[Music] good day everyone this segment is for grade 12 students who are studying physical science but of course everyone who is willing and interested to learn is welcome to join us today we will talk about one of the most interesting questions in science how were the elements formed the calcium in our bones are elements how were they formed the air that we breathe are made up of elements how were they made are you ready to answer these questions if yes then please make sure that you have a pen and paper with you so you can write all the things that you will learn from this episode i am teacher iman and i welcome you to the very first episode of sciencequella tv where you can learn science concepts in fun and easy way i have identified eight important concepts that will help you understand the topic more easily let's see how many of these concepts you already know answer the true or false questions with science and quella [Music] science quella are you ready yes teacher okay for our first question true or false elements are made up of subatomic particles called protons neutrons and electrons the correct answer is true yes it's true protons are positively charged particles electrons are negatively charged particles and neutrons have no charge it is important for you to know this if you want to understand how the elements are made because these are the ingredients in making an element if you want to know how to bake a cake you need to learn the ingredients first the same is true with learning about element formation you need to know what the ingredients are question number two true or false the identity of an element depends on how many neutrons it has the correct answer is false [Music] the identity of an element depends on how many protons it has an atom that has one proton is hydrogen no matter how many neutrons and electrons it has if you add another proton to an atom of hydrogen it will stop from being a hydrogen and it will become helium imagine if you have a friend who is very talkative and then one day he came to class and he was very quiet what do you usually say hey you're so quiet today that's not you now imagine you saw an atom of hydrogen on the road if that hydrogen has two protons what do you say hey you have two protons that's not you you're not hydrogen you are helium if you don't know how many protons an element has just look at their atomic number and it will tell you the number of protons of that element it is also possible for a proton to turn into a neutron and for a neutron to turn into a proton when this happens the identity of an element changes question number three true or false lithium is one of the elements formed during the big bang nucleosynthesis the correct answer is true the very first elements were made a few minutes after the big bang through the process called big bang nucleosynthesis most of what were formed were hydrogen and helium however a few lithium and beryllium are also made if you look at the periodic table of elements you will notice that the ones at the top are the elements that i mentioned hydrogen helium lithium and beryllium this is because these elements are lighter than the ones at the bottom they are lighter because they have less protons and neutrons in their nuclei question number four true or false nucleosynthesis combines nucleons protons and neutrons to form new elements the correct answer is true nucleosynthesis came from the words nucleo which means nucleus and synthesis which means creating something new by combining separate materials studying about the formation of new elements may sound overwhelming at first but it's actually very easy it's really just all about colliding ingredients and then combining them to form a new element question number five true or false the big bang is an explosion [Music] the correct answer is false contrary to popular belief the big bang is not an explosion the word explosion is misleading that is why we prefer to use the word expansion to refer to big bang according to the big bang theory the universe was extremely small even smaller than an atom it was also extremely dense and extremely hot but 13.8 billion years ago it began to expand and the formation of most light elements occurred just a few seconds after the big bang question number six the universe was colder 13.8 billion years ago [Music] and the answer is false the universe was very hot billions of years ago however it cooled down as it expanded this fact is important in our study of element formation it tells us that there was a time when the universe was hot enough to form elements and then it stopped because it cooled down question number seven true or false the higher the energy of the particles in an object are the higher the temperature of that object will be the correct answer is true temperature is a measure of the average kinetic energy of the particles in an object the higher the energy of these particles are the higher the temperature of the object will be you're right quella look at the two sets of molecules on the screen let's all imagine that these are water molecules the molecules of the one on the left has more energy they are moving faster the one on the right has less energy which of the two do you think is hotter if you think that the one on the left is hotter than you are correct if you are too shy to tell your friends that you are hot maybe you can tell them that the particles inside you have a lot of energy if they watch this they won't be confused with what you mean the temperature of the universe can also tell us whether or not it's possible for new elements to be created there when it's too hot the particles have too much energy they just get destroyed when they collide if the particles lack energy they will just bounce upon collision no new element made however if the temperature of the universe is just right protons and neutrons can combine when they collide when that happens new elements are made last question true or false mass can be converted into energy [Music] the correct answer is true we learned from the law of conservation of mass that mass can neither be created nor destroyed however einstein's theory of relativity e is equal to m c squared tells us that mass can be converted into energy it is important for us to understand and to know that it is possible for mass to be converted into energy later you will see that when elements are made energy is released now where does this energy come from it comes from mass [Music] so how did you do were you able to answer everything correctly if not then that's fine it only means that there's still a lot to learn and i know that you're very excited to learn about how the elements were formed so take it away professor atom thank you teacher eman did you know that protons and neutrons formed a few seconds after the big bang at first the universe was so hot and the particles were so energetic that when they collided they just got destroyed however the universe is expanding and as the universe expands it cools for a few minutes after the big bang the temperature of the universe reached the point where the protons and neutrons could combine when they collided through this process new elements were made and we call this the big bang nucleosynthesis how does this big bang nucleosynthesis work protons and neutrons collide and combine to form to tiron deuteron is an isotope of hydrogen that has one proton and one neutron how do we know that this deuteron is an isotope of hydrogen and not of any other elements it's because it has one proton and all atoms that have one proton is hydrogen soon another neutron collides and combines with it to form triton again this is an isotope of hydrogen because it has one proton then again another proton collides and combines with it to form helium we know that this is helium because it has two protons most of what were formed were hydrogen and helium however some lithium and beryllium were also formed one way lithium was formed was through the collision and combination of helium-4 and triton and one way beryllium was formed was through the collision and combination of helium-4 and helium-3 as the universe continued to expand the temperature dropped to a point where the particles no longer had enough energy to combine when they collide they just bounced the universe was able to create a lot of hydrogen and helium and a few lithium and beryllium that is the process of big bang nucleosynthesis as you can see it is very straightforward and very easy to understand all you have to remember are the words collision and combination now that we know how the light elements were formed the question that remains is how are the elements heavier than beryllium formed so far we've learned that we need enough heat so that the particles have enough energy to combine when they collide however we know that the universe can no longer provide that heat because like what we learned earlier as the universe expands it cools now can you think of a hot place where heavier elements could possibly form if you thought of the sun then you are correct yes some heavier elements were formed in celestial bodies like the sun the stars and that made me think of the nursery rhyme twinkle twinkle little star and i'd like to share to you the senior high school version of that song twinkle twinkle big big star now i know how hot you are heavy elements exist because of you gold calcium oxygen and silver too so what have we learned from this song that i hope you sang in your head the rhyme tells us that stars don't just twinkle they do more than that they make it possible for elements to form it also tells us that stars are not little they're big and they only look small because they're very far away lastly the rhyme tells us that stars are so hot they can provide energy for another type of nucleosynthesis the stellar nucleosynthesis when elements are formed inside a star we call that stellar nucleosynthesis it all starts with a stellar nebula the stellar nebula is the birthplace of the star it is called such because it is where the stars are born it is a huge clump of gas and dust particles eventually gravity will collapse this structure and as it collapses the force of gravity increases the kinetic energy of the particles hydrogen atoms gain enough energy to collide and combine to form helium atoms through the process called nuclear fusion in a nutshell nuclear fusion happens when atoms gain enough energy to combine when they collide this process releases huge amount of energy have you ever wondered why the sun is so hot where does it get its energy from it gets its energy from nuclear fusion when four hydrogen atoms combine to form helium some of the mass of hydrogen is converted into huge amount of energy this energy blows the contents of the star out but instead of being ejected the contents of the star are held in place by gravity when the star is at this stage we say that it is in its main sequence stage currently the sun is at this stage now what happens inside the star in its main sequence stage depends on how big it is in other words different types of nuclear fusion happens inside the star depending on how big it is for medium-sized stars like our sun the proton-proton chain reaction is dominant for more massive stars the cno or carbon nitrogen oxygen cycle is more dominant the proton proton chain reaction starts with two protons or two hydrogen atoms colliding and combining as they combine one of the protons turns into a neutron because of this a positron and a neutrino are released the positron will annihilate with an electron and release energy we talked about this earlier it was mentioned that protons can turn into a neutron and neutron can turn into a proton now what we have left is a deuteron which is an isotope of hydrogen later another proton hits deuteron and helium-3 is formed when this helium-3 emits another helium-3 which was formed from the collision and combination of other hydrogen atoms they collide and they combine two protons will be released to perform another nuclear reaction and that is how helium is formed through the process of proton proton chain reaction back to you teacher iman that is how the light elements were formed during the big bang nucleosynthesis and how some light elements were formed during the stellar nucleosynthesis let's have a little review and see how much you learned about element formation [Music] at the beginning we reviewed eight important concepts that will help us understand how elements were formed these are number one all atoms are made up of subatomic particles called protons neutrons and electrons number two the identity of an element depends on how many protons it has just look at the total number of protons that an atom has and you will know what type of element it is number three the light elements hydrogen helium lithium and beryllium were the very first atoms to form number four nucleosynthesis combines nucleons to form new elements to form a new element all you really have to do is to collide particles and combine them number five big bang is not an explosion it is the expansion of space number six as the universe expands it cools this tells us that the universe was hot before hot enough to energize particles to combine and collide but as the time went by it became cooler and cooler number seven the higher the energy of the particles in an object are the higher the temperature of that object will be number eight mass can be converted into energy we also learned that a few moments after the big bang protons and neutrons were formed for a few minutes the universe was hot enough to make the combination of these subatomic particles possible and because of that helium lithium and some beryllium were formed however when the universe was no longer hot enough the nucleosynthesis stopped the story of the elements did not end there though stars were born and nuclear fusion occurred at their core inside hydrogen atoms combine to form helium and release energy now it's time to show how much you have learned please choose the letter of the best answer let's start with an easy one question number one which of the following is not considered as light element a helium b hydrogen c lithium or d iron [Music] the answer is d iron question number two which of the following is true about nucleosynthesis a it is the division of atomic particle b the combination of elements to form compound c it is the creation of everything including all matter in universe d it is the process of creating new atomic nuclei from pre-existing nuclei [Music] the answer is d it is the process of creating new atomic nuclei from pre-existing nuclei question number three at which phase of star life cycle is our sun in a main sequence star b planetary nebula c red giant or d white dwarf the answer is a main sequence star question number four how is the energy of the star produced a by combustion b by decomposition c by nuclear fission or d by nuclear fusion the answer is d nuclear fusion last question which type of nuclear fusion occurs at the core of a medium-sized star a alpha leather process b cno cycle c proton proton chain reaction or d tri-alpha process the correct answer is c proton proton chain reaction before we end this episode i'd like to share something that i hope will encourage you in this new learning setup many people may express doubt in your ability to learn without a teacher teaching you face to face remember you can choose to be like the moon that always depends on others to shine but you can also choose to be a star that shines whether or not there is light around congratulations you have reached the end of the very first episode of sciencequella tv on our next topic we will talk about how the heavier elements were formed inside the stars don't forget to come back next week for another episode because learning science with teacher iman is fun [Music] you