#lesson plan

HW Due Mon:

Open https://mysolartime.com/ in a new tab and allow the website to track your location.

Open https://www.utctime.net/ in a new tab.

Reblog this post the current UTC time and your local time, using the following format:

21:00 UTC, 4:00 local

4. Vote in the following poll.

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Social Studies, Grade 5, Geography 6.1.5.GeoSV.3: Demonstrate how to use digital geographic tools, maps and globes to measure distances and determine time zones, and locations using latitude and longitude.

Do Now:

Provide students with a paper copy of a population density world map and 2 minutes to fulfill the following instruction:

Draw lines on the map in order to separate the world into 24 time zones. Try not to separate dense population centers into different time zones.

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Class Discussion:

Use the projector to share and discuss the maps of any students who are willing to share. Have fun with this, there are bound to be some good ideas and bad ideas because 5th grade is like that.

Then, project the official world time zone map, and discuss the good ideas and bad ideas present here.

Exemplary discussion points:

The 0-point of the timezone map is the Prime Meridian, which cuts right through England. Why do you think it's in England?

How come some countries like the US and Brazil are cut into multiple time zones, but China isn't?

Why do you think the lines are pretty straight in Europe, Africa, and North and South America, but so confused in Asia and the Atlantic and Pacific Oceans?

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Direct Instruction:

Long ago, nobody really cared about the exact time. All you really needed was sunrise, sunset, and noon, and you could figure those out with your eyes. If you wanted to be fancy, you could put a stick in the ground and trace its shadow over the course of the day to measure out hours.

Perhaps the first recorded complaint of time-keeping technology comes from Rome in 250BCE.

The gods confound the man who first found out how to distinguish hours! Confound him too Who in this place set up a sundial To cut and hack my days so wretchedly Into small portions! When I was a boy, My belly was my sundial: one more sure, Truer, and more exact than any of them. This dial told me when it was time To go to dinner, when I had anything to eat; But nowadays, why even when I have, I can't fall-to unless the sun gives leave. The town's so full of these confounded dials, The greatest part of its inhabitants, Shrunk up with hunger, creep along the streets. [x]

In other words, "Kids these days are always looking at their sundials. Back in my day, there were only three times, Breakfast, Lunch, and Dinner. All we needed to tell the time was our stomach!"

Please note this was a satire, so if it sounds funny, you are correct.

But for 18th century British sailors, accurate timekeeping was no laughing matter. These sailors used fancy math (called trigonometry) to calculate their latitude. So long as they knew the angle between the sun and the horizon, and the time when that angle was measured.

Ship's captains would keep logbooks of these measurements. That way, another ship's captain would be able to reference the logbook in order to replicate the journey, much like replicating a science experiment.

Now... think about this... how can you do that unless the next captain is using the same time as you. We take this for granted today, but how can you be sure that two clocks are synchronized?

Scientists in the town of Greenwich, England (pronounced gren`-ich) recorded the solar noon every day of the year and calculated the Greenwich Mean Time. By keeping an accurate and exact time in one exact place, GMT eventually the Coordinated Universal Time (UTC) for everyone in the world. That's why in the time zone map, the 0 runs through one specific part of England.

This is important. For the first time in human history, the clocks in different places were synchronized. Solar noon happens at a different time in London than it does in Greenwich, but if they both use GMT (otherwise known as UTC), then they can coordinate their schedules. This was very important for railroads, where exact, coordinated schedules are very important.

Soon, the entire country of England existed within a single time zone.

When the United States built railroads that spanned vast lateral (East-West) distances, they needed to create different time zones for cities that were far apart from each other, such as New York and Chicago. Thus, the US became the first country with multiple time zones.

As the rest of the world industrialized, they needed to pick their time zones. You can see this on the map. Each time zone is, at least in theory, as wide as 1/24 the circumference of the Earth. It's like the space between the numbers on a clock! Most countries are smaller than this, so they can comfortably fit within a single timezone. Others, like Brazil and Australia, divided their landmasses into two or three time zones.

China did not have widespread industrialization until post-WWII dictatorial communist rule. This was a very uncaring and inconsiderate government, to put it mildly. Suffice it to say that for Chinese farmers in the far west, having to get up 2-3 hours earlier every day would have been the least of their worries.

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Modeled Activity:

Show students how to use this Day and Night world map as a way to visualize the day and night cycle across the world.

Additionally, show them how to use https://mysolartime.com/ to find their current time where they live.

Give students a moment to calculate the difference between their Local Time and the official time in their time zone, and what that means.

(I am currently in Philadelphia, which is 11 minutes East of New York City)

Finally, show students how to use https://www.utctime.net/ to find their exact, current UTC.

Have students calculate the difference in minutes and hours between Local Time and Official Time.

00:41 - 19:30 = -5:11 (Philadelphia is 5 hours and 11 minutes East of Greenwich, England)

Explain that every internet connected device in the world uses a service like this one, then adds or subtracts hours to fit the time zone of your current location.

Higher Order Learning:

Students work in small groups to look up the local time in different major cities around the world, recording their data on a worksheet. As they do, they should discuss the following questions:

Are time zones still relevant in our always-online society?

If you can know your Local Time and the UTC any time you look at your phone, then what purpose do time zones still serve?

How would it feel for schools and businesses to use UTC instead?

How would you feel if your school day went from 4:20-10:50 UTC?

Finally, each student must individually write at least 3 sentences responding to the following question:

Essential Question: How can basic calculations of percent change influence major world events?

Do Now: Calculate the percent increase or decrease in each of the following equations. x = (28 - 17.9)/28 x = (41.5 - 57.7)/57.7

Class Discussion: Remind students about how to perform basic calculations of increase/decrease factors. Ask them whether this calculation would be more complicated if the quantities were dollars instead of just numbers (answer: no). Ask them whether this calculation would be more complicated if the quantities were billions of dollars instead of just dollars (answer: no). Show students that they just performed the exact same calculations that Donald Trump did in order to decide what tariffs should be put upon Indonesia and Thailand, respectively.

Finally, ask students whether important global trade decisions should be calculated with 7th grade math skills, or if perhaps this is insufficient given the severe consequences that could arise from such a dunning-kruger error.

Direct Instruction: Explain what a Dunning-Kruger error is, if for no other reason than to communicate how absolutely maddening has it is for legitimate experts who have dedicated their lives to nudging fiscal policy in the right direction and then watch as their president makes the worst decision possible on purpose.

Take a moment to explain the difference between an import and an export, so that students understand what these billions of dollars actually mean in the real world. Feel free to call out anyone who has ever questioned whether or not they would ever use this kind of math in the real world. Show them that it's happening right now, and make sure they understand how terrifying that is.

Acknowledge the variables: x: total exports from US to country i m: total imports to US from country i tau (τ): calculated % tariff on all imports to US from country i epsilon (ε): elasticity phi (φ): passthrough

Ask students what they think elasticity and passthrough mean, then show students this passage from ustr.gov:

Parameter Selection To calculate reciprocal tariffs, import and export data from the U.S. Census Bureau for 2024. Parameter values for ε and φ were selected. The price elasticity of import demand, ε, was set at 4. Recent evidence suggests the elasticity is near 2 in the long run (Boehm et al., 2023), but estimates of the elasticity vary. To be conservative, studies that find higher elasticities near 3-4 (e.g., Broda and Weinstein 2006; Simonovska and Waugh 2014; Soderbery 2018) were drawn on. The elasticity of import prices with respect to tariffs, φ, is 0.25. The recent experience with U.S. tariffs on China has demonstrated that tariff passthrough to retail prices was low (Cavallo et al, 2021).

Ask students if this clarified anything about what elasticity and passthrough mean. Most will say "no", but if anyone points out that multiplying 4 by 0.25 cancels them both out, reward them. That student is correct, because elasticity and passthrough have been arbitrarily assigned so as to make this calculation so simple that even Donald Trump can understand it.

Modeled Learning: Show how to apply these tariffs to popular imports such as raw coffee beans. For example, the USDA report of coffee imports from 2024 (page 6) shows that the vast majority of raw coffee is imported from Brazil.

A simple search with Perplexity.ai tells us that in 2024, imports (m) = $42.3 billion and exports (x) = $49.7 billion, so the reciprocal tariff would be (x-m)/m = (49.7-42.3)/42.3 = 17.5%.

Thus, all coffee imports from Brazil will automatically be 17.5% more expensive.

Be sure to highlight that this is happening to every country in the world, even those with total populations less than 1000.

Higher Order Learning:

Students should consider the following facts:

There is very little territory within the United States that can grow coffee.

Almost all coffee in the world is grown within what is called "The Global South", where the climate is warm and the labor is cheap.

The US exports significantly more (sometimes vastly more) to countries in the Global South than we import from them.

Students should then answer the following questions:

What will this universal tariff calculation do to the price of coffee?

Is there any way that US coffee companies can import the same amount of coffee as before without passing on the cost to consumers? Why or why not?