The atmosphere of Earth is the layer of gases, commonly known as air, that surrounds the planet Earth and is retained by Earth's gravity. The atmosphere of Earth protects life on Earth by creating pressure allowing for liquid water to exist on the Earth's surface, absorbing ultraviolet solar radiation, warming the surface through heat retention (greenhouse effect), and reducing temperature extremes between day and night.

By volume, dry air contains 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% carbon dioxide, and small amounts of other gases. Air also contains a variable amount of water vapor, on average around 1% at sea level, and 0.4% over the entire atmosphere. Air composition, temperature, and atmospheric pressure vary with altitude, and air suitable for use in photosynthesis by terrestrial plants and breathing of terrestrial animals is found only in Earth's troposphere and in artificial atmospheres.

The atmosphere has a mass of about 5.15×1018 kg, three quarters of which is within about 11 km (6.8 mi; 36,000 ft) of the surface. The atmosphere becomes thinner and thinner with increasing altitude, with no definite boundary between the atmosphere and outer space. The Kármán line, at 100 km (62 mi), or 1.57% of Earth's radius, is often used as the border between the atmosphere and outer space. Atmospheric effects become noticeable during atmospheric reentry of spacecraft at an altitude of around 120 km (75 mi). Several layers can be distinguished in the atmosphere, based on characteristics such as temperature and composition.

The study of Earth's atmosphere and its processes is called atmospheric science (aerology).

The three major constituents of Earth's atmosphere are nitrogen, oxygen, and argon. Water vapor accounts for roughly 0.25% of the atmosphere by mass. The concentration of water vapor (a greenhouse gas) varies significantly from around 10 ppm by volume in the coldest portions of the atmosphere to as much as 5% by volume in hot, humid air masses, and concentrations of other atmospheric gases are typically quoted in terms of dry air (without water vapor). The remaining gases are often referred to as trace gases, among which are the greenhouse gases, principally carbon dioxide, methane, nitrous oxide, and ozone. Besides argon, already mentioned, other noble gases, neon, helium, krypton, and xenon are also present. Filtered air includes trace amounts of many other chemical compounds. Many substances of natural origin may be present in locally and seasonally variable small amounts as aerosols in an unfiltered air sample, including dust of mineral and organic composition, pollen and spores, sea spray, and volcanic ash. Various industrial pollutants also may be present as gases or aerosols, such as chlorine (elemental or in compounds), fluorine compounds and elemental mercury vapor. Sulfur compounds such as hydrogen sulfide and sulfur dioxide (SO2) may be derived from natural sources or from industrial air pollution.

The nitrogen cycle is the biogeochemical cycle by which nitrogen is converted into multiple chemical forms as it circulates among atmosphere, terrestrial, and marine ecosystems. The conversion of nitrogen can be carried out through both biological and physical processes.

This live-action video program is about the term nitrogen cycle. The program is designed to reinforce and support a student's comprehension and retention of the term nitrogen cycle through use of video footage, photographs, diagrams and colorful, animated graphics and labels.

Viewers will see and hear nitrogen cycle used in a variety of contexts providing students with a model for how to appropriately use the term. Related words are also used and reinforced with visuals and text.

Important processes in the nitrogen cycle include fixation, ammonification, nitrification, and denitrification. The majority of Earth's atmosphere (78%) is atmosphere nitrogen, making it the largest source of nitrogen. However, atmospheric nitrogen has limited availability for biological use, leading to a scarcity of usable nitrogen in many types of ecosystems.

The nitrogen cycle is of particular interest to ecologists because nitrogen availability can affect the rate of key ecosystem processes, including primary production and decomposition. Human activities such as fossil fuel combustion, use of artificial nitrogen fertilizers, and release of nitrogen in wastewater have dramatically altered the global nitrogen cycle. Human modification of global nitrogen cycle can negatively affect the natural environment system and also human health.

Nitrogen is present in the environment in a wide variety of chemical forms including organic nitrogen, ammonium (NH+
4), nitrite (NO−
2), nitrate (NO−
3), nitrous oxide (N2O), nitric oxide (NO) or inorganic nitrogen gas (N2). Organic nitrogen may be in the form of a living organism, humus or in the intermediate products of organic matter decomposition. The processes in the nitrogen cycle is to transform nitrogen from one form to another. Many of those processes are carried out by microbes, either in their effort to harvest energy or to accumulate nitrogen in a form needed for their growth. For example, the nitrogenous wastes in animal urine are broken down by nitrifying bacteria in the soil to be used by plants. The diagram alongside shows how these processes fit together to form the nitrogen cycle.

Nitrogen fixation
The conversion of nitrogen gas (N2) into nitrates and nitrites through atmospheric, industrial and biological processes is called nitrogen fixation. Atmospheric nitrogen must be processed, or "fixed", into a usable form to be taken up by plants. Between 5 and 10 billion kg per year are fixed by lightning strikes, but most fixation is done by free-living or symbiotic bacteria known as diazotrophs. These bacteria have the nitrogenase enzyme that combines gaseous nitrogen with hydrogen to produce ammonia, which is converted by the bacteria into other organic compounds. Most biological nitrogen fixation occurs by the activity of Mo-nitrogenase, found in a wide variety of bacteria and some Archaea. Mo-nitrogenase is a complex two-component enzyme that has multiple metal-containing prosthetic groups. An example of free-living bacteria is Azotobacter. Symbiotic nitrogen-fixing bacteria such as Rhizobium usually live in the root nodules of legumes (such as peas, alfalfa, and locust trees). Here they form a mutualistic relationship with the plant, producing ammonia in exchange for carbohydrates. Because of this relationship, legumes will often increase the nitrogen content of nitrogen-poor soils. A few non-legumes can also form such symbioses. Today, about 30% of the total fixed nitrogen is produced industrially using the Haber-Bosch process, which uses high temperatures and pressures to convert nitrogen gas and a hydrogen source (natural gas or petroleum) into ammonia.

Discover hundreds of never-before-seen resources! Create your free account at https://my.happylearning.tv/ and start learning in the most entertaining way.

Educational video for children to learn about natural phenomena and disasters. They will also learn how some of the most common natural disasters originate and how they affect us, such as: drought, earthquakes, avalanches, storms, tsunamis, heat waves, landslides, volcanic eruptions, volcanoes, hurricanes, tornadoes and wildfires.

This video is a great natural science resource for elementary education.

Thanks for visiting us! If you want your children to smile and learn, subscribe! :D

If you like our videos, download Smile and Learn now. You’ll discover thousands of activities for children aged 3 to 12 yeards, all designed by educators. We have hundreds of games, interactive stories and videos in five languages: English, Spanish, Portuguese, Italian, Turkish and French. Try a month for free and start the adventure!

www.smileandlearn.com

Educational video for children in which they will learn what the Sustainable Development Goals (SDG) are. The Sustainable Development Goals are a list of 17 global goals adopted by the United Nations and the countries that make it up. They aim to eradicate poverty, protect the planet and ensure prosperity for all. Each goal has specific targets to be achieved by 2030. They are: ending poverty, zero hunger, good health and well-being, quality education, gender equality, clean water and sanitation, affordable and clean energy, decent work and economic growth; industry, innovation and infrastructure; reduced inequalities, sustainable cities and communities; responsible production and consumption, climate action, life below water, life on land; and peace, justice and strong institutions as well as partnerships to achieve these goals.

This video is a very useful and interesting resource for children. It is perfect for teaching what the Sustainable Development Goals are. It is an excellent video for primary education.
#sdg thanks for visiting us! If you want your children to smile and learn, subscribe! :D

If you like our videos, download Smile and Learn now. You’ll discover thousands of activities for children aged 3 to 12 years, all designed by educators. We have hundreds of games, interactive stories and videos in five languages: English, Spanish, Portuguese, Italian, Turkish and French. Try a month for free and start the adventure!

www.smileandlearn.com

Educational video for children that teaches how to subtract and add angles. To measure angles we use the sexagesimal system, which uses degrees, minutes and seconds as units. One degree equals 60 minutes, and one minute equals 60 seconds. The first step is to arrange the measurements of the angles you want to add, one below the other. You have to be very careful when positioning them so that they match exactly. In other words, the degrees go under the degrees, the minutes go under the minutes and the seconds go under the seconds. Once we have the angles correctly placed, we have to add each column separately. We start by adding the seconds, then the minutes and finally the degrees. It is important that the results of the seconds and minutes columns have a value between 0 and 59. If the minutes or seconds go over 59, we have to subtract 60 minutes or seconds and add one unit to the left. To subtract angles the first step is to place the measurements of the angles in the standard subtraction format, the smaller angle under the larger angle. To find out which is greater, look at the degrees. The figure with the largest number of degrees is the larger angle. If the degrees are equal, look at the minutes. The one with the larger amount of minutes should go on top. If the minutes are also equal, look at the seconds. Now you have to place the degrees under the degrees, the minutes under the minutes and the seconds under the seconds. Once you have placed them properly, first subtract the seconds, then the minutes and finally the degrees. It is important that the results of the seconds and minutes columns have a value between 0 and 59. If the top number of minutes is less than the bottom one, subtract one from the degrees, add 60 to the minutes, and continue with the subtraction.

This video is a very useful and interesting resource for children. It is perfect for teaching addition and subtraction of angles. It is an excellent video for primary education.

Thanks for visiting us! If you want your children to smile and learn, subscribe! :D

If you like our videos, download Smile and Learn now. You’ll discover thousands of activities for children aged 3 to 12 years, all designed by educators. We have hundreds of games, interactive stories and videos in five languages: English, Spanish, Portuguese, Italian, Turkish and French. Try a month for free and start the adventure!

www.smileandlearn.com

Educational video for children that talks about storms. A storm occurs when two air masses of different temperatures and pressures collide and cause phenomena such as rain, hail, snow, lightning, strong winds and even tornadoes! Storms can have different intensities, sometimes they are very mild and sometimes they are very destructive. There are many types of storms such as thunderstorms, sandstorms or snowstorms. Sometimes storms produce hail, which is balls of ice that fall from the sky. Hail can be very harmful to the agriculture, destroying crops and spoiling harvests. It can also cause damage in cities by breaking windows or denting cars.

This video is a very useful and interesting resource for children. It is perfect for teaching about storms. It is an excellent video for early childhood and primary education.

Thanks for visiting us! If you want your children to smile and learn, subscribe! :D

If you like our videos, download Smile and Learn now. You’ll discover thousands of activities for children aged 3 to 12 years, all designed by educators. We have hundreds of games, interactive stories and videos in five languages: English, Spanish, Portuguese, Italian, Turkish and French. Try a month for free and start the adventure!

www.smileandlearn.com

Educational video for children to learn about the thirteenth of the Sustainable Development Goals (SDGs), climate action. Climate is defined as the weather conditions that characterize a given place. This includes temperature, humidity and wind, among other things. Each year is hotter than the last and the levels of carbon dioxide and other harmful greenhouse gases continue to rise. For these and other reasons, the United Nations has made climate action one of its main sustainable development goals. Climate change is affecting all countries with no exceptions. Sea and ocean levels are rising and weather phenomena are becoming more extreme. We need to be aware of the climate change that our planet is undergoing, and we must try to minimize its effects as much as possible.

This video is a very useful and interesting resource for children. It is perfect for teaching what the Sustainable Development Goals are. It is an excellent video for primary education.

Thanks for visiting us! If you want your children to smile and learn, subscribe! :D

If you like our videos, download Smile and Learn now. You’ll discover thousands of activities for children aged 3 to 12 years, all designed by educators. We have hundreds of games, interactive stories and videos in five languages: English, Spanish, Portuguese, Italian, Turkish and French. Try a month for free and start the adventure!

www.smileandlearn.com

Educational video for children that introduces beach vocabulary words. We will talk about the words sea, sand, waves, sun, sunscreen, towel, sandcastle, bucket, shovel and swimsuit.This video is a very useful and interesting resource for children. It is perfect for teaching vocabulary related to the beach. It is an excellent video for primary and early childhood education.Thanks for visiting us! If you want your children to smile and learn, subscribe! :DIf you like our videos, download Smile and Learn now. You’ll discover thousands of activities for children aged 3 to 12 years, all designed by educators. We have hundreds of games, interactive stories and videos in five languages: English, Spanish, Portuguese, Italian, Turkish and French. Try a month for free and start the adventure!www.smileandlearn.com

Educational video for children that talks about some weather instruments. Nowadays, meteorologists, the scientists who study atmospheric phenomena, use weather instruments to observe atmospheric weather patterns. By studying and measuring patterns such as precipitation, humidity, atmospheric pressure, temperature or wind, meteorologists can get an idea of what the weather will be like in the future. One of the instruments that helps them do that is the weather vane, which is put in high places, such as on the roofs of houses, and helps us to know the wind direction. The anemometer is a weather instrument that measures the speed or strength of the wind over a period of time.

This video is a very useful and interesting resource for children. It is perfect for teaching about weather instruments. It is an excellent video for elementary education.

Thanks for visiting us! If you want your children to smile and learn, subscribe! :D

If you like our videos, download Smile and Learn now. You’ll discover thousands of activities for children aged 3 to 12 years, all designed by educators. We have hundreds of games, interactive stories and videos in five languages: English, Spanish, Portuguese, Italian, Turkish and French. Try a month for free and start the adventure!

www.smileandlearn.com

In this submarines for kids video, toddlers will learn about underwater vehicles with Speedie DiDi! This is a fantastic toddler learning video, where Speedie DiDi shows children various water vessels including: real submarines, submarine toys, ships, boats, special underwater submarines as well as a short submarine cartoon. There are different kids learning videos included, these clips allow children to obtain an in-depth understanding of how a submarine works, the large size of the vessel, various rooms inside, as well as torpedoes! This educational video would be interesting to boys and girls of various ages including 2 years old, 3 years old and 4 years old (as well as much older kids!). The video starts with several submarines in the water, it then proceeds to show Speedie DiDi inside a real submarine and holding a submarine toy to introduce the concept to children. Speedie DiDi then helps toddlers learn about the water vehicles by showing them toy submarines of different sizes, a short submarine cartoon and real giant military submarines. Speedie DiDi also helps toddlers learn about torpedoes and shows them how they are launched and how they reach a ship. In addition, this educational video breaks down the many different rooms inside a submarine including: engine room, control room, torpedo room, etc. There are a lot of interesting water vehicles featured in this video: ships for children, military vehicles, boats for kids, various underwater vehicles, and a ton more! This is a fun and educational video for kids of all ages includes toddlers, kindergarten and preschool children. Big THANK YOU to the Site historique maritime de la Pointe-au-Père for having us! If your children love submarines, it's a fantastic place to visit. If you’re looking for the best educational videos for toddlers, you will love watching Speedie DiDi. Our toddler learning videos are getting kids interested in some very advanced topics, because we teach kids in simple terms that are easy to understand. Thank you for watching! #speediedidi, #submarinesforkids, #kidslearningvideos, #toddlerlearningvideo, #submarinesfortoddlers

Discover hundreds of never-before-seen resources! Create your free account at https://my.happylearning.tv/ and start learning in the most entertaining way.

What are you waiting for? Looking after our water, rivers and seas.

Hello friends, I am the Earth, yes that’s right, the very planet you live on and today I woke up a bit sad. Do you know why? It is because I dreamt that there was even more water pollution, so much so that all living things that live in the sea, oceans and rivers had disappeared. Even though it was just a dream, I can assure you that if you don’t stop contaminating the water, bit by bit; this horrible dream will come true.

The water´s contamination worries me tremendously, especially when thinking that three quarters of my surface is water. Even though I am named “the Earth”, if you were to look at me from space, you see more water than land and that’s why I am also referred to as the blue planet.

Everyone knows that water is imperative for life, without water there would be no plants, nor animals, nor even us, human beings. Yet still many people continue to throw rubbish bags, bottles, furniture… into the ocean and rivers, as if they were a container where one can get rid of all the things one doesn’t want any more.
In many houses, liquids such as oils and dirty products are poured into the drains, and then these get mixed with water and this contaminated water then travels through pipes to the seas and rivers.
There are also factories which throw their chemical wastes into the waters making them extremely contaminated, killing loads of aquatic animals. Here you can see a seal eating a plastic bag thinking it is food…we don’t know if the poor thing will survive. Or this frog lying dead because of contamination.

Another of my surface waters´ enemies is petroleum. You have no idea the damage it has caused to my seas and oceans. The sinking of ships transporting this oil has caused tremendous catastrophes, which only heal with the passing of time.
But I don’t want to upset you with all that I have told you, as bad or complicated things may seem; there is always a solution. And, I am positive that if you were to help me, all together, working as a team, we will make the water clean again and all living things will be safe.
A way you can help is by collecting all your trash the day you go on an outing, and never ever throw it into the river or sea. Another way to help is by not throwing any oils or other liquids into the drains, such as paint for example.
We can all encourage our families and friends to improve their habits and start to think about the importance of ending our water´s contamination.

Looking after water is taking care of life, too.

This is why you have a great responsibility. I need each and everybody’s help to remain healthy. If you take care of the water, you will be taking care of me, my nature as well as all living things. I have no doubt that together we will make sure my sad dream will never come true.

For as you know…children make a world of difference.

Discover hundreds of never-before-seen resources! Create your free account at https://my.happylearning.tv/ and start learning in the most entertaining way.

What are you waiting for? Happy Learning is channel for kids. Here they can find educational videos with which they can learn and have fun.
We have two playlist, the first one is for toddlers and the second is for children a little bit older;
▶ PreSchool Playlist: http://bit.ly/Preschool-HL
▶ Educational Videos: http://bit.ly/EducationalVideos-HL

▶ SUBSCRIBE HAPPY LEARNING! http://bit.ly/HappyLearningTV

The Moon and the Earth

Hello friends, welcome to a new video from Happy Learning. Today we are going to learn about… the Moon.

The Moon is the only satellite that rotates around our planet and it takes 28 days to completely go around the Earth. But, do we now what a satellite is? A natural satellite is any kind of celestial body that rotates, or actually, orbits around a planet.

The Moon is never still, it moves and in two ways. It has a movement of rotation, which means it turns in its own axis, and a movement of translation, that is to say, it rotates around the Earth.
The duration of the movement of rotation and translation is 28 days. Because it takes the same amount to rotate on its own axis and to completely go around the Earth, the Moon always shows us the same face.

When we observe the Moon along a period of time it appears to change shape. These changes in appearance are called lunar phases and they repeat every 28 days. There are four: full Moon, first quarter, new Moon and last quarter. The Moon phases are produced by two reasons: the movement of the Moon around the Earth and because the Moon reflects light form the sun as a mirror.

New Moon
In this phase the Moon is passing between the Earth and the Sun. The illuminated face of the Moon is facing the opposite direction to Earth. The dark side ends up facing the Earth, and this is why we cannot see the Moon.

First Quarter
You can see it approximately one week after the new Moon. One half of the illuminated side faces the Earth. It is called the first quarter because, from the new Moon phase, the zone illuminated by the sun grows every time.

Full Moon
Approximately a week after the first quarter, we can see the whole Moon illuminated. The Earth is between the Moon and the sun and we can see it fully.

Last Quarter
The Moon presents its other half face illuminated. The name of the last quarter comes from the fact that the illuminated side becomes smaller and smaller each time

A very easy trick to now whether the Moon is in its first or last quarter is the following. If the Moon has the shape of a C, it is in its last quarter and if it has the shape of a D, it is in its first quarter.

So now you know, the Moon has 4 phases:
New Moon, first quarter, full Moon and last quarter.

Know we are going to learn a few facts about the Moon

Do you know the distance between the Moon and the Earth? Although it looks as though it is not very far away, the Moon is about 385,000 kilometers from the Earth.

Another very interesting fact is that a rocket takes three days to get to the Moon. Its incredible, isn’t it?

The first astronaut that stepped on the Moon was Neil Armstrong and this very important accomplishment occurred in the year 1969 aboard the Apollo 11 rocket.

The Moon is 4 times smaller than the Earth, but it is very important for the sustainability of life in our planet. The Moon generates tides; Do you now what that is? A tide is the rise and fall of the sea level. They occur every 6 hours approximately.

Well now you know a little bit more about the Moon, very interesting, right?

Bye friends and don’t forget to subscribe to the Happy learning channel.

Discover hundreds of never-before-seen resources! Create your free account at https://my.happylearning.tv/ and start learning in the most entertaining way.

What are you waiting for? ▶ SUBSCRIBE HAPPY LEARNING! http://bit.ly/HappyLearningTV
Educational Videos and songs for Kids. The solar system planets, mercury, venus, earth, mars, jupiter...

Today we’re going to learn about the Solar System. As you know, the Sun is a star, one of the many stars that form the Milky Way. But for us, it is the most important star shining in the sky.
Planets move around the Sun, and so do comets and asteroids. Well, the Sun and everything that revolves around it is what we call the Solar System.
The most interesting things that we should know about in the solar system are the Planets. Let’s look at them, starting with the ones closest to the sun, and then getting further away!
The closest planet to the Sun is Mercury... then there is Venus... then comes the Earth. Yes, our planet where we live... Then there is Mars... Jupiter, the largest planet... Saturn... Uranus... and then the furthest away is Neptune.

▶SUBSCRIBE TO HAPPY LEARNING! http://bit.ly/HappyLearningTV
"Educational Videos and songs for Kids"

As you can see, Mercury, Venus, Earth and Mars are closer to the sun and also smaller than Jupiter, Saturn, Uranus and Neptune.
One important thing you should know is that the journey that all planets make around the sun is called an orbit.
Now, a question: do you know where the days of the week... get their names from...? Well, if we think about it for a minute... the Moon, which is not actually a planet itself, but Earth’s natural satellite... gives it name to Monday... Tuesday, Wednesday, Thursday and Friday come from ancient British gods that were related to the planets Mars, Mercury, Jupiter and Venus... Saturday gets its name from Saturn.... and of course, the Sun itself gives us the name Sunday. So if you remember that there is also Uranus, Neptune and our own Earth, then you know all the names of the eight planets in the solar system.
Easy, eh?
So, goodbye for now, everyone. And don’t forget to subscribe to Happy Learning!

A fun and educational game for children to enjoy!

--------------------------------------------------------------------------

One4kids TV CHANNEL:

Watch all our videos without any ads on our online TV channel here: https://www.one4kids.tv/

Download Apple APP free: https://itunes.apple.com/us/ap....p/one4kids-tv/id1291
Download Android APP free: https://play.google.com/store/apps/details?id=com.one4kids&hl=en

By subscribing to our channels, you are supporting our work.

--------------------------------------------------------------------------

One4kids ONLINE STORE:

Buy Zaky & friends merchandise from our online store: https://www.one4kids.net/

--------------------------------------------------------------------------

One4kids SOCIAL MEDIA PAGES

For latest updates, follow us on our social media platforms:

Facebook: https://www.facebook.com/one4kids/
Instagram: https://www.instagram.com/one4kids_zaky/?hl=en
Twitter: https://twitter.com/One4kids_Zaky

Discover hundreds of never-before-seen resources! Create your free account at https://my.happylearning.tv/ and start learning in the most entertaining way.

What are you waiting for? Means of Transport, coche (car), bicicleta (bicycle), globo aerostatico (hot air balloon), camion (lorry), barco (boat), autobus (bus), avión (plane), tren (train), moto (motorbike), helicoptero (helicopter) means of transport. Happy learning

▶SUBSCRIBE TO HAPPY LEARNING! http://bit.ly/HappyLearningTV

⁣ނަން ބެހިގެންވާ ބައިތައް

Welcome aboard! Have fun knowing the different water transportation!
This video lesson includes words and a short description of each transport. Learn the following words: sailboat, fishing boat, speedboat, rowboat, canoe, water scooter, submarine, and cruise ship.

Background music
–––––––––––––––––––––––––––––––––––––––––––
Track: Quincas Moreira - Sand Castle
Music provided by No Copyright Music
Watch: https://www.youtube.com/watch?v=PAgBpRqTap8
–––––––––––––––––––––––––––––––––––––––––––
OnlineClass4Kids aims to produce videos with rich and interactive content.
Our channel is a perfect spot for a safe virtual environment for learners.
Our videos are crafted carefully by a team of experts.
We dream of enriching and teaching the minds of young ones by developing a channel where they can enjoy and broaden their knowledge.

For more educational materials, subscribe!
https://www.youtube.com/c/OnlineClass4Kids

Happy learning!

00:00 Introduction
00:36 What is Water Transportation?
01:05 sailboat
01:21 fishing boat
01:38 speed boat
01:52 rowboat
02:04 canoe
02:20 water scooter
02:37 submarine
02:52 cruise ship
03:11 Revision

Lets study about Modes of Transportation with this video.

For more videos go to:
https://www.youtube.com/user/l....earningjunction/vide

Stay tuned for more videos.

Thank you