NCERT Class 4 Mathematics Maths Mela Chapter 08 Weigh It Pour It PDF Download

Chapter 8: Weigh It, Pour It

In Grade 3, we learnt about measuring weight and capacity. Do you remember the 1 kilogram salt packet and 1 litre bottle? Let us learn some more about measuring weight and capacity.

1. Look at the pictures given and write the names of the animals from heaviest to lightest. _____________________________________________________________
2. Write the name of the heaviest object in your home. How did you know? ___________________________________________________________
3. Do you carry your school bag with ease or with some effort? ____________________________________________________________
4. Write the name of the heaviest book in your bag. How did you know? _______________________________________________________________
5. What is your weight? How did you know? _________________________________________________________________

Fun at Vegetable Market!

Rita and Shabnam went to the market to buy some fruits and vegetables. They saw the vegetable seller weighing vegetables.

What do you think will be the weight of the half pumpkin? ________

Teacher's Note

When you estimate weight, start by thinking of something familiar - like knowing that a 1 kg salt packet feels heavy or light in your hand. Then compare the object you are weighing to that feeling. For example, does a half pumpkin feel heavier or lighter than the salt packet you remember? Using this familiar anchor helps you make better estimates.

Let Us Do

Estimate the weight of the following and put a tick mark (\( \checkmark \)) in the appropriate cell. Try to verify if your guess is correct by using a weighing balance.

We often write kg for kilogram and g for gram

Let Us Explore

1. Look at the pictures. You may also try doing the same.

a.

[Figure: 2 packets of 500 grams balanced on a scale, showing 1000 g = 1 kg, See in your textbook]

\[ 2 \text{ packets of } 500 \text{ grams} = 1000 \text{ g} = 1 \text{ kg} \]

\[ \text{So, } 1 \text{ packet of } 500 \text{ g} = \frac{1}{2} \text{ kg} \]

\[ \text{Or } 500 \text{ g} = \frac{1}{2} \text{ kg} \]

b.

[Figure: 4 packets of 250 grams balanced on a scale, showing 1000 g = 1 kg, See in your textbook]

\[ 4 \text{ packets of } 250 \text{ grams} = 1000 \text{ g} = 1 \text{ kg} \]

\[ \text{So, } 1 \text{ packet of } 250 \text{ g} = \frac{1}{4} \text{ kg} \]

\[ \text{Or } 250 \text{ g} = \frac{1}{4} \text{ kg} \]

c.

[Figure: 10 packets of 100 grams balanced on a scale, showing 1000 g = 1 kg, See in your textbook]

\[ 10 \text{ packets of } 100 \text{ grams} = 1000 \text{ g} = 1 \text{ kg} \]

Let Us Find

1. How many 250 g daal packets will balance one 500 g daal packet? Draw as many packets of 250 g on the empty pan such that it balances the 500 g packet shown on the left pan of the balance. What did you find? \[ 250 \text{ g} = \text{__________ of } 500 \text{ g} \left( \frac{1}{2}, 2 \right) \]
2. Draw arrows to indicate which side the pan balance will tilt? One is shown for you. a. [Figure: Pan balance with salt packet on right side and multiple sugar packets on left side, See in your textbook]b. [Figure: Pan balance with salt packet on right side and purple fabric on left side, See in your textbook]c. [Figure: Pan balance with salt packet on right side and multiple yellow boxes labeled "Haldi" on left side, See in your textbook]d. [Figure: Pan balance with salt packet on right side and multiple green boxes labeled "Tea Leaves" on left side, See in your textbook]
3. Match the unit convenient for measuring each of the following objects?[Figure: Baby, eraser, purple book, pushpin, paperclip, feather, table, refrigerator, pen, and wristwatch with two columns below labeled "Kilograms" and "Grams", See in your textbook]

Note for Teachers: You could try to organise a weighing balance in grade and weights like 100 g, 500 g, 1 kg. You could also ask children to do this task at home or in their neighbourhoods.

[Figure: 10 erasers labeled 10 g each arranged in two rows of five, See in your textbook]

1. How many erasers will weigh the same as a 50 g Haldi packet?______
2. A 100 g soap bar will weigh the same as __________ erasers.
3. _________ erasers will weigh the same as 250 g sugar.

Teacher's Note

When working with fractions and weight, remember that \( \frac{1}{2} \) of 500 g means you divide 500 by 2, which gives 250 g. Similarly, 4 packets of 250 g make 1000 g because you multiply: \( 4 \times 250 = 1000 \). Always identify what the question is asking - do you need to multiply the weight or divide it?

Let Us Think

Boxes of Sweet

Mr Shrinathan, a sweet shop owner has several orders for 1 kg Kaju-katli but he has to pack them in different sized boxes.

Write down the number of boxes needed to pack 1 kg Kaju-katli in the blank space:

1. Mr Das wants the sweets in boxes weighing 500 g each. _____________
2. Mrs Fernandes wants the sweets in boxes weighing 250 g each. ______________
3. Mrs Khan wants the sweets in boxes weighing 100 g each. ____________
4. Mr Patel wants the sweets in boxes weighing 50 g each. ___________

Key Points

• Weight is measured in kilograms (kg) and grams (g). One kilogram equals 1000 grams: \( 1 \text{ kg} = 1000 \text{ g} \).
• Fractional parts of a kilogram can be expressed as grams. For example, \( \frac{1}{2} \text{ kg} = 500 \text{ g} \), \( \frac{1}{4} \text{ kg} = 250 \text{ g} \), and 100 g is \( \frac{1}{10} \) of a kilogram.
• A balance scale is used to compare the weights of two objects. The side with the heavier object tilts down, and when both sides have equal weight, the balance stays level.
• Use kilograms to measure heavy objects like people, furniture, and bags of groceries, and use grams to measure lighter objects like erasers, books, and small packets.

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