Ascientist used a laboratory model to test the effect of radiation, or the sun, in heating land and water on earth. to do this experiment, 200 ml of water and dry sand were placed in to 2 separate 250-ml beakers. each beaker was then placed under the same lamp. temperature readings were taken of each substance every 2 minutes for 8 minutes. use the data table to answer the following questions. substance heated starting temp (°c) 2 min 4 min 6 min 8 min water 18 18.5 19.5 21 22 dry sand 18 20 22 24 26 identify the manipulated variable and the responding variable in this experiment. explain your reasoning.