I found everyday fun activities to do different science experiences using magnets. A great resource is Science Experience for the Early Childhood Years: An Integrated Affective Approach by Jean D. Harlan And Mary S. Rivkin. Although the tiltle says early childhood years, the experiences can be used for kindergarden as well.
In this book, chapter 11 (Magnetism) list the following concepts:
a. Magnets attract some things but not others.
b. Magnets vary in strength.
c. Magnets pull through some materials.
d. One magnet can be used to make another magnet.
e. Magnets are strongest at each end.
f. Each end of a magnet acts differently.
Im sure there will be ideas you can choose and use with your students. I hope this helps!