to try the experiment on their own.
 * Allow students time to fill out their observations and make predictions why it took place
 * Closure: **
 * 6.** Guide the students into explaining how the experiment too place. (see below)

7. Students will then think of questions they still have or expand their thinking by coming up with other variables that would affect the experiment. 8. Class will discuss new possibilities if the experiment is changed and talk about where to find more information about questions still unanswered.

How does it work? Milk is mostly water but it also contains vitamins, minerals, proteins, and tiny droplets of fat suspended in solution. Fats and proteins are sensitive to changes in the surrounding solution (the milk). When you add soap, the weak chemical bonds that hold the proteins in solution are altered. It's a free for all! The molecules of protein and fat bend, roll, twist, and contort in all directions. The food color molecules are bumped and shoved everywhere, providing an easy way to observe all the invisible activity. At the same time, soap molecules combine to form a micelle, or cluster of soap molecules. These micelles distribute the fat in the milk. This rapidly mixing fat and soap causes swirling and churning where a micelle meets a fat droplet. When there are micelles and fat droplets everywhere the motion stops, but not until after you've enjoyed the show! There's another reason the colors explode the way they do. Since milk is mostly water, it has surface tension like water. The drops of food coloring floating on the surface tend to stay put. Liquid soap wrecks the surface tension by breaking the cohesive bonds between water molecules and allowing the colors to zing throughout the milk. What a party! Repeat the experiment using water in place of milk. Will you get the same eruption of color? Why or why not? What kind of milk produces the best swirling of color: skim, 1%, 2%, or whole milk? Why? Background info: draw a pic of molecules in a liquid. Explain that food we eat is made up of different things. Milk is made up of, water, vitamins, minerals, protein, and tiny drops of fat. Fats are sensitive to the changes that take place in the milk. When the soap is added it changes the way fats and proteins are held together, which causes motion. We wouldn?t be able to see this without the food coloring. The soap molecules distribute the fat within the milk. When the soap and fat droplets are everywhere the motion stops. Demonstrate on the drawing of the soap molecule that the fats move all over the place. http://www.stevespanglerscience.com/experiment/00000066
 * Teacher Reference Notes: **