Follow the directions below and then answer the questions: 1. Measure the area of the calculator's solar cell. 2. Turn on the calculator. Make sure there is enough light for the calculator to work. 3. Gradually cover the solar cell with the index card. 4. Observe the calculator's display as you cover more of the cell. 5. Measure the uncovered area of the solar cell when the calculator no longer works. 6. Record the area left. Questions: 1. How much of the solar cell is needed to keep the calculator working? 2. Why might a solar calculator have a solar cell that is larger than necessary?