Accurate Measurement of Length
What to do when the starting end of a ruler cannot be used
If the zero mark or the starting point of the ruler is not clear or if the ruler is broken at that end, start measuring from the next clearly visible number. By subtracting that initial number from the final reading, you can obtain the exact length of the object.
Simple Explanation
1. What is the problem?
Normally, we start measuring from the 0 mark of a ruler.
But sometimes the 0 mark may not be clearly visible. The ruler may also be broken or damaged at its starting end.
In such a case, we should not depend on that unclear or broken starting point.
2. Where should we start measuring?
Look along the ruler and find the next number that can be seen clearly.
Use this clearly visible number as the initial reading and begin the measurement there.
3. What is the final reading?
After placing the object correctly, look at the ruler marking where the other end of the object reaches.
This reading is the final reading.
4. Can we take the final reading directly as the length?
No. In this situation, measurement did not begin from zero. It began from another number on the ruler.
Therefore, the starting number must be subtracted from the final reading.
Meanings
| Meanings | Marathi Arth | Hindi Arth |
|---|---|---|
| Zero mark — the 0 marking on a ruler | शून्याची खूण | शून्य का निशान |
| Starting point — the point from where measurement begins | सुरुवातीचा बिंदू | प्रारंभिक बिंदु |
| Clear — easy to see properly | स्पष्ट | स्पष्ट |
| Broken — damaged or having a part missing | तुटलेले | टूटा हुआ |
| Clearly visible — able to be seen properly | स्पष्टपणे दिसणारे | स्पष्ट रूप से दिखाई देने वाला |
| Initial number — the number from where measurement is started | सुरुवातीची संख्या | प्रारंभिक संख्या |
| Final reading — the ruler reading at the other end of the object | अंतिम मोजमाप | अंतिम माप |
| Subtracting — taking one number away from another | वजाबाकी करणे | घटाना |
| Exact length — the correct length of the object | अचूक लांबी | सटीक लंबाई |
Can the circumference of a ball or a large jar be measured with a ruler?
The length of a curved surface can be
measured using a thread.
Simple Explanation
1. What is the difficulty with a curved object?
A ball or a large jar has a curved surface.
The distance around such an object is called its circumference.
2. Why is a straight ruler not convenient?
A ruler is straight and rigid. A curved surface bends around the object.
Therefore, a straight ruler cannot conveniently follow the complete curved path around the object.
3. Why can thread be used?
A thread is flexible. It can bend and follow the curved surface of an object.
Therefore, the length along a curved surface can be measured with the help of a thread, as shown in the textbook illustration.
Meanings
| Meanings | Marathi Arth | Hindi Arth |
|---|---|---|
| Circumference — the distance around an object | परिघ | परिधि |
| Ball — a round object used in games | चेंडू | गेंद |
| Jar — a container with a wide body | बरणी | जार / मर्तबान |
| Curved — bent and not straight | वक्र / वाकलेले | वक्र / मुड़ा हुआ |
| Curved surface — a surface that bends around | वक्र पृष्ठभाग | वक्र सतह |
| Thread — a thin flexible strand | धागा | धागा |
| Flexible — able to bend easily | लवचिक | लचीला |
Reference Point
Playgrounds must be marked for sports competitions. Each sports field has a specific length and breadth. Your sports teacher uses a metre tape to mark the boundaries for each sport as shown in the adjoining picture.
Simple Explanation
1. Why must playgrounds be marked?
For sports competitions, the playing area has to be properly marked.
The markings help show the required area and boundaries of the sports field.
2. Are all sports fields the same size?
Each sports field has its own specific length and breadth.
Therefore, the field must be measured according to the required length and breadth of that particular sport.
3. How does the sports teacher mark the field?
The sports teacher uses a metre tape to take the required measurements.
Using these measurements, the boundaries for the sport are marked on the playground.
Meanings
| Meanings | Marathi Arth | Hindi Arth |
|---|---|---|
| Reference Point — a fixed point used as a basis for measurement | संदर्भ बिंदू | संदर्भ बिंदु |
| Playground — an area used for playing games | खेळाचे मैदान | खेल का मैदान |
| Marked — shown by making lines or boundaries | खुणा केलेले / चिन्हांकित | चिह्नित किया गया |
| Sports competition — an event in which people compete in sports | क्रीडा स्पर्धा | खेल प्रतियोगिता |
| Specific — particular and fixed for a purpose | विशिष्ट | विशिष्ट |
| Length — measurement from one end to another | लांबी | लंबाई |
| Breadth — measurement from one side to the other | रुंदी | चौड़ाई |
| Metre tape — a measuring tape used to measure length or distance | मीटर मोजपट्टी | मीटर मापने का फीता |
| Boundaries — lines showing the limits of an area | सीमा / सीमारेषा | सीमाएँ / सीमा रेखाएँ |
| Adjoining picture — the picture placed nearby | शेजारील चित्र | पास दिया गया चित्र |
Whenever a distance is measured, it is measured from a fixed object or a specific point. This point is called a ‘Reference Point’.
Simple Explanation
1. When measuring distance, where do we begin?
A distance is measured from somewhere. We need a definite place from which the measurement begins.
The textbook says that this starting basis can be a fixed object or a specific point.
2. What does “fixed object” mean here?
It means an object whose position is fixed and can be used as the place from which the distance is measured.
3. What does “specific point” mean?
Instead of using an object, we may use one particular, clearly decided point as the place from which the distance is measured.
4. What is this fixed object or specific point called?
The fixed object or particular point from which we measure the distance is called the Reference Point.
So, the reference point tells us from where the distance is being measured.
Meanings
| Meanings | Marathi Arth | Hindi Arth |
|---|---|---|
| Whenever — every time something happens | जेव्हा जेव्हा | जब भी |
| Distance — the space between two points or places | अंतर | दूरी |
| Measured — found by using a measuring method | मोजलेले | मापा गया |
| Fixed — kept at one decided position | निश्चित / स्थिर | निश्चित / स्थिर |
| Fixed object — an object at a fixed position used as the basis for measurement | निश्चित वस्तू | निश्चित वस्तु |
| Specific — particular and clearly decided | विशिष्ट | विशिष्ट |
| Specific point — one particular decided point | विशिष्ट बिंदू | विशिष्ट बिंदु |
| Reference Point — the fixed object or specific point from which distance is measured | संदर्भ बिंदू | संदर्भ बिंदु |
In the game of Kho-Kho, there is a fixed distance between two poles. While marking the field, the first fixed pole serves as the reference point for the second pole.
Simple Explanation
1. What has to be fixed in a Kho-Kho field?
In Kho-Kho, there are two poles and there is a fixed distance between them.
Therefore, while marking the field, the second pole cannot be placed at any random distance from the first pole.
2. Which pole is fixed first?
While the field is being marked, the first pole is fixed first.
Once its position is fixed, it provides a definite place from which the position of the second pole can be decided.
3. Why does the first pole become the Reference Point?
The required distance for the second pole is measured from the first fixed pole.
Therefore, the first fixed pole acts as the Reference Point for the second pole.
4. What should you understand from this example?
The reference point gives us a fixed place from which the distance is measured.
In this Kho-Kho example, that fixed place is the first pole. The position of the second pole is determined using the required distance from this reference point.
Meanings
| Meanings | Marathi Arth | Hindi Arth |
|---|---|---|
| Kho-Kho — a team game played between two teams | खो-खो | खो-खो |
| Fixed distance — a distance that is already decided | निश्चित अंतर | निश्चित दूरी |
| Pole — a long upright post | खांब | खंभा |
| Marking the field — measuring and showing the required field positions | मैदानाची आखणी करणे | मैदान को चिह्नित करना |
| First fixed pole — the pole whose position is fixed first | पहिला निश्चित खांब | पहला निश्चित खंभा |
| Serves as — works or acts as something | म्हणून कार्य करते | के रूप में कार्य करता है |
| Reference Point — a fixed point from which distance is measured | संदर्भ बिंदू | संदर्भ बिंदु |
| Second pole — the other pole whose position is fixed using the required distance | दुसरा खांब | दूसरा खंभा |
On highways connecting major cities, there are boards or stones (milestones) indicating the distance to the next big town. From which specific location in the town is the distance measured? Collect the information.
Simple Explanation
1. What do we see on highways?
On highways connecting major cities, we can see boards or stones called milestones.
These show the distance to the next big town.
2. What question does the textbook ask?
A town covers an area, but the distance shown on a milestone must be related to some specific location.
The activity asks you to find out which specific location in the town is used when this distance is stated.
3. What information do you have to collect?
You have to find the particular location from which the displayed distance to the town is considered or measured.
The textbook asks you to collect this information rather than simply giving you the answer.
Meanings
| Meanings | Marathi Arth | Hindi Arth |
|---|---|---|
| Highway — a main road connecting places | महामार्ग | राजमार्ग |
| Connecting — joining one place with another | जोडणारा | जोड़ने वाला |
| Major cities — large or important cities | प्रमुख शहरे | प्रमुख शहर |
| Milestones — roadside stones or markers showing distance | मैलाचे दगड / अंतरदर्शक दगड | मील के पत्थर |
| Indicating — showing or giving information about something | दर्शविणारे | दर्शाने वाला |
| Distance — the space between two places or points | अंतर | दूरी |
| Specific location — one particular fixed place | विशिष्ट स्थान | विशिष्ट स्थान |
| Measured — found using a measurement | मोजलेले | मापा गया |
| Collect information — find and gather the required information | माहिती गोळा करणे | जानकारी एकत्र करना |