Physics help---Sources of errors and limitations Two sources of errors and limitations for Eiffel tower lab to prove that it expands in the summer when it is heated and it contracts in the winter when it cools. Here is the procedure for the experiment i designed: 1. Attach a fixed stick to the tip of the tower and attach the string to the end of the stick. 2. Attach the rubber band to the other end of the string that ends right at the surface of the ground. 3. Mark a point unto the rubber band about 1 meter from the ground. 4. Measure the Eiffel tower in the winter and record your results. 5. Return in the summer and measure it again. If there is a gap between the rubber band and the ground and the point marked has gone above or below a meter then it is proven that the Eiffel tower has expanded. Record your results. Two sources of errors for center of gravity of an irregular shaped object lab: Two sources of errors and limitations for fluid and pressure lab. this lab is to prove that fluid and pressure varies with the size of the opening(hole) Any help anyone? Please?