The document describes an activity to classify materials based on their ability to absorb water. Students are instructed to observe samples of various materials and record their observations in a data chart about how each material looks before and after adding water, and whether it absorbs water or not. The objectives are to describe materials based on their ability to absorb water and classify them into groups. Materials like sponges, cotton, and towels are expected to absorb water while materials like styrofoam and plastics are expected to not absorb water.