Photography lesson

Lesson of the day: “Get ready for the new improved second”

Featured Article: “Get ready for the new improved secondby Alanna Mitchell

What exactly is a second of time? Who invented it? How do you know that a second on your watch is the same as someone else’s on the other side of the world?

Right now, scientists are getting ready to redefine the fundamental unit of time. The second will not be longer or shorter, but it will be more precise and much more powerful.

In this lesson, you will discover the history of time reading, metrology and why a new definition of the second is on the way. Next, you’ll create a children’s book explaining the second, minute, hour, and day to a third-grader.

Part 1: A world without clocks

Imagine a world without clocks or a way to tell the precise time. How would the world be different? How would this affect your life – on a large and small scale?

For example, how would you know when to get up in the morning? When would the third period be? When should the ball fall on New Year’s Eve?

Take a few minutes to picture this world to yourself. Then make a list of 10 ways things would be different without clocks. (Keep in mind: your list items can be big or small, personal or global.)

Then find a partner and share your lists. How are they similar? How are they different? Would you like to live in a world without clocks? What would be the advantages and disadvantages of this imaginary world?

Part 2: What is a second, really? Write a definition to explain it.

How long is a second? How would you define it? More importantly, how would you get two people to agree on how long a second is if neither of you had a clock, stopwatch, or timing device?

(You might be wondering what the exact time is, but let’s save that question for another day!)

Take the time to think about what a second really is. Then come up with a definition. How could you explain the concept of a second in simple language that a third grader would understand?

Finally, share your definition with a partner or the class: who is more accurate and why?

Read featured articlethen answer the following questions:

1. The article begins thus: “Modern civilization, it is said, would be impossible without measure. And measurement would be useless if we didn’t all use the same units. Do you agree? Explain the significance of these opening lines and what evidence from your own life and education might support his claims.

2. What is the International Bureau of Weights and Measures (known by its French acronym, BIPM)? What seven basic units does it regulate and why? Why is the organization constantly refining the standard units?

3. The article provides a rich history of how humans told the weather. Which method from the past was the most fascinating, surprising or memorable for you? Were any of these methods similar to those you suggested in the warm-up activity?

4. What was wrong with the pre-1967 method of basing the second on the rotation of the Earth, according to the article?

5. Why is a new redefinition of the second in preparation? Explain how optical atomic clocks work and why they can measure time more accurately.

6. Take a close look at the photographs in the article: What story do these images tell about how we define and redefine time? What stood out to you and why?

seven. Does reading the article change your perception of time or seconds? Are you more interested in metrology – the science of measurement and its application? What was most fascinating, surprising or memorable? What questions do you still have about metrology or seconds?

Using your brainstorming from the warm-up activity, write and illustrate a children’s book that explains what a second, a minute, an hour and a day are. Be sure to explain how we calculate these numbers, why it’s important to have a standardized definition, and what difference these measurements make in our lives. Use interesting and relevant vocabulary and examples for young children.

You can hand draw or paint your original story or use one of the free book-making apps, like MyStorybook, BookBildr, or Storybird.

You can contribute what you have learned about how humans have told time through history from the featured article or do additional research using one or more of the following articles or videos:


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