Revision Notes for Class 7 Science Chapter 8: Measurement of Time and Motion

Quick revision notes summarizing all key concepts from Class 7 Science Chapter 8 “Measurement of Time and Motion”. These Class 7 Science Chapter 8 notes are ideal for quick revision just before exams.

• Before mechanical clocks, time was measured using sundials, water clocks, hourglasses, and candle clocks.
• Speed = Distance ÷ Time. It tells us how fast an object is moving, and allows fair comparison between motions covering different distances or taking different times.
• Speed unit conversion: to convert km/h to m/s, multiply by 5/18. To convert m/s to km/h, multiply by 18/5.
• Uniform motion: an object covers equal distances in equal intervals of time (constant speed).
• Non-uniform motion: an object covers unequal distances in equal intervals of time (changing speed) – this is the more common type of motion in everyday life (e.g., traffic, sports, walking through crowds).
• Average speed = Total distance travelled ÷ Total time taken. This applies even when the motion is non-uniform.
• To find a required speed for a remaining distance/time in a multi-part journey, use Speed = Remaining distance ÷ Remaining time.
• Real-world timetable data (like train schedules) can be used to calculate speed between any two points using the standard speed formula.

NCERT Solutions: Class 7 Science Chapter 8
Extra Questions: Class 7 Science Chapter 8

For the full chapter, see the Class 7 Science book page and the Class 7 Science Formulas Handbook.

Written by Satish

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