Measurement and Units Explained | Class 6, 7, 8, 9 Science | Length, Mass & Time | Easy Learning

[00:00:00]topic is measurement, physical quantity and measurement.

[00:00:05]Please join with me because I exam this exam will start very soon. Please clear your all doubts. Okay, I'm waiting for 1 minute for all the kids then I will start.

[00:00:42]Look, can you tell me the length of the scale?

[00:00:46]Yes, it is 15 cm. Now if I throw away all the scales and tell you find out the uh measurement of the blackboard, how can you find out?

[00:01:03]Think and tell me some organs especially, hand, finger, foot, rope.

[00:01:26]We can use in the previous time when there is no ruler at that time no tape no ruler at that time how can they measure the measure everything. So this is hand finger foot and r now check it is called hand span.

[00:01:47]But if we check in this way suppose one by one student come and check the board and if someone's result is um eight hand spam someone's result is nine sam uh hand spam then question if the board size is same then why the answer is different is because is because um it is our body part and body part length are not same. So different person body part length different so hands can be different for that reason it's the measurement of the board not accurate not accurate approximate can find out clear so from the conclusion what we are telling Body part equal to not standard unit.

[00:03:20]Not standard unit. Clear? Please copy from the board. body part equal to non-standard unit.

[00:03:32]Okay.

[00:03:38]In the old time and ancient time the farmer measure the land by step also.

[00:03:47]And one more thing in the ancient time we also use the finger. The width of the finger we use just anguli.

[00:03:57]Angoli if it is one means one finger width is the measurement. If it is four anguli means four finger the width of the four finger is the our measurement.

[00:04:09]We check it by the approximate and measure. If you are thin person then your finger is thin and your result is different but approximate we can do this one. And another uh previous in the old time one and uh unit is the year. What is the year? If you touch your nose and span your left hand in this way from here to the thumb you span your left hand from nose to your thumb left and thumb the distance is called ear. Clear?

[00:04:46]Another two old units is Dhanush and Yojun. Yojen. Now Dhanush means suppose there is lots of arrow is there. So one length of the arrow we take it is a unit and suppose we can measure the uh room. So we we may measure the arrow and one length of the standard unit and then what is what we are doing we measure it is 10 unit it's called dhan next one jo means it is a big length unit suppose you can find out the distance between two cities in that case you can't tell cm you can't use meter.

[00:05:40]You can you can use kilometer but the previous time we can't use kilogram but kil kilometer at that time it is not present so we use that type but now it is not it is oxidate then what is You need what is unit? Unit is a standard quantity and through this we can measure different things. Suppose you I tell you what is the uh length of the pen. You tell ma'am it is uh seven.

[00:06:34]Your answer is right. No. Why? Because you can't use any unit.

[00:06:43]Okay. So if you write it is uh 10 cm 10 in then it is okay. Suppose it is 10 only 10. It is not without unit we can't express any quantities. We write 10 cm here. What's the deal? 10 is the number and cm is the unit. You please copy it from the board.

[00:07:20][cough] Please copy it from the board.

[00:07:50]Why unit is important for measurement?

[00:07:54]Why unit is important? Suppose you went to the market. Your brother also went to the market and you buy the rice. You tell the uh shopkeeper please give me five rice. You do not use any unit. Then shopkeeper how can a shopkeeper understand it is 5 g 5 kg 5 quint.

[00:08:19]So for that reason we use unit and through unit we can measure it everything properly.

[00:08:29]Uh to for that reason we can tell without unit we can't express any quantity.

[00:08:38]In the case suppose uh you go to the market you think this is this amount is uh 100 g I don't know this amount is not 100 g this amount is 100 g look two amount are different to for this the measurement is not okay for that reason in the world one measurement we take the standard means 1 kg Means this amount it is not only India it America, Australia, Gujarat, Rajasthan or any countries its amount is 1 kg means it is 1 kg and when I tell 10 kg by it means this is our standard unit 1 kg it's multiple 10 times so it is our answer clear so in the word to avoid the confusion We we fix a particular weight or length for the standard.

[00:09:51]Now uh I tell some physical quantities most normal physical quantity mass, weight, length, temperature, [clears throat] pressure.

[00:10:26]If there is any doubt, please write in the chat box. I will check the chat box.

[00:10:32]Please write any doubt.

[00:10:41]What is your doubt? Please write in the box.

[00:10:45]Axara, please write in the chat box.

[00:10:47]What is your doubt?

[00:10:59]Time also. Yes. Very good my dear. Time also.

[00:11:04]It is the normal physical quantity to whom we can measure. To how can we measure the time? We can measure the time by clock.

[00:11:26]my clock.

[00:11:30]How can I measure the mass?

[00:11:33]Mass is balance.

[00:11:41]Weight.

[00:11:43]Weight and mass are different things according the physics in generally what we are telling I am 60 kg weight no it is absolutely wrong I am my mass is 60 kg and when the mass is multiply by g gravitational it's become weight how can we measure spring balance Len, ruler, temperature, thermometer, pressure, barometer, Please copy from the board.

[00:12:56]Super my dear. Yes. Thermometer for the temperature. Okay. Very good. Very good.

[00:13:03]Aara. Very good my dear. Carry on.

[00:13:24]Please copy from the board.

[00:13:35]Okay. Now I tell one new thing unit.

[00:13:52]What is the unit? Unit is a standard quantity to measure any anything. Now I unit I unit is three times.

[00:14:11]CGS, FPS, MKS, CGS, FPS, MKS unit is only three times.

[00:14:35]CDS cm, gram and second. It is a small unit.

[00:14:40][music] When we measure any small things, we can use this units foot pounder and second.

[00:14:50]Next one MKS [cough] [clears throat] meter, kilogram and second when we use more means uh meter, kilogram, it is a little bit big unit.

[00:15:05]Clear? But it's starting from one thing everything. Now I tell what is the CGS and what is the relationship between CGS 1 m equal to 100 cm.

[00:15:35]Check it properly.

[00:15:37]Suppose this is one m. This is 1 m.

[00:15:48]What we are doing?

[00:15:51]We break the 1 m small small 100 part.

[00:15:57]Okay. I start from I'm not doing full. I just do In this I break the 1 m into small 100 part in one part is called 1 cm. Clear? So what is the relationship? 1 m equal to 100 cm.

[00:16:21]Is it clear? Please copy it from the board. Cm and meter both we can use to measurement the length. Kilometer also used to measurement length. Suppose um I tell you find out the um distance between two uh two towers. How can you do cm you use? No. So at that time you think cm we use only small. Suppose I tell it is find out the length of the cap. Yes. In that cases you use cm but when it is more then we use meter and after that we use kilometer. Clear? Like a same thing kilogram. Gram is small unit as a 1 g of sugar. You need 1 g of sugar to prepare the juice. So at that time you need only small amount of sugar. At that time you use only gram.

[00:17:26]But when I tell you no uh for the cooking full month we need five uh kg sugar to 5 kg and grams both are related same. One is small unit one is but where we use according our necessity we use a small unit and we use the big unit.

[00:17:53]Is there any doubt?

[00:18:11]Aara, please write on the chat box which part I should repeat. This one.

[00:18:18]This part. Okay, I repeat one more time.

[00:18:22]It is the relationship between two units. What I'm telling length we can't use different type of unit like as kilometer big unit meter medium unit cm small unit.

[00:18:58]Clear?

[00:19:00]But all the three units are interrelated.

[00:19:05]All the three units are interrelated. I start from the meter. Suppose this to this is 1 m.

[00:19:16]What is the relationship between me and cm?

[00:19:28]1 m is 100 cm means they is 1 m. Okay. But what is the if I converted meter into cm? How can I do?

[00:19:47]This is 1 m. I break the 1 m 100 small small piece. Look, I divide it.

[00:20:00]I divide it by the blue lines. It is not 100 is possible. I just do this one.

[00:20:07]Okay. This one lines, two lines between length is called 1 cm. Cm also a unit which we use for the measurement of the length but it is a small unit and what is the relationship between cm and meter 1 m equal to 100 cm. Now 100 cm if you break 1 cm small small then it is it is one more smallest unit it is millm.

[00:20:45]Okay, clear. 1 cm equal to 10 mm. Clear.

[00:20:51]And then m 2 kilome we can convert 1 is big 1 kilometer in bracket small small for 1,000. The 1 kilome equal to 1,000 m. It is called the relationship by abbreviation between the two units.

[00:21:08]Clear?

[00:21:39]Scent means means 1 by 100 part yes what I'm telling 1 m I divide 1 m into 100 small part and one small part is called cm it's called ci [clears throat] means one by 100 why 100 is because previously what I'm doing I divide 1 m into equal 100 part. So I divide it 100.

[00:22:16]If I divide 1 m into equal 1,000 part then it is 1 by,000. Clear?

[00:22:24]No.

[00:22:32][clears throat] Now I draw a line and measure it.

[00:22:50]I draw a line.

[00:22:58]Look it is 15 cm.

[00:23:03]Question why I do this one? Suppose in the exam it is coming you draw a lines but your teacher told find out the length of the scale by anything. Find out the length of this one and at that time how can you check it?

[00:23:21]suppose is the L and you when you check your eye perpendicular to the ruler how it is possible suppose it is the scale now I stand here and I check it in that time my eye not measure properly it's come the result come 15.2 2 cm.

[00:23:48]Clear? Now I stand this side and check the ruler. My eye is in this way slanting way. My slanting way. But it's not accurate result is come 14.8 cm.

[00:24:06]Okay. Both are wrong. How can I do? I just put the scale straight. My eye is just this line 90° perpendicular. Okay. My eye is perpendicular to the scale. Then your measurement is okay. Clear? What I am telling? When you measure anything, your eye always perpendicular to that point.

[00:24:42]If your eye is not perpendicular, it is uh left side or right side slanting, then the error will become.

[00:24:54]If any doubt, please add in the chat box.

[00:25:46]Another big unit of the length is light year.

[00:25:55]Light year.

[00:25:59]What is the meaning of the light year?

[00:26:04]You can understand from the name light means it obviously related with the light and it's another way it is also related with the year.

[00:26:16]Then questions where we use this big unit in generally when we find the distance between sun and earth and moon big big in that cases kilometers me cm is not possible we use a big unit and this big unit is light year now I tell what is the light year light what's the light speed the Speed of the light is 3 into 10 ^ 5 kilome/ second. Means in 1 second light can cover this distance 3 into 10 ^ 5 kilometer in 1 second. If light goes all through the year the same speed means versus 1 second speed 320^ 5 kilome per hour. This speed it continue 1 hours no break no nothing nothing no rest anything then after 1 hour 1 years what is the distance a huge distance is come this distance is called one light year clear questions how the questions will become in the exam number one questions light year where we use lightear unit use used for which uh which type of measurement we use light. Length, mass, cell and temperature obviously length where we can use light year in general big distance to stars distance, sun, moon distance in that cases we use light year. And next is uh what is the definition of liar?

[00:28:31]10 to the power five. I clearly wait 100 how can I write our base is two power is two 10 is base and power is two 10 into 10 it's come 100 in all cases base is 10. Next 10 the power 3. It means 1 how many zero is there? Three zeros.

[00:29:13]Come clear. 10 to the power five.

[00:29:18]10 to the power 5 means our normal base is 10 and power is it is called power. It's called base. When you will go to the class 8 you can do the math exponent and it is a one type of exponent. So you just learn only that part 10 to the power five means 1 and 5 0 clear now only this part is okay for you I'm not explaining more part it is an exponent part when we will go to class 8 at that time I clear the exponent.

[00:29:56]have any questions?

[00:30:01]If it is clear, please write in the chat box. Ma'am, it is clear.

[00:30:10][laughter] There is a coin.

[00:30:23]One coin.

[00:30:25]Two coin.

[00:30:27]Three coins.

[00:30:30]Four.

[00:30:32]Five.

[00:30:34]Six.

[00:30:36]7.

[00:30:37]8.

[00:30:39]9.

[00:30:41]10. 10. Coin.

[00:30:45]10 coin. I tell find out the length of the bar. Find out the thick of a coin.

[00:30:53]You know what is called the thickness.

[00:30:55]Just wait one minute.

[00:31:21]Look it is five rupees coin. What is the thickness? Thickness means this these things is called this length is called thickness. Okay. Suppose this is a book.

[00:31:35]This is the book. The thickness of the book is this. This is called thickness.

[00:31:43]So now what's the question? There is 10 coin one by one by one by 10 coin you put on the on the table. Now question is how can you find out the thickness?

[00:31:58]How you how can you find out the thickness? Just like I check it.

[00:32:05]Suppose it is suppose 20 cm.

[00:32:23]Total th total thickness 20 cm. How can I measure? I put one by one by coin and through the scale I can measure it. Clear? I can measure through the scale. But what is the question?

[00:32:46]Question is what is the thickness of the one coin? It is 20 coin 10 coin. So one coin thickness total thickness total length 20 by number total length by number of the coin. Number of the coin 10 10 cm cancel it is 2 cm.

[00:33:20]Clear? And it is most important in the exam they are giving in this way. I tell I give a mass you please find out the answer. If there is any doubt how can you do one by one by coin you put you find out the length of the total coins.

[00:33:40]Suppose it is the result is 20 cm. Now the total length is formula is total length by number of coin.

[00:34:02]It is a formula total length by number of now I give a math. You try and write the answer in the chat box. Just 2 minutes.

[00:34:16]>> [laughter] >> The thickness of 15 coins. lines is 45 cm.

[00:35:24]What is the What is the thickness of one coin.

[00:35:40]I give you five minutes time. Please complete the math and write in the chat box.

[00:35:57]Super very good. Total 45 divided by 15 it is 3 cm.

[00:36:08]Please give a start on the questions.

[00:36:11]It's most times it will become in the exam. Okay. Now go to the next point.

[00:36:19][laughter] Good job.

[00:37:23]Suppose I want to find out the diameter of this R. So how can I do?

[00:37:31]I just in this way coil.

[00:37:40]Okay.

[00:37:42]Now what I am doing? I measure this part. Suppose this part is uh 8 cm.

[00:37:52]Then what is our now you count how many coils is there? How many total ring is there? You find out this thing.

[00:38:13]Length of the coil.

[00:38:17]Length of coil eight.

[00:38:23]I give all the example as a numerical example. But in sometimes it will give the X Y Z. Why they use X Y Z? Because we can take. So we can use XY Z this variable also.

[00:38:41]After that what we are doing length of the coil means length means what we are measur measure but this is all. Now number of the ring but number of the coil number of coil suppose it is number of the coil it is 40 mean how many times you ring on the pencils on on the I do it on the pen it is 40. So the thickness same 8 by 40.

[00:39:22]8 by 40 means 1 by 5. 1 by 5 cm.

[00:39:31]Otherwise you can change it to the decimal also. No problem. It is uh.20.

[00:39:38]It is also no problem. You can take as write the answer 1 by five fractions per decimate. You can do anything. Is it okay for you? A is it okay for you? If okay, please write in the chat box.

[00:40:14]Now it is a wavy line. How can you measure it? I put the pin. One pin here.

[00:40:34]One pin here.

[00:40:37]One pin here.

[00:40:40]One pin here.

[00:40:43]Okay.

[00:40:46]Now take a thread or wool. Give a knot from the first pin and accordingly I make a uh thread or wool in this way.

[00:40:59]Come to this point and curve this point down this point. go to the next line in this way. fold. Why I use the uh pin?

[00:41:08]Because otherwise we can't measure it in this way. Fold up to this. I take a use a wool or cotton anything or rope anything after what you empty. I understand. Then it cut it a knife full measure you can measure it. It is suppose 15 cm 20 cm anything. In this way we can find out the length of a curvy lines. If it is sc nor normal straight line we can use it by the normal ruler. But if it is a curvy line in that case we use the pen clear look there is a ball. If I tell what is the uh circumference of this one. So how can you do you take a uh cotton or ool anything start from this point and for full this one this one this one and this one your point is finished. Okay now you can understand it is the circumference.

[00:42:21]Clear?

[00:42:31]Daddy is a one box.

[00:42:51]There is another box.

[00:42:56]>> [clears throat] >> You put a ball inside it. Now measure the diameter of the ball. Suppose use a scale.

[00:43:18]This is one line.

[00:43:27]Two line, three line, four line, five line, six line. Now check from 2 to 4 is the diameter of the ball.

[00:43:44]Means 4 - 2 is 2 cm is the diameter.

[00:43:52]What is the diameter in a circle?

[00:43:57]In a circle.

[00:44:01]If you take two points on the circumference and join it and it's come and if it's pass through center point it's a center point it's called the diameter and diameter is the double of the radius means d = 2 r means center to any circumference any point it is called the rad. clear.

[00:44:33]If any doubt, please write in the chat box.

[00:44:43][cough] Thanks everybody who joined in my live classes and thanks Sakara. I want a good result. Bye everybody.