Sam and Loretta saw a cool experiment on TV and wanted to try it on their own. First, they poured sand into a plastic cup until it was half full. Next, they used a thermometer to take the sand's temperature. They then taped a cup upside down on top of the cup with sand in it. Sam and Loretta took turns shaking the cup. They shook it 100 times, un-taped it, and took the sand's temperature. The temperature was 10 degrees C. They re-taped it, shook it 500 times, un-taped it and took the sand's temperature. The temperature was 15 degrees C. They re-taped it, shook it 1000 times and then un-taped it and took the sand's temperature. The temperature was 20 degrees C. 1. What was the Independent Variable for this experiment?