Name the device whose periodic motion was used for making clocks till recently.

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for a device that exhibits periodic motion and has been used for making clocks until recently.

2. **Identifying the Device**: The device that fits this description is the "Quartz Crystal." Quartz crystals are known for their ability to oscillate at a specific frequency when subjected to an electric field.

3. **Periodic Motion of Quartz Crystal**: Quartz crystals exhibit periodic motion due to their natural resonance frequency. This means they can vibrate back and forth in a regular pattern.

4. **Application in Clocks**: The periodic motion of the quartz crystal is utilized in clocks to keep accurate time. When the quartz crystal vibrates at its specific frequency, it generates a consistent signal.

5. **Accuracy and Precision**: The frequency at which the quartz crystal oscillates helps to enhance the accuracy and precision of the clock. This is because the regularity of the vibrations allows for a reliable timekeeping mechanism.

6. **Conclusion**: Therefore, the device whose periodic motion was used for making clocks until recently is the "Quartz Crystal."

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