1 page reading passage that explains why the ocean is salty, average salinity measurements for fresh and salt water, and factors that increase and decrease salinity in ocean water (evaporation, ice formation, freshwater runoff, ice melting, & salinity gradients) Student response on page 2 has a chart with 5 illustrations depicting scenarios that increase or decrease salinity. Students are asked to explain what is happening in each illustration. Ready to print! PDF is the paid download; a link