测量出来的磁感应强度随时间变化规律不同.只有最大摆角小于1°时，单摆才可看作简谐振动.不同最大摆角的磁感应强度随

时间变化曲线可以用磁偶极子模型结合大角度单摆公式来描述.利用磁传感器测量的当地重力加速度为9.868m/s2，由于磁性

摆空气阻尼较小，测得的实验误差仅为0.8%.

pendulum based on the Phyphox APP. The results showed that the behavior of magnetic induction with time varies

with different amplitude angles. Only when the amplitude angle is less than 1°，the simple harmonic vibration of the

simple pendulum could occur. The curve of magnetic induction via time at different amplitude angles can be described

by magnetic dipole model combined with large angle pendulum formula. The local gravity acceleration measured

by the smartphone magnetic sensor is 9.868 m/s2 . Due to the small air damping of the magnetic pendulum，the

experimental error is only 0.8%.