00:00light sound and force what will we learn we will learn about the following concepts in this lesson
00:17light shadow sound force let's get started neha and tushar did you clean your room after playing
00:30no mommy mommy we will clean it after coming back from the park
00:40no my dear you should always put the things at their right places after using them so now go
00:48and clean your room then both of you can go to the back okay mommy i cannot see anything neha can you
00:58see anything no tushar i am not able to see anything but while playing we were able to see
01:07everything yes exactly let's ask mommy about it she will help us mommy we went to our room
01:17and we could not see anything but earlier we were able to see everything that was present in the room
01:25why is it so mommy kids you are able to see everything because there was light in your room
01:34we need light to see things mommy what is light light is a form of energy the main source of light on the
01:48earth is the sun other sources like torch bulb candle lamp and stars also give us light
02:00these objects are called luminous objects mommy both sun and candle give us light are they the same
02:12no they both are different the sun is a natural source of light while candle is a man-made source of light
02:21light mommy are all objects luminous no my dear objects like tree chair table glass and pencil
02:35do not give us light and are called non-luminous objects we can see non-luminous objects only when
02:44light falls on them it means we can see things only when there is a source of light
02:53yes tushar you are right come we will go and see which source of light is present in your room
03:03so can you name the source of light present in this room
03:06yes mommy it is a bug very good neha tushar can you name another source of light present in this room
03:20mommy can we consider the window as a source of light
03:27no my child window is not a source of light the source of light is the sun
03:33the window helps the light of the sun to enter the room
03:41now i get it mommy that's very nice well there are a lot of things scattered around
03:49you both should clean all this now
03:53okay mommy look mommy there's something black on the ground near the chair
03:59oh that is the shadow of the teddy bear which you have placed on the chair
04:07oh but mommy what is a shadow
04:12when a source of light is blocked by an object a dark patch is formed on the opposite side of the
04:19source of light this dark patch is called a shadow you must have observed your shadow on the floor
04:28or ground when you stand outside in the sun it happens because the path of light coming from the sun
04:37is blocked by you mommy how does light travel light always travels in a straight line for example
04:50the light coming from the sun a torch and the headlight of a car travel in a straight line
04:59mommy can a shadow be colorful
05:04no my dear the shadow formed is always black or dark irrespective of the color of the object
05:11a shadow cannot be formed in the absence of a light source a shadow appears to be black
05:26black or dark irrespective of the color of the object it is always formed on the side opposite to the source of light
05:37it may be bigger or smaller than the object
05:40wow that's so amazing mummy mummy what is that it is very loud
05:49yes it is very disturbing as well it's the sound of a dog barking
05:59we all have heard the sounds like chirping of birds barking of dogs ringing of doorbells and crying of a baby
06:11all these sounds are very familiar we also make sounds when we speak or laugh
06:21sound is a form of energy produced by both living and non-living things
06:28different things produce different sounds
06:30yes just like the dog is barking loudly as compared to the chirping of birds
06:41they are so different
06:44both of you are right some sounds are loud while others are soft some sounds like music are pleasant
06:55while others like honking of a vehicle are unpleasant and disturbing this loud and unpleasant sound is called noise
07:07too much noise is disturbing we should always speak softly with everyone we should not play music system
07:17and television on a high volume it can disturb our family members and neighbors
07:26oh we will not play music system and television on a high volume
07:34yes mummy and i will also tell my friends not to make noise and disturb others
07:43that's very nice children children now start picking up all these toys and put them in the box
07:51this box
07:51this box is so heavy i am not able to move it
07:58don't worry let me try
08:00oh even i cannot move it oh my dear the box is too heavy you both need to apply more force to move it
08:13mommy what is force force is a push or a pull we need to apply force to do work
08:24we pull or push a door to open and close it similarly we push the pedals to ride a bicycle
08:35in all these cases we can see that an object is either pushed or pulled by applying force on it
08:44what all can we do by applying force we can do various things by applying force
08:54force we apply force to move an object we apply force to stop or slow down a moving object
09:04we apply force to change the shape or size of an object
09:10oh that means when we stretch a rubber band we are applying force on it
09:17that's right neha tushar can you give another example of applying force
09:23yes of course mommy we apply force when we catch a moving ball
09:31well done tushar you gave a brilliant example
09:35do you know the force that slows down or stops a moving object is called friction
09:40wow it means there are different types of forces mommy please tell us more about friction
09:50of course my dear when two surfaces come in contact with each other friction develops
09:59for example when our feet and the road come in contact with each other while walking
10:05friction develops between them and helps us to walk we would keep slipping on the floor without friction
10:16things slide when friction is very less things do not move when the friction is more
10:24but mommy how do we push this box to the corner yes mommy we are not able to move it
10:32that's easy why don't you both try to push it together maybe that way you can move it
10:44well done see when we work together we can achieve anything
10:50now you both can go and play outside with your friends
10:54thank you mommy for telling us so many wonderful things about light shadow sound noise force and
11:07friction we will share this information with our friends it was fun learning all this thank you
11:16what have we learned light helps us to see things around us
11:21examples of some luminous objects are sun star torch and lamp examples of some non-luminous objects are
11:30table chair and glass light always travels in a straight line a shadow always appears to be black
11:38or dark some sounds are pleasant while some are unpleasant we apply force to move an object
11:45stop or slow it down or change its shape or size friction helps us to walk children hope you enjoyed
11:54learning the concepts we will meet soon to learn new things
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