🌴A PalmDial🌴

Scene 1 – What time is it?

It is a bright and sunny day, and Jennie, Lisa, Mina, and Mark are walking their dogs, Toby and Ruby, after school. It is very hot outside so they decide to sit under a palm tree to relax for a bit. 

Jennie – (In an exhausted tone) Guys it’s getting very hot outside what if we take a break.

Lisa– Yeah! I also want to take a break!

Mina– Yeah, it has been a long day today. I had science and math tests. oof! 

Mark– Hey, what about our favorite spot, under the palm tree? 

Mina– (Nodding her head)  Ok, that sounds like a good place to sit. Come on, let’s go sit down.

(All four friends sit down under the palm tree by the twins’ house. Toby and Ruby play together like old friends.)

Lisa– (complaining) Guys we have been walking around for so long now. What time is it? 

Jennie – (looks around at the others) I don’t know, I don’t have a watch, what about you guys?

Mina – I don’t have a watch, Mark?

Mark– Nope, I don’t have a watch, nor my phone. I just went outside to run but met Mina on my way and started walking! I need to know the time because I have some homework to finish for Ms.Garcia’s class. There has to be something that tells us the time while we’re running, walking, or sitting outside. Many years ago, people didn’t have a watch to check the time or even phones. 

Mina – (Excited) Oh I know! The Earth rotates on its imaginary axis and the shadow “moves” (Mina makes a quotation signal with her hands) through the day. We can check the time using the sun. We can make a sundial. I learned about it in science class this week. 

Mark – Oh that’s right! Our science teacher explained it to us as well. We only need the sun and a pole.

Jennie– The sun?!!?!? How? What’s a sundial?

Lisa – (Shaking her head) Come on Jennie! We have one at our school!! That yellow circle in the middle of the field, by the playground. I am sure you saw it!

Jennie – I did, but I didn’t know what that was!

Mina – A sundial is a device that uses the sun depending on its position to tell time. We can see the sun’s apparent movement by using a line or point that casts a shadow on the dial plate underneath it. 

Jennie – Huh? I don’t get it. English, please!!

Mina – (Laughing) Let me explain myself better. Toby, go get me the stick! 

Toby – (Hands Mina a stick they use to play with)

(Mina grabs the stick and draws some diagrams on the dirt. She draws a circle with numbers and labels it as “Dial”. Then she buries the stick tilted in the ground right in the center of the dial.)  

Mina – This stick represents our gnomon. I know Jennie, I need to translate!!! (Smiling) The gnomon is the part of the sundial that makes the shadow on the dial. And the dial is where you can find the numbers and the shadows mark. 

Jennie – So does that mean I can check the time on the dial? 

Lisa – That’s my sister! (Lisa raises her hand up to high-five her sister. Jennie high-fives’s back)

Mark – I’m pretty sure one of the puppies will take the stick back so they can play, and bye-bye goes our little sundial. (In a sarcastic sad tone) 

Lisa – Well, why do you think we have this huge palm tree by our house? 

Everyone – (Together) The gnomon!

Toby and Ruby – (Jump around barking)

Mark – Ok guys, it seems to be getting late, meet you guys here tomorrow at the same solar time. 

Jennie – (Laughing) Solar time??? 

Mark – I’ll explain tomorrow. 

The girls – Bye Mark! Bye Ruby! 

(Walking back home, Mina and the twins come to an agreement.)

Mina –  Hey girls, what if we built our own sundial? We will need Mark’s help!

(The twins look at each other with an excited look on their faces)

Lisa– (In an affirmative tone) Sounds like a plan! 

Jennie – Sounds like someone will be very happy for the company! (

Jennie looks at Lisa and winks)

Mina – Stop Jennie! (Blushing) 

Jennie – I was talking about Toby!!!!

All three girls – (Laughing and waving to each other) See you tomorrow after school.

Toby – (Barks and jumps around)

Scene 2 – The Meridians Determine the Time

The next day all four friends go to the recreation center by their house. Mark and Jennie play some basketball while Mina and Lisa observe and walk the dogs. Mark and Jennie discuss the meridians using the basketball. 

Mark – (Walking towards the basketball court excitedly) Who’s ready to play a game?! 

Jennie – Ohh!! Me!! I am!!

Mark – (Looking at Mina and Lisa) What about you guys?

Mina– (Looking at Lisa) I think we’re good, we can watch you guys from the stands.

Lisa – I agree.

Mark – Ok!

(After Mark and Jennie play a couple more games they decide to take a break)

Mark – Oof, we’ve been playing for so long, no wonder I’m so tired. You?

Jennie – Yeah, let’s take a break?

Mark – (Exhausted) That sounds like a great idea!

(Both walk towards Lisa and Mina)

Mina – How was it?

Jennie – It was amazing, I won more times than Mark did!

Lisa – Only my sister! 

Mina – Lisa and I are going to take the puppies to the dog park. We’ll be right back.

Mark – Ok, see you guys later. And by the way, Toby and Ruby are not puppies anymore! 

Lisa– They will always be it for us!!!

(All laughing. Mina and Lisa walk toward the dog park with Toby and Ruby, while Jennie remembers the question she has for Mark)

Jennie – Anyways, Mark do you remember when you told me we would meet here at the same solar time? Can you explain it to me now?

Mark – Of course, solar time is different from the time that our watch shows.

Jennie – How is it different?

Mark – Well, solar time is the true time, and it depends on the local meridian. The time you see on the clock or watch is the official time and it depends on the time zone taken by the governments.

Jennie – What’s a time zone? What is a local meridian?

Mark – Woah, Woah one question at a time!! (laughing) Let’s start with the longitude lines or meridians. Longitude lines are imaginary lines that run up and down the globe. Like uh (Looks around for something to use as an example) Oh! This basketball, for example, see how the lines go from the top of the ball to the very bottom? Well, these lines are like the longitude lines on the globe. They are called meridians. 

Jennie – Woah, that’s so cool but, what does this have to do with time zones? 

Mark – Those lines are everywhere! One imaginary line is crossing you, right here in your head! (Mark draws an imaginary line on Jennie’s head) 

Jennie – And if I walk to my right two steps?

Mark – Another imaginary line will cross your head! (laughing)

Jennie – Very funny!!! (Jennie makes a funny face)

 Mark – Well now seriously, our country’s authorities take one meridian as a reference to set the official time for a whole country or a big area. In the USA we have 5 time zones. Each big area takes one meridian as a reference.  That’s why it is 5:00 pm in New York but 2:00 pm in Los Angeles at the same time!

Jennie – Wait then how is the solar time different?

Mark – In Florida and all the East of our country we use the meridian 75 or 60 but you are standing on the meridian 81. This is because the government chooses a meridian that is more convenient to accommodate a large area. It would be very strange to have one time at home and another at school. A sundial uses the local meridian though. 

Jennie – So, we are using one meridian and the sundial is using another?

Mark – Exactly, the one we use is pretty far from here, it is in the Atlantic ocean, but it helps us maintain one specific time instead of many at the same time in a selected area. 

Jennie – The solar time is real-time, and the clock time is not so real but is official so everyone around has the same time on their watches. 

Mark – You are correct, little girl!

Jennie – How does this affect our time, Mark?

Mark – Each degree of the meridians represents 4 minutes. The difference between the 81st meridian and the 75 is 6 degrees. 

Jennie – Got it! Six degrees multiplied by four minutes… (Jennie thinks out loud) four times six is 24. (screaming excited) Twenty-four minutes is the difference! 

Mark – You are close but there is another correction that needs to be done.

Jennie – One more? Which one Mark? 

Mark – We will talk about it tomorrow. (Mark looks toward the dog park) Here they come! (Mark waves to his two friends while they come closer and closer)

(Mina and Lisa walk back together and but Toby and Ruby happily run to show their affection to Mark and Jennie)

 Mina – Hi guys! Do you know what time is it?

Jennie – Solar or official?

Lisa, Mina, and Mark – Time to eat!!! (laughing and screaming)

Jennie – In that case, let’s move to another meridian!

(All four friends walk home talking and laughing)

Scene 3 – Is the Sun the Center of Our Solar System?

At Lisa’s and Jennie’s patio the four friends are eating a pizza and drinking smoothies. 

Lisa – Guys, why does the clock on the wall of the kitchen say it’s 8:00 PM when it’s so sunny outside? It’s supposed to be nighttime.  

Mina – Well, glad you asked! It is so sunny because we temporarily change our time zones. This is to save electricity, when it is bright outside you don’t turn on the lights, so you save electricity. It is called Saving Time.

Mark – It may not be temporary in Florida anymore, Mina! We might have saving time forever! Marcos Rubio’s bill to make daylight saving time permanent already passed the Senate.

Mina – True Mark, but it is not a law yet. The Sunshine Protection Act needs to pass by the House and be signed into law by President Joe Biden.

Lisa – So I can play with Toby outside when it is late the whole year!!! (All laugh)

Mina – Yeah, but remember that if we read the sundial we have to add an hour to whatever time it tells us, now not only in the summer but probably always.

 Mark – When we are not using the saving time, our reference is the meridian 75, but now is the 60. 

(Lisa runs inside the house)

Jennie – I know that we are in the 81 meridian and every degree stands for four minutes, so… (mumbling) eighty-one minus sixty is twenty-one, and times four is (screaming) eighty four!

Mark – An hour has sixty minutes so…

Jennie – (Jennie interrupts Mark with excitement) One hour and twenty-four minutes is the difference between the solar time and the standard time! We need to add twenty-four minutes in December but one hour and twenty-four minutes in April. That is a little bit crazy!!!

Mark – You are not done!

(Lisa comes back from the house with a paper in her hands and screams to all)

Lisa – And that is not all! There is another correction!

Mark – (Looks at Jennie and points at her with his finger)  Told you!

Lisa – The Time Equation! In this graph, we can check how many minutes we need to add or subtract from the standard time. 

Jennie – Why? Why do we need to use your Time Equation graph?  

Lisa – It is not mine! Since Medieval Time, astronomy included these studies.

And why? Because the earth revolves around the sun is not a perfect circle, but an ellipse. People needed it to calculate the time from a sundial. They didn’t have watches! 

Jennie – Oh my God! Poor people! (laughing) But wait, wait, wait, slow down a bit! I knew the Earth revolved around the sun but what do you mean by “ellipse”? 

Mark – An ellipse is an oval shape, it is like a large watermelon, we move around the sun in that way. That and the tilted axis of our planet cause seasons! The sun is also not in the center of our ellipse, that’s why not all of our days are 24 hours long. 

Jennie – (Using exclamation tone) Hold on! This is getting intense, how is that possible!  The sun is not in the “center” of our solar system? Our clocks all show 24 hours! (Mina put her two hands on her head)

Mina – 24 hours indeed, but that is an average because not all days are exactly 24 hours long, some days last 23.7 hours, or 24.9 hours. But imagine how weird it would be to have a different amount of hours every day! There would be a lot of confusion. That’s why people keep it to the average number of hours. 

Lisa – Do you guys want to know what the Time Equation correction is for today? (Lisa points to the paper that she brought from the house) Look here! On April 30th, this graph says that we need to subtract 3 minutes from the standard time to get the solar time.

Jennie – Ok, Ok! So If we know the standard time by just checking our watches we could know the real-time, I mean the Solar time! Am I right? 

Lisa – Did you guys notice how brilliant my sister is?  You are right Jen! Now we can check the standard time and calculate the Solar time or vise-versa!!!!

Jennie – Wow, those are some interesting reasons why solar time and standard time are so different. One hour and twenty-one minutes minus 3 minutes from the equation of time is? (Jennie looks to all three friends)

All three friends- One hour and eighteen minutes!!!

Jennie– Good Job! Now I finally understand!  

Lisa – Me too! (laughing)  I’m definitely telling Toby about this! (Laughs)

(They all walk inside the house)

Scene 4 – Local Latitude indicates the Gnomon’s angle. 

The next day, all four friends meet by the palm tree, their favorite spot. The twins ask some questions and they get right into building their new sundial.

Mina – (Meeting the twins at the palm tree) Hi guys how have you been?

(Toby runs up to Mina)

Jennie – We’ve been good, we have new questions!!!

Mina – And I have new answers!

(They all laugh)

Mark – (Walking with Ruby up to the group) Hey guys, are you ready for more learning? We are very close to building our sundial!!!

Lisa – Yeah! We all are!

(Toby and Ruby run-up to each other and start playing and barking)

Jennie –  Even Toby and Ruby are ready! (Laughing)

Mina – Sure!! Anyways, what were the questions you guys wanted to ask us? 

Lisa – Well, we want to know about latitude lines, in my science club my teacher told us that longitude lines are not the only lines on the globe. 

Mina – Well your teacher was right. The lines we call longitude lines or parallels are lines that run across the globe from east to west. The equator divides the planet in half, North and South. Parallels are like imaginary rings. Those rings are smaller the closer we get to the poles. Cool, right?

Jennie – Do we need to know about the latitude to build a sundial? 

Mina- Yes Jen, our local latitude is the angle of our Gnomon in the sundial. 

Mark-  The latitude is the distance from the Equator to this place. We can see it on Google maps. (showing his cell phone to the group) Check here! 28.38 degrees. 

Jennie – Okayyyyy, and now what can we do with that info?

Mark – Let’s go back to the gnomon. Do you remember it? The part that makes the shadow in a sundial? Well, the line of the gnomon that indicates the solar time must form an angle with the ground equal to the local latitude.  

Lisa – So, (Lisa takes the phone from Mark) May I have this mark? (She draws on the notes app) Our gnomon will be like a triangle, one side is the ground, forming a 90-degree angle with our beautiful palm, and (Jennie interrupts)

Jennie – Not too beautiful in your drawing! (laughing, Lisa continues ignoring Jennie’s comment)

Lisa- and the third side is the most important line! The one that tells us the time and it forms a little bigger than 28 degrees angle with the ground. 

Jennie –  Yeah! I always told you guys, my sister is a genius!!! Let’s build this sundial! Where do you want to put it? Here? (Jennie runs around the palm tree and stops every time to ask) Here? … Here?

Mark – Well, we have to find the true North first. 

Lisa – True north? Wait a second, I have a compass we can use!

Mina – The compass won’t do the job because it shows the “Magnetic North”.

Jennie – Magnetic north? What’s the difference isn’t there only one North?

Lisa- We need to go home now. We will talk about it tomorrow Saturday. We will have more time to hang outside and probably have some more progress if Jennie does take it seriously!!! (Lisa gives a “look” to her sister)

(The four friends go home. Jennie thinks aloud while walking home, the rest laugh) 

Jennie – North is North no matter what! And why do we need the North after all?

Scene 5 – Where is the Real North?

(Its Saturday morning and all four friends get together to finish the work they had started over the week)

Mina – (Walking towards the palm tree) Hey guys, how have you been?

Jennie – We have been good; I taught Toby a new trick!

Mina – Wait, now you have to show me!

Lisa – She taught him how to give high-fives! Look! (Lisa calls Toby and tells him to give her a high five. Toby jumps up and places his paw on Lisa’s hand.)

Mina – Awwww! He’s so cute! Let me try!

(Mina calls toby and asks him to give him her paw, again, Toby jumps up to give gives mina his paw.)

Mina – (Screaming) Oh my god I can’t! He’s so cuteeee! I HAVE to get a dog now!

Mark – (Walking up to the group) Wow that was a cool trick! Ruby can do that too! 

(Mark demonstrates how Ruby does her high fives. The girls all awe.)

Lisa – (Whispering to Mina) Are you sure you’re aweing at Ruby (Laughing)

(Mina ignores the comment)

Jennie – (Loudly) Guys you never finish answering my questions! I hate it when you leave me hanging! Now, remember how I asked what the difference between the true North and the Magnetic North is? Can I have some answers?

Mark – Well, the “True North” is the northern axis of rotation of the Earth. It is the point where the lines of longitude converge on maps. 

Jennie – Hold up you lost me! The True North is the what of the what of the Earth?

Mark – Let me make it easier, to find the True North you have to know a couple of things. First of all, did you know that the Earth rotates on an axis?

Jennie – Yeah, and what does it have to do with the True North?

Mark – Well, if you were to go to the north pole and stand directly in the center you would be on top of the axis. Now, imagine if you were to extend that line for miles and miles. Eventually, it will touch this little star known as the Pole Star. That star that tells you where the real north is.

Jennie – So the Pole star is always the north, then what is the Magnetic North?

Mark – The “Magnetic North” is the point on the Earth’s surface where its magnetic field points directly downwards.

Jennie – You’re doing it again, explain in English! English!

Mark – Ok ok ok, one more time, the Magnetic North is the one that you see on your compass, it works by when the magnetic force of our planet is pulling the magnets on the compass toward the center of the Earth.

Jennie – Ohhhhh, why didn’t you say that instead! (Laughing)

Lisa – I think he’s showing off how smart he is… (Looking at Mina)

(Jennie and Lisa both laugh while Mina gives them a dirty look, Mark stands there looking confused)

Lisa – Anyways, now that we know how to find the north let’s try and find it.

Jennie – But we need to wait until night! 

Mina – We could use an app on Mark’s phone to look for the North or Pole star. 

Mark – That’s true, let me find the app. 

(He finds the app and starts looking for the Polar Star.)

Jennie – (Excitedly) Wow that’s so cool! I see it, I see it!

Lisa– Yeah me too!

Mina – Now that we have found it let’s start to make our dial plate. 

Jennie – And a dial plate is?

Mark – A dial plate is the part of the sundial that tells you all the hours, like the face of the clock.

Lisa – So all we have to do is add the hours and boom were done! 

Mark – Nope! First, we need to make the gnomon and put it in the North-South imaginary line. We can actually find the real north by finding the 12 in the sundial! 

Jennie- The 12 in the sundial? Do you mean when the solar time is 12 o’clock? How do I know when it is going to be 12:00? 

Mark – You know Jen, You know the difference between the solar time and the standard time. We calculated it yesterday. Remember? 

Jennie- Right! One hour and twenty-one minutes!!! Ohhh! I got it!!! We need to wait until 1:21 PM on your phone so we can have the 12 in the solar time! Am I right? 

Mina – Yes you are!

Mark – So now we have to wait 21 minutes. It is 12:21 PM on my phone 

I will make a couple of calculations to determine the center of the sundial to start the gnomon there. If we know the angle is 28 degrees and the height of the palm could be marked at 2 meters, then the tangent of the 28 will give us the distance from the tree.  

Jennie – You do your high-level math, I’ll go get some spray paint I left at home to mark our 12 and a tape measure to create our gnomon! (Runs into the house to go get the spray paint and two tape measures that they had prepared the day before)

Lisa – And I will keep track of the time, meanwhile, (Excitedly) let’s clean the area! 

Mark, Mina, Jennie – Yeah!

Mark – (Mark calculates on his phone while mumbling) tan 28 = 0.5317;  2 divided by 0.53 is 3.76 meters. (screaming)I have it! We need to be 3.76 meters away from the tree. 

Lisa – Oh no! We have eight minutes left until it is 1:21! Quickly let’s go mark two meters on the palm! This is where the gnomon is going to be. (Lisa measures 2 meters with Jennie’s help and marks the tree by painting a ring around it at the height of 2-meters.)

Mark – The center of the dial plate will be at 3.76 meters from the palm in the North-South line. It means in the 12 o’clock shadow line. It is time. Do you see the shadow of the 2 meters height point on the ground? Mina please, hold the measuring tape on the palm here at the 2m mark. (Mina follows instructions) and Lisa please take the other measuring tape and hold it on the ground right here by the tree. (Lisa does what Mark said)

(Mark walks away from the tree in the exact opposite direction of the shadow of the palm tree with the two measuring tapes forming a triangle. He stops when the button tape measures 3.76 meters) This is the center of our sundial! Jen please draw and x here on the ground! (Jennie followers Mark’s instructions with a solemn face, like in a very important mission) You all can see that the shadow of the top tape is on the button tape. That is the north-south line and also the twelve o’clock on the sundial.

Mina – (Mina paints a line from the root of the palm with the X that Jennie drew on the ground)  Ok, this is our 12 solar time, let’s mark the rest of the times. Now we can find the 6:00 AM and 6:00 PM by tracing a line perpendicular to the twelve-line through this X. 

Mark– Let’s measure 3.76 meters to the left and to the right of the X. (Mark traces the lines with the white paint) Now we have 6:00 AM and 6:00 PM solar time. 

Jennie – Wow it’s starting to look like a sundial! I cant wait to see what it will look like when it is finished! 

Mark – It will look amazing when it is done! (In an affirmative tone) I know it!

Mina – We may continue tomorrow. The hardest part is already done!