Creations related to Sun, Earth, Moon and other planets in the solar system and related events.
Sun Earth Moon Model
3D Printed Model - Sun, Moon and Earth
3. Inner Planets
Phases of moon
5. Zero Shadow Day - 2022
6. Same side of Moon
7. Uttarayan and Dakshinayan - Northward and Southward Movement of the SUN
8. Umbra / Penumbra
Movement of Shadows - clockwise or anticlockwise
How can I make use of toys as a medium to understand concepts in our textbook ? This one question led me to my exciting journey in the world of automata toys, which started around a year back. Here is what I learnt so far.….
Toys are fun, and fun is important ! By definition, toys are for children but they can also be for adults. Automata, also known as mechanical toys, have universal appeal which transcends all ages. Fascination lies in a simple automated movement, whether the mechanism is hidden or revealed.
Automata toys are “story telling mechanical sculptures”. These are child-tailored communication devices, much appreciated by the children and easy to realize in the classroom. These whimsical and wonderful machines combine art, play, humor, science and engineering. Automata toys are complete units that typically tell a short story—someone chopping wood, a horse running, men fishing, etc. They utilize a combination of levers, cranks, linkages, cams, shafts, ratchets, gearing, and drives. Building automata toys is a good example of integrating science and art with an activity. For learners, the narrative and decorative aspects are as important as the mechanical elements. It is an involved process that has a lot of potential for stimulating the imagination of students and providing a fun, practical learning platform.
The Automata toy consists of two parts: its top features and an underlying mechanical assembly. In the mechanical part, simple machine elements like cams, levers and linkages are used in a playful way. Features are brought to life with the help of paper figures, colors and other craft ideas.
Keywords like creative thinking, verbal and non-verbal communication, adaptability, choice-making and more came to life in the automata workshops I conducted with teachers as well as students. Participants are guided to design and build their own automata using everyday material like corrugated sheet, sticks and straws.
Typical introductory session on this topic lasts for 2-3 hours in which participants work in teams. To begin with, the team discusses an event, process or abstract concept to work on. Lots of ideas are discussed and debated during this phase. Once an idea is finalized, the team comes up with a short story. Students choose stories based on animals, sports, hobbies or festivals while teachers try to choose concepts from the textbook. Story dictates how automata toy will come to life. Some parts of the story represent static parts while other parts are candidates for movement. Action verbs shortlisted from the story will drive the movement of automata toy.
It is said that a picture is worth a thousand words. Drawing a picture of an automata toy and related mechanism is the most important step in the whole process. Team members can express their ideas in a better way through pictures. Some gaps are also identified at this juncture. Picture or schematic of the toy gives team members an opportunity to communicate how they feel about the construction process to be followed. In some instances, teams chose different action verbs as the selected one seemed too difficult to build.
With a rough blueprint of the toy ready, the team gathers input material like a box of corrugated sheet, wheels made from foam sheet, kebab sticks and thick paper. Members having inclination on the art side take up work like character drawing, cutting and painting. Others start connecting wheels, axles and the related motion part. Individual contribution in the area of one’s choice can be seen in this phase. Any creative work involves challenges, difficulties and rewards. Building automata toy step offers these in abundance. Team normally goes through a couple of iterations before the automata toy comes to life. Many times it is only half done for want of time but joy of achieving part of the functionality is none the less visible.
In many instances, teams collaborate with other teams as well to learn from their creations as well as offer help in fixing things for others. Towards the end of the workshop, it's fulfilling to see your working automata toy placed next to the other toys. Participants enjoy the process more than the final automata toy itself. Many feel that making automata toy is not a very easy process which they initially thought but it is a satisfying and rewarding thing to do, especially when it finally works !
There is much more to learn and do in this field. Difficult to understand concepts in the textbook can be taken up as a theme for Automata toy. This automata toy can complement as a teaching aid in the classroom. Static models created by students as a part of a project can be brought to life by adding motion in the same. Automata building activity allowed students to tinker with lots of things, guided by whim, imagination and curiosity. While tinkering, there are no instructions - but there are also no failures, no right or wrong ways of doing things. It's all about figuring out how things work and reworking them.
Note : Creations done by students and teachers are available at the following URL
https://tinyurl.com/automatatoys
Experimentation is a critical aspect of any science education. Smartphone can be an effective teaching aids in this journey. Concept clarification activities can include data feeds from various sensors in smartphone.
Gathering data and analyzing the same forms a key phase in any enquiry based activity. Many smartphone apps help students with these phases.
More than 40 physical measurements are possible with the sensors available in smartphone.
In an earlier video, we explored the movement of earth and moon with respect to the SUN.
Red ball representing the sun can be replaced with the flashlight of the cell phone. Now we can observe the play of shadows as Earth and Moon change positions. This arrangement does not allow us to view the moon from Earth. Let us place another phone in place of earth and a larger ball in place of a small moon.
In fact we don't need this setupl. Instead, we will use the flashlight of this phone to represent sunlight.
On this turntable made from corrugated sheet, a small plastic ball represents the moon.
This second phone represents Earth. Camera on this second mobile phone will enable us to view phases of the moon as it revolves around the Earth.
Height of the light source needs adjustment at some locations to avoid the shadow of Earth on the moon.
Let us start with the New Moon.
For better viewing, we will move the flashlight farther.
Frame on the left side shows the top view while the frame on the right side shows the moon as seen from Earth.
Like Earth, the Moon has a day side and a night side, which change as the Moon rotates. The Sun always illuminates half of the Moon while the other half remains dark, but how much we are able to see of that illuminated half changes as the Moon travels through its orbit. We call it a Phase.
The Moon has eight phases in a lunar month: four primary and four intermediate phases.
There are eight phases. in order, new Moon, waxing crescent, first quarter, waxing gibbous, full Moon, waning gibbous, third quarter and waning crescent. The cycle repeats once a month (every 29.5 days).
New Moon
This is the invisible phase of the Moon, with the illuminated side of the Moon facing the Sun and the night side facing Earth. In this phase, the Moon is in the same part of the sky as the Sun and rises and sets with the Sun. Not only is the illuminated side facing away from the Earth, it’s also up during the day! Remember, in this phase, the Moon doesn’t usually pass directly between Earth and the Sun, due to the inclination of the Moon’s orbit. It only passes near the Sun from our perspective on Earth.
Waxing Crescent
This silver sliver of a Moon occurs when the illuminated half of the Moon faces mostly away from Earth, with only a tiny portion visible to us from Earth. It grows daily as the Moon’s orbit carries the Moon’s dayside farther into view. Every day, the Moon rises a little bit later.
Waxing Gibbous
Now most of the Moon’s dayside has come into view, and the Moon appears brighter in the sky.
Full Moon
This is as close as we come to seeing the Sun’s illumination of the entire day side of the Moon (so, technically, this would be the real half moon). The Moon is opposite the Sun, as viewed from Earth, revealing the Moon’s dayside. A full moon rises around sunset and sets around sunrise. The Moon will appear full for a couple of days.
Waning Gibbous
As the Moon begins its journey back toward the Sun, the opposite side of the Moon now reflects the Moon’s light. The lighted side appears to shrink, but the Moon’s orbit is simply carrying it out of view from our perspective. The Moon rises later and later each night.
Last Quarter
The Moon looks like it’s half illuminated from the perspective of Earth, but really you’re seeing half of the half of the Moon that’s illuminated by the Sun ― or a quarter. A last quarter moon, also known as a third quarter moon, rises around midnight and sets around noon.
Waning Crescent
The Moon is nearly back to the point in its orbit where its dayside directly faces the Sun, and all that we see from our perspective is a thin curve.
Variations.
You can perform this activity with balls of different sizes, changing the position of the SUN as well.
Do try this at home.
I captured phases of the moon with my camera during this activity as well.
Ball with indentations was 3D printed for this activity.
Thank You.
Let us understand more about this calendar with the help of a model.
In earlier videos, we explored key events associated with the Sun, Earth and Moon.
Relative locations were discussed as per Gregorian calendar as well as Hindu Calendar.
In this video, let us explore one more calendar, India’s National Solar calendar.
We will focus on the movement of Earth and Sun during a span of one year and arrangement of months related to the same.
Months of Gregorian calendar are listed on the outer rim like this.
January, February, March, April and so on …
Unlike the Luni-solar based Hindu Calendar, the National Solar Calendar is based on the movement of Earth around the SUN.
1st day of this calendar starts on the Vernal Equinox, when days and nights are equal.
This day happens to be the 22nd March of the Gregorian Calendar.
There are twelve months of the National Solar Calendar.
They are named as
Chaitra,
Vaishakh
Jeshtya
Aashadh
Shravan
Bhadra
Ashwin
Kartik
Agrahayan
Paush
Magh
Falgun.
First month of Chaitra has 30 days while the next five months marked in Green have 31 days.
Remaining months marked in yellow are 30 days each.
Each month has a fixed start date associated with the Gregorian calendar.
Chaitra starts on 22nd March.
Vaishakh starts on 21st april
Jeshtya starts on 22 May
Aashadh starts on 22 June
Shravan starts on 23 July
Bhadrapad starts on 23 August
Ashwin starts on 23 Sept
Kartik starts on 23 Oct
Instead of Margshirsh, this month is called Agrahayan and starts on 22 Nov
Paush starts on 22 Dec
Magh on 21st Jan
And Falgun on 20th Feb.
All months together account for 365 days.
When there is a leap year. Chaitra has 31 days instead of 30 and starts on 21st March of Gregorian Calendar.
Sun spends more time in the Northern Hemisphere hence these months are 31 days each.
Now let us view the position of Earth’s axis from the front side.
On 21st March, Start of Chaitra month, both hemisphere receive equal amount of light. - Equinox.
On 22nd June, Earth’s axis is tilted towards the sun. Days are longer and nights shorter in Northern Hemisphere. This day is also the first day of Aashadh.
Dakshinayan starts from this date as well.
On 23rd September there is another equinox. This is also the start of Ashwin Month.
On 22nd December, Earth’s axis is tilted away from the SUN. This is also the start of Paush month.
How about seasons.
National solar calendar has identified six seasons associated with 2 months each.
Grishma - Summary - Vaishakh and Jeshtya
Varsha - Rainy Season - Aashadh and Shravan
Sharat - Autumn - Bhadra and Ashwin
Hemant - Kartik and Margashirsh or Agrahayan
Shishir - Winter - Paush and Maagh
Vasanta - Spring - Falgun and Chaitra.
Sun spends more time in Northern Hemisphere than Southern Hemisphere. hence these months have 31 days
Sequence of the year is as per the Shalivahan Shak.
More information is available on the website https://www.rdpm.in/ as well.
In the previous video, we explored events associated with the movement of Sun, Earth and Moon.
Let us understand how months of the Hindu Calendar are decided with the help of this model. Though Hindu Calendar is based on the cycles of the Moon, it tries to accommodate solar year as well in single framework. This is done by adding 'Adhik Maas' or extra month every 33 months.
Months familiar to us are as per Gregorian Calendar which is based on Solar Cycle.
Earth takes 365 days to complete one revolution around the Sun.
These are divided into 12 parts and each part is called Month.
Some months have 31 days while some have 30 except February which has 28 or 29 days.
Position of Earth along the orbit is also decided like 21st March, 22nd June, 22nd September and 22 December.
Months in Hindu calendar are based on the cycles of the Moon.
Time taken by the Moon to complete one revolution from New Moon phase to next New Moon is considered as one month in Hindu Calendar. Also known as ChandraMaas .
On this dial, Zodiac signs as per the Hindu Calendar are named like this. Mesh, Rishabh, Mithun, Karka,... popularly known as Rashi as well.
Just like Gregorian Calendar, there are 12 months, Chaitra, Vaishakh, Jeshtya, Aashadh.......
While months are named as Chaitra, Vaishakh, Jeshtya, Aaashadh, Shravan ....
Let us start with Gudhipadva - Festival which marks start of New Year.
Let us take help of the calendar to learn about the same.
Month is April and Year 2021.
There is New Moon or Amavasya on 12th April. Let us position the moon accordingly.
When Sun is in MEEN Rashi , First Month Chaitra starts from the new Moon phase that is amavasya.
13th April is the first day of Chaitra also known as Chaitra Pratipada.
There is a full moon or Purnima on 27th April and Amavasya or New Moon on 11th May, marking the end of first month Chaitra.
Each Month of the hindu calendar has 30 days. Each day is also called as Tithi.
But how duration of a day is decided ?
Moon orbits at a greater speed around Earth. Angle between Sun and Moon continues to increase from 0 degree to 360 degrees from new moon to next new moon. If we divide 360 degrees in 30 equal parts, each part will be of 12 degrees.
Time moon takes to cover these 12 degrees is considered as one day or Tithi.
Like if it travels 12 degress, Pratipada - First day , after 24 degrees, Dwitiya - second day and so on ...
Due to elliptical orbits of moon as well as earth, speed is different at different locations. Sometimes it takes more time to cover 12 degrees while at other times it takes less time. That is the reason duration of a single day or tithi varies in Hindu Calendar . It fluctuates between 20 to 27 hours. In gregorian calendar each day is fixed as 24 hours.
From New moon phase, 180 degree travel marks Full Moon and 360 degrees marks the next new moon phase.
This part is also the waxing phase of the moon and is known as shukla paksha.
This part is also waning phase of the moon also known as Krishna paksh.
Tithi in Shukla Paksha is prefixed with shuddha while Tithi in Krishna paksh is prefixed with Vadya.
Shudh Pratipada
Shudha Dwitiya
Shudha Ashtami and so on
Vadya Pratipada
Vadya Dwitiya
Vadya Ashtami and so on
Lets move ahead
Next month Vaishakh starts from 12th May
26th May Purnima
10th June is new moon day , Amavasyya
Start of another month, Jeshtha
In every month, Sun transits from one raashi to another .
Like in the month of Chaitra, from Meen rashi to Mesh, In Vaishakh , to Vrishabh rashi and in Jeshtha Mithun Rashi.
If this transition does not take place in a particular month, that month is considered as extra month or adhik maas for that year.
12 revolutions of moon mark the completion of 1 year in Hindu Calendar
First month of next year, Chaitra starts from this position again.
In year 2022, Chaitra starts on 2nd April, almost 11 days in advance than the previous year. This is because each month is only 29.5 days approximately.
Moving on, in the year 2023, Chaitra month starts on 22nd March, 22 days earlier than 2021.
If same sequence is followed, we may have to celebrate hole in monsoon or Diwali in Summer.
This is where extra month or adhik maas comes handy.
Lets us move on.
Vaishakh, jeshtha, aashadh
17th July is amavasya or new moon day and Sun is in Kark Rashi.
Moon completes one cycle on 17th August but Sun is still in Kark Rashi.
There is no transition of Sun to another Rashi during this period. This month is considered as Extra Month or Adhik Maas.
Adhik Shravan
Month after is considered as regular Shravan as per earlier sequence.
Now sun has transitioned to Sinha rashi from Kark Rashi
Other months follow the sequence as usual.
In 2024, gudhipadva will be on 9th April , somewhat closer to 2nd April in 2021.
Introduction of extra-month or Adhik Maas enables synchronization of Solar and Lunar cycles in Hindu Calendar.
If one considers the start of Chaitra Month from 2000 to 2010, Sun is always in Meen rashi.
Just like transition of sun through rashis, transition of Moon through Nakshatra is also worth exploring.
We will learn more about this in the next video.
Thank you.
Let us understand various events associated with Sun, Earth and moon with the help of a model.
During this journey around the Sun, it also rotates around its own axis. This axis is not straight but slightly tilted at an angle of 23.5 degrees like this. This tilt is the reason we have seasons on Earth.
Just like it's revolutions around the Sun, Earth also rotates in anti-clockwise direction around it-self. One complete rotation around itself takes 24 hours while one complete revolution around Sun is finished in 365 days or 1 year. Let's take help of this dial so that position of Earth can be referenced as it revolves.
There are numerous stars around our solar system. These were grouped by our ancestors for easier identification. Also know as constellations. There are many but 12 are most important. These constellations mark out the path that Sun appears to take throughout the year.
Mostly known to us as Zodiac signs. Circle is divided into 12 equal parts. One part per zodiac sign.
This outer ring has months marked on it as per Gregorian calendar. Useful while discussing Seasons.
And months as January, February, March, April, May….
Let's move Earth by hand in steps and study orientation of axis as it revolves around the Sun. Front view is better for this instead of top view
21st June is the longest day in Northern hemisphere. North pole is at its nearest point towards Sun on this day. Hence this part gets more sunlight. Longest day and shortest night.
Exactly opposite situation is there in the southern hemisphere. Longest night and shortest day .
It's also known as summer solstice.
22nd September
22nd December
On this day North Pole is farther from the Sun. Northern hemisphere receives less Sunlight.
Days are shorter and nights longer. It's also known as winter solstice. Exactly opposite situation is there in Southern hemisphere.
21 March
Sun rises southward every day starting 21st June till 21st December in Northern hemisphere. And starts rising northward again from 22nd December. These two periods are Popularly known as Uttarayan and Daxhinayan in India.
This small plastic bead is our Moon.
While the Moon revolves around the Earth, Moon and the Earth revolves around the Sun.
It takes approximately 27.3 days for Moon to complete one revolution around the Earth. But Earth is also moving constantly. Moon takes more time to reach the same spot. 29.5 days.
The Moon itself does not generate light; it is lit up by the Sun. As the Moon orbits the Earth, the portion of illuminated Moon that we see changes – giving rise to the phases of the Moon.
The Moon does not produce its own light. There is only one source of light in our solar system, and that is the Su. “moonlight” is actually just sunlight reflecting off of the Moon’s surface. The Sun’s light comes from one direction, and it always illuminates, or lights up, one half of the Moon – the side of the Moon that is facing the Sun. The other side of the Moon is dark.
On Earth, our view of the illuminated part of the Moon changes each night, depending on where the Moon is in its orbit, or path, around Earth. When we have a full view of the completely illuminated side of the Moon, that phase is known as a full moon.
In this video, I short recently on a full moon day, moon is seen rising in the east while sun sets in the west. But following the night of each full moon, as the Moon orbits around Earth, we start to see less of the Moon lit by the Sun. Eventually, the Moon reaches a point in its orbit when we don’t see any of the Moon illuminated. At that point, the far side of the Moon is facing the Sun. This phase is called a new moon. During the new moon, the side facing Earth is dark.
We have a “new Moon” when our Moon's orbit around Earth moves it between Earth and the Sun. From Earth, the Moon's surface looks dark because the illuminated side is facing away from Earth. As our Moon continues its orbit counterclockwise around Earth (viewed from above the north pole), more and more of the illuminated part of the Moon becomes visible to us, until it reaches the “full Moon” stage. A full Moon occurs when the Moon has moved in its orbit so that Earth is “between” the Moon and the Sun.
When the Sun and Moon are aligned on the same side of the Earth, the Moon is "new", and the side of the Moon facing Earth is not illuminated by the Sun.
A waxing moon is a moon that gets more sunlight on it as the days go by. It is after we experience a new moon up to a full moon. A waning moon is after the full moon and will remain waning until we again experience a new moon.
Eclipse is another event familiar to us.
A lunar eclipse occurs when the Moon moves into the Earth's shadow.
A solar eclipse occurs when a portion of the Earth is engulfed in a shadow cast by the Moon which fully or partially blocks sunlight. This occurs when the Sun, Moon and Earth are aligned. Such alignment coincides with a new moon
If the Moon were in a perfectly circular orbit, a little closer to the Earth, and in the same orbital plane, there would be total solar eclipses every new moon. However, since the Moon's orbit is tilted at more than 5 degrees to the Earth's orbit around the Sun, its shadow usually misses Earth. A solar eclipse can occur only when the Moon is close enough to the ecliptic plane during a new moon.
Due to tile in the orbital planes of Moon and Earth, eclipses do not occur every 15 days.
Lets use this small dial to help is identify various phases of moon as it revolves around the Earth.
Same side of the moon
As speed of rotation of moon around its own axis and time it takes for one revolution around Earth is same, we always see same side of the moon. Let us mark a red line here. It is always facing the earth.
Makar Sankranti
We celebrate Makar Sankrant every year around 14th or 15th Jan. On this day, Sun enters from Dhanu rashi to Makar Rashi. But what does enter a zodiac means. ?
Sun is stationary just like many constellations around us. When observed from Earth, Sun appears to be in particular constellation in the background. This keeps on changing as Earth revolves around the sun. When these imaginary boundaries are crossed, we refer to it as SUN entering a particular constellation/ or zodiac sign or Rashi.
Most of the hindu festivals are celebrated as per Lunar calendar but Makar Sankrati is based on the transition of SUN. This is why it normally comes around 14th or 15th Jan of Gregorian calendar.
In the next video, we will discuss about Hindu calendar which considers lunar as well as solar position while deciding months.
Thank you.
