CLASS 6TH DAY 4
INTRODUCTION
Motion and Measurement
Measurement: Comparing an unknown quantity with some known quantity is called measurement.
Result of Measurement: The result of measurement has two parts; one part is the number and another part is the unit. The known quantity which is used in measurement is called a unit. For example; when you say that your height is 150 cm then the measurement of your height is being expressed in a number, i.e. 150 and a unit, i.e. centimeter.
Arbitrary Units of Measurement: Before the development of standard units of measurement, people used arbitrary units of measurement. Some of them are still in use at some places. Handspan, finger-length, cubit (length between the elbow and finger tips), foot-length and arms-length are some examples of arbitrary units of measurement.
Disadvantages of Arbitrary Units of Measurement: You have seen that arbitrary units are made up of lengths of different body parts. These lengths can vary from one person to another. This can create lot of confusion as there would be no uniformity in measurement.
Standard Unit of Measurement:
To maintain uniformity in measurement, standard units of measurement were introduced in different parts of the world at different places. Napoleon is believed to have introduced most of the standard units of measurement which are being used today.
SI Unit (International System of Units): It is the most widely used system of measurement in the world. It is based on MKS (Meter-Kilogram-Second) System. Length, weight and time are considered as basic quantities for measurement and other quantities are derived from them. As per SI system; the unit of length is meter, unit of weight is kilogram and the unit of time is second. Barring the unit of time, other units of this system are based on decimal system. Use of the decimal system makes the SI Unit more user-friendly.
Direct Measurement: When we measure some quantity directly, it is called direct measurement. For example; when you are using a ruler to measure a length, you are doing direct measurement.
Indirect Measurement: When we measure some quantity indirectly, it is called indirect measurement. For example; when you have to measure the girth of a tree or the length of a curve, you cannot use a ruler. You can use a rope to find the length of a curved line and then compare the length on a ruler.
Correct Steps of Measuring the Length:
- The scale should be placed along the length of the object to be measured.
- The zero mark of the scale should be taken as the beginning point. If zero mark is broken or invisible, then any other mark should be selected and final adjustment should be made accordingly. For example; if you begin from 1 and the final reading is 14 then actual reading would be 14 – 1 = 13.
- Correct eye position should be maintained. The eye position should be just above the point to be measured. Incorrect eye position leads to parallax error and gives incorrect reading.
A metric prefix is a unit prefix that precedes a basic unit of measure to indicate a multiple or fraction of the unit. While all metric prefixes in common use today are decadic, historically there have been a number of binary metric prefixes as well.[1] Each prefix has a unique symbol that is prepended to the unit symbol. The prefix kilo-, for example, may be added to gram to indicate multiplication by one thousand: one kilogram is equal to one thousand grams. The prefix milli-, likewise, may be added to metre to indicate division by one thousand; one millimetre is equal to one thousandth of a metre.
Motion: The change in position of an object with change in time is called motion.
Types of Motion:
Can you answer this interesting question? How many things are currently moving around you? I am pretty sure there will be a thing or two besides you moving in some way or the other! In this video, as well as in the upcoming ones we will talk about common ways in which things move, or common types of motion! We will start by defining motion in this video!
Linear Motion: When the motion is in a straight line, it is called linear motion, e.g. a car moving on a straight road.
Curvilinear Motion: When the motion is on a curved path, it is called curvilinear motion, e.g. a car moving on a bend.
Circular Motion: When the motion is on a circular path, it is called circular motion, e.g. the motion of the earth in its orbit.
Periodic Motion: When the motion is repetitive after a fixed interval, it is called periodic motion, e.g. motion of a wing
DIRECTIONS
Imagine you are walking on the road and an elderly man asks you the direction to a nearby park. So how will you guide him to the park? Watch this video to learn more.👇 👇
Here is a small quiz to test your understanding. Try to attempt all the questions and get the highest marks possible.👇 👇
FUN ACTIVITY (REVERSI)
Each of the disks’ two sides corresponds to one player; they are referred to here as light and dark after the sides of Othello pieces, but any counters with distinctive faces are suitable. The game may for example be played with a chessboard and Scrabble pieces, with one player letters and the other backs.
The historical version of Reversi starts with an empty board, and the first two moves made by each player are in the four central squares of the board. The players place their disks alternately with their colors facing up and no captures are made. A player may choose to not play both pieces on the same diagonal, different from the standard Othello opening. It is also possible to play variants of Reversi and Othello where the second player’s second move may or must flip one of the opposite-colored disks (as variants closest to the normal games).
For the specific game of Othello (differing from the historical Reversi), the rules state that the game begins with four disks placed in a square in the middle of the grid, two facing white side up, two pieces with the dark side up, with same-colored disks on a diagonal with each other.
Convention has initial board position such that the disks with dark side up are to the north-east and south-west (from both players’ perspectives), though this is only marginally meaningful to play (where opening memorization is an issue, some players may benefit from consistency on this). If the disks with dark side up are to the north-west and south-east, the board may be rotated by 90° clockwise or counterclockwise. The dark player moves first.