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In the 1850s, French physicist Jean Bernard Léon Foucault invented gyroscope by employing the conservation law for angular momentum to study Earth’s rotation. A gyroscope cannot stand erect and can only maintain balanced in rotation. It can also resist external forces that attempt to change its balance. Gyroscopes are used in all kinds of instruments that require sensing and maintaining directions. For example, it can be found in mobile phones. Moreover, it can also be found in space telescope and is a crucial instrument to explore space.