After completing two experiments to find the shear modulus of a beam, I found two very different results. For test 1, we twisted the beam slowly at very small angles (0.005 - 0.03 rad), only in its elastic form. The torque was found using a torsiometer . In test two a replica of the beam was used and twisted till breaking point (1 - 1274 degrees). Here the results were found using a digital load meter. However the torque, even for lower angles was much less in test 2 than test 1, even though the same method of twisting was used. For the steel beam G was 106GPa in exp 1 and 60 in GPA. Would anyone know why there is such a difference.