In second grade, we take all of the concepts learned in first grade and begin to refine them. The students learn to read a full octave; they learn about keys and more complicated rhythms. We also begin to discuss all of the families of instruments to start thinking about what instrument they will pick.
Also in second grade, the students will learn two musical suites quite thoroughly. The first is "The Carnival of the Animals" by Camille Saint-Saens, It is an excellent collection of music that the children always enjoy. Below is a link to a great recording of it.The second is the "Peer Gynt" suite by Edvard Grieg. You'll probable recognize a few from this collection. It contains the famous "In the Hall of the Mountain King" as well as a few others.
I'm sure your child would love to be able to listen to them at home. I recommend that you pick up a copy and let your child tell you all about them.