The specific materials you choose for your model sun project depend on what the learning goals are, availability, size needs and the space you are working in. If you will be working directly in the fifth grade classroom, you may want to consider materials that are less messy or do not require flowing water. Although paper mache or plaster can make a stellar project, you will need water to create the necessary mixtures. Additionally, both techniques will make quite a mess and may not be practical outside of the art room. Materials with less of a mess include modeling clay or dough compounds. These malleable options are clean to use, but are still suitable for a three-dimensional project.
Before starting your model sun project, prepare your fifth graders with an introductory discussion. Fifth graders can handle in-depth facts such as the size of the sun (it has 333,000 greater times the mass of our planet), what it is made from (gases) and the surface temperature (5,500 degrees Celsius). Look at photos and scientific illustrations of the sun online at educational sites such as National Geographic or NASA. Tie your discussion into the model building process, and ask the students to talk about what shape, color and size they think their projects should be.
Create a solid model of the sun with a basic spherical shape. If you plan on using a paper mache or plaster technique, you will first need to start with a supportive armature. The easiest armature for a sun model is a blown-up balloon. Have the students cover the balloon completely with either paper strips covered in paper mache paste or plaster pieces and water. After the medium dries, use craft paints to color the sun yellow, orange and red. Encourage the fifth graders to mix and blend the paints into realistic shades. Another option is to mold a sphere out of yellow or yellow-orange clay. Have the children pierce the model with a dowel or craft stick and mount onto a wooden base with glue and cover with a layer of clay to hold.
Explore the layers of the sun with a cross section-type model. The sun is made up of six basic layers: the core, radiative zone, convective zone, photosphere, chromosphere and corona. Give the students six different colors of soft clay or modeling compound. Have them start with a small golf ball-sized sphere for the core, and layer additional coats of clay over for each of the remaining five sections. After the entire structure is complete, cut through the entire model with the edge of a large craft stick or plastic knife to reveal a cross-section view of each layer.