If the experiment tests what heats faster water or sand and the materials are water, sand, cups, thermometer, and a lamp, what would the dependent and independent variables be? Thanks!

You are travelling on a long non-stop flight from tahiti to tampa. you have been in the air for about 7 hours and have not moved, since you boarded the plane at tahiti. you need to use the rest room and on standing up feel dizzy. the best explanation for your dizziness