Dancing Raisins

Carbon dioxide gas dissolved in soft drinks give them their fizz. In this experiement, carbon dioxide fizz from sprite will make the raisins "dance." From this experiment, students should understand that the raisins will sink initially because they are denser than the liquid they have been dropped in. Students will also be able to explain that the soda has carbon dioxide releasing in the form of bubbles. These bubbles attach to the raisin's rough outer coating. These bubbles make the raisins bouyant, so they begin to rise. When they hit the surface, they lose the bubbles, and fall back down again. The process of the constant dancing gives the teacher (and students) many opportunities to go over what exactly is going on. In conclusion, students will need to be able to define the terms "bouyancy" and "density.

Your basic sinking and floating will be taught from pre-primary levels to the primary grades. This particular activity can be used as whole-class (in which each student drops a raisin in one "team" glass of sprite) or can be used as a lab in which individuals or partners have a more private experience with a glass of their own. This activity can be done with any class size. I have found the raisins will "dance" for over an hour (or until the pop runs flat), and there is no equipment needed other than a tall (about 8-12 inches) clear glass, raisins (anywhere between 10 and 30 is a good number of raisins)and a can of sprite. The terms sinking and floating should already be known by the students, so they can make accurate observations right away. The terms bouyancy and density should be introduced during the activity, and learned by the time the activity is done. Other follow-up activities should be done to enhance knowledge of these two terms. One way I tied this activity to another setting was to incorporate it with the food guide pyramid. What part of the chart would the raisins fall under? Healthy or unhealthy?

I will introduce this lesson by going over what it means to sink, and what it means to float. We will talk about items we can think of that float and sink, and what characteristics those items have in common/don't have in common with each other. Next, I will intorduce the terms density and bouyancy. In order to help the students better understand the meaning of these new terms, I will use the dancing raisins experiment. As the students are dropping raisins into the sprite, I will describe what is going on. Of course, the materials used are raisins, sprite, and a tall clear glass. As students drop their raisins in one at a time, they are listening and observing what is going on (this is also a time for me to answer many questions). I will allow students to take a closer look in small groups around other glasses of sprite. However, I will not allow this until my explanation is complete. As a closing strategy, I will have the groups each take turns describing to the class what is going on. For example, they will tell how/why the raisins dance using the terms sink, float, density, and bouyancy. Since this is the first day of learning about bouyancy and density, the groups will work as a team to explain the process, and may also be guided by me as their teacher. Hint: For a better description of exactly what the students should be able to explain, see the "Goals" portion of this activity sheet.

This activity can be found here: http://www.primaryscience.ie/media/pdfs/col/dancing_raisins.pdf

It is important to go very slow when discussing bouyancy and density. Although students may understand sinking and floating, density and bouyancy are completely new vocabulary words and are easily misunderstood. When students get into their groups, make sure you are checking in with all groups and clearing up any misunderstandings or confusions students may have. Also, remind students not to eat the raisins or drink the pop, as they will want to. I am not a science teacher, so I cannot say how this activity is different than experiments I have done in the past.

For the particular experiment, I would informally assess the students, since it is day one. I would do this by simply listening to the group descriptions done during closure time. However, as the terms bouyancy and density are played with through further experiments, a written definition of the words will be required (on a typical science test). I may also do a verbal multiple choice test, having students determine what it means to be "bouyant" and "denser."

3.1.1.1.1. Explanations