I start the lesson with a problem of the day to help students review skills and concepts from prior lessons and develop their ability to problem solve. I call the students up to the carpet. The students find their spots while saying this chant with me.
Criss cross, applesauce, hands in your lap, eyes on the teacher, you've got to show me that.
I project the Problem of the Day on the SMART Board and say to students, "This is our Problem of the Day for today. Look at the two groups. How are they different?" I call a student to tell how the the two groups are different. I ask the other students for more differences. If it is not mentioned, I add that there are four dogs and only three bones. I ask students, "Which group has more?" The dogs. "What can we say about the group of bones?" It has less.
I tell students, "Today we will be comparing objects and sorting them into two groups. We will be doing this through a science experiment!"
I have the students move into a circle. I remind students to sit criss cross applesauce with their bottoms on the hard floor so that there is room for everyone. I put a bucket of water and two sorting circles in the middle of the carpet. I tell students, "We will be sorting objects based on if they sink or float. When things sink, they go to the bottom of the bucket. They go under the water. When things float, they stay at the top of the water." I call each student up to put an object in the bucket of water. I then have the student put the object in the yellow sorting circle if it floats and in the red sorting circle if it sinks. I have several objects pulled out ahead of time to be used in the experiment. When I run out of objects, I allow the remaining students to find something else in the room that they would like to use in the experiment. I tell students that I have to give them the okay before they can put it in the water because some things will break if we put them in water. I continue this until all of the students have had a turn.
This lesson reinforces the concept of sorting which we have been working on in math while also introducing students to the science concept of sinking and floating. While the Core State Standard K.CC.C.6 looks for students to be able to identify whether the number of objects in one group is greater than, less than, or equal to the number of objects in another group it is also important that kindergarten students are able to sort objects into groups prior to making this comparison. Recognizing that objects can be sorted into groups based on a variety of characteristics requires logical thinking, an ability that will be important when kindergarteners are required to make other decisions. Also, understanding the relationship between the different groups and being able to discuss that relationship hones analytical skills.
When all students have had a turn, I give each student a paper to take back to their seats. I tell the students that they need to circle the objects that float and put an X on the objects that sink. I tell students to put their heads down when they are finished. While students work, I project the Float or Sink worksheet on the SMART Board. I go over the paper quickly with the students by having them put up their hands up if the object I point to floats. I mark the answers on my worksheet. When we are finished, I ask students the question at the bottom of the paper. "Do more objects float or sink?" We count the number of circled objects and the number of objects that are crossed out. I tell students to circle the word "float" because more of the objects pictured float.
I have students put their papers in their mailboxes to take home. I then allow the students to work on their centers for the remaining math time.
I close this lesson by inviting students back up to the carpet. I turn on the projector and document camera and show the float or sink worksheet on the screen. I ask, "What did we learn in math today?" I review what we did during our whole group lesson. "Today we sorted objects to see what objects sink and what objects float. We found more objects that float during our experiment and on our worksheet. Tomorrow, we are going to finish up our Comparing and Sorting unit with a short test. Don't be nervous about the test. It is just like the papers that we have been doing. You are going to get to show me all that you learned about comparing and sorting!"