1. Unit 1E – Time (Textbook - p.47)

2. When is time important in our daily lives?

4. http://www.youtube.com/watch?v=nt38AsO7eXQ&mode=related&searchhttp://www.youtube.com/watch?v=nt38AsO7eXQ&mode=related&search= http://www.youtube.com/watch?v=_OiEgAwSd_o

6. How is time measured in daily life?

7. In daily life, we use the following items to measure time. Watch Clock Stop-watch

8. How did people measure time in the past?

9. In the past, people measured time by using…. Hourglasses

10. Sundials

11. Water Clock

12. Experiment 1.10 Objective: To use a stop-watch to measure time intervals Materials and apparatus: watch or stop watch Steps: 1. I will ring a bell. Start counting seconds in your mind as soon as I ring the bell. Stop counting immediately when you hear the bell again.

13. Results: *Your estimated time interval is _____________s. *The time intervals estimated by any two of your classmates: _____________________________ *The longest estimated time interval in class: __________s *The shortest estimated time interval in class: _________s *Your teacher will give you the correct answer: ________s Conclusion / Reflection: Can you measure time accurately by just counting in your mind?

14. Experiment 1.1 Objective: To use a stop-watch to measure the pulse rate Materials and apparatus: stop-watch Steps: Part A 1.Press three fingers on the wrist of your left hand and find the pulse. 2.I will tell you to start counting your pulse. Results: -Your normal pulse rate is _____________beats per minute. -The highest pulse rate in class is _______________beats per minute. -The lowest pulse rate in class is _______________ beats per minute. Conclusion / Reflection: How can you obtain a more reliable measurement of your pulse rate?

15. Steps: Part B 1.Do jogging in the same place for two minutes. 2.Measure your pulse rate again. Result: Your pulse rate is now _______________ beats per minute. Conclusion / Reflection: Why does your heart beat faster after jogging for two minutes?

16. AgeNormal heart rate (beats per minute) Newborn130 3 months150 6 months135 1 year125 2 years115 3 years100 4 years100 6 years100 8 years90 9 years95 12 years85 Adult60-100 Some interesting facts about heart beats!

17. What have we learnt today? Today we have learnt…. -the importance of time in our daily lives -how the time is measured nowadays -how the time was measured in the past -counting in mind is not an accurate way to measure time -the importance of time in measuring our pulse rate/ heart beat

18. Homework - Textbook: Read P.43 – 45 Next time we will do experiment 1.9 (Using a measuring cylinder to measure volumes). Browse through the steps and make sure that you have a basic idea of what you have to do for the next experiment.