Who Is Heavier

What is weight? Weight tells us how heavy an object is. It is the amount of matter in an object as felt by a scale. In Class 3, we learn to compare weights and to measure them using balances or weighing scales.

Comparing weights — Put two objects on the two pans of a balance. The pan that goes down has the heavier object. If both pans stay level, the objects are equal in weight (same weight).

Measuring weight — We measure weight using units like grams (g) and kilograms (kg). Small things are usually measured in grams and bigger things in kilograms. A spring balance or a pan balance can show how many grams or kilograms an object weighs.

Standard units and conversions — The main relation you need to remember is: 1 kg = 1000 g. So, to change grams into kilograms, divide by 1000. To change kilograms into grams, multiply by 1000.

Adding and comparing weights — You can add weights: if a bag weighs 2 kg and a book 500 g, the total weight is 2 kg + 500 g = 2 kg 500 g (or 2.5 kg). To find how much heavier one object is than another, subtract their weights.

Tips for Class 3 students — Use the balance to compare first (heavier, lighter, equal). Use whole numbers of kg and g or convert to a single unit when adding or subtracting. Practice with everyday objects: fruits, school bag, water bottle.

What is weight? Weight tells us how heavy an object is. We measure weight using units such as kilogram (kg) and gram (g). Example: 1 kg = 1000 g.

How to compare weights — When we want to know which of two or more objects is heavier or lighter, we compare their weights. Words used: heavier than, lighter than, as heavy as (equal weight).

Tools for comparing — Use a balance (pan balance) or a weighing scale. A balance shows which side goes down (the heavier side). A weighing scale gives numerical values so you can compare numbers directly.

Steps to compare two objects — (1) Put one object on each pan of the balance. (2) If one pan goes down, that object is heavier. If both are level, they are equal in weight. Or (1) weigh each object on a scale and (2) compare the numbers: the larger number means the heavier object.

Comparing more than two objects — Find the weights of all objects and then arrange the numbers from greatest to smallest to get heaviest to lightest. You can also compare pairwise using a balance.

Tips for Class 3 — Always note the unit (g or kg) before comparing. If units differ, convert them first (for example, convert kg to g or vice versa) so the numbers are in the same unit.

A pan balance (also called a two-pan balance) is a simple tool used to compare the weights of two objects or to find the weight of an object using known weights. It has two pans hanging from a beam. When the beam is level (horizontal), the weights on both pans are equal. If one pan goes down, the object on that pan is heavier.

Key ideas:

• Compare: Put one object on each pan. Observe which pan goes down. The lower pan holds the heavier object; the higher pan holds the lighter object. If the beam stays level, the two objects weigh the same.
• Weigh with known weights: To find the weight of an object, place it on one pan and put standard weights (e.g., 1 g, 5 g, 10 g, 100 g or 1 kg) on the other pan until the beam is level. The sum of the known weights equals the object's weight.
• Units: We use grams (g) and kilograms (kg). 1000 g = 1 kg. For small classroom objects we usually use grams.

Steps to use a pan balance:

1. Check the balance is empty and the beam is level.
2. Place the first object on the left pan and the second object on the right pan to compare.
3. Look at which side goes down, goes up, or stays level.
4. To measure weight, put the object on one pan and add known weights on the other until balance is horizontal. Add together the values of the known weights to get the object's weight.

Common observations (simple rules):

• If the left pan goes down, left object is heavier.
• If the right pan goes down, right object is heavier.
• If the beam is level, both objects weigh the same.

Precautions: Do not push or touch the pans while reading. Use appropriate standard weights and place them gently. Make sure the balance is on a flat surface.

What are non-standard units of weight?

Non-standard units of weight are everyday objects (like erasers, pencils, pebbles or small bottles) used to compare and measure how heavy something is when standard units (grams, kilograms) are not used. They help young learners understand weight by counting how many identical small items balance an object on a scale or balance.

How to use non-standard units (step-by-step)

• Choose a small object to be the unit (for example, a pencil). Use many identical units so measurements are consistent.
• Place the object to be measured on one side of a balance and add units (pencils) to the other side until the balance is level. Count the number of units required.
• Record the result as: weight of the object = N units (for example, Book = 4 pencils).
• To compare two objects, compare the number of units needed for each. The one needing more units is heavier.

Rules and important points

• Always use the same kind and size of unit for all measurements in that activity (all pencils should be identical).
• Non-standard units give relative measurements. They are useful for comparison but not directly equal to standard units (grams/kg) unless calibrated.
• You can add or subtract weights by adding/subtracting the number of units: if Cup = 3 pencils and Plate = 2 pencils, Cup + Plate = 5 pencils.
• If different non-standard units are used (e.g., bottles and pencils), convert using an equivalence found by weighing (for example, 1 bottle = 3 pencils) before adding or comparing.

Advantages and limitations

• Advantages: simple, hands-on and builds number sense and comparison skills.
• Limitations: not precise, units vary in size/weight, and measurements are only meaningful within the same chosen unit.

What is mass? Mass tells us how much matter is in an object. In everyday life we measure mass to know which thing is heavier or lighter.

Why do we need standard units? Standard units help everyone measure and compare masses in the same way. For Class 3 we use grams (g) and kilograms (kg).

Common standard units: Gram (g) is used for light objects. Kilogram (kg) is used for heavier objects. 1 kilogram is equal to 1000 grams.

How we measure: We use a balance (beam balance), spring scale or digital scale. For comparison, a simple balance tells us which object is heavier by showing which side goes down.

Choosing a unit: Use grams for small items (e.g., a pencil), and kilograms for large items (e.g., a bag of rice). If you need to compare or add masses, convert them to the same unit first.

Simple rule: If a measurement is in kilograms and you want grams, multiply by 1000. If it is in grams and you want kilograms, divide by 1000.

What is estimating?
Estimating means finding a likely value that is close to the actual measurement without measuring exactly. It helps us quickly decide how heavy or light something is.

Common units of mass (weight)
For class 3 we use grams (g) and kilograms (kg). 1 kilogram (kg) = 1000 grams (g). For very heavy things we may use tonne (t): 1 tonne = 1000 kg.

How to estimate weight

• Use known objects as reference: for example, an apple ≈ 100 g, a small notebook ≈ 200–300 g, a full water bottle (1 L) ≈ 1000 g = 1 kg.
• Round to a simple number: if something is about 820 g you can say ≈ 800 g or ≈ 1 kg depending on the situation.
• Compare with similar objects: if a mango feels a bit heavier than an apple (100 g), it might be ≈ 200 g.

How to choose a suitable unit

• If the mass is less than about 1000 g, use grams (g). Example: pencil, apple, toy.
• If the mass is around 1000 g or more, use kilograms (kg). Example: school bag, bag of rice.
• For very heavy things (many kilograms) you can use tonnes (t) in later classes: 1 t = 1000 kg.

Simple rules to decide

• Is the number big in grams (more than 1000)? Then convert to kilograms.
• Is the number small or easy to read in grams (less than 1000)? Keep grams.

Why this helps
Choosing suitable units makes numbers easier to understand and compare. Saying "the bag is 3 kg" is simpler than "the bag is 3000 g".

Mass tells us how heavy something is. In Class 3 we use grams (g) and kilograms (kg). 1 kg = 1000 g. We can compare masses, add masses, subtract masses and convert between kg and g. Always make sure masses are in the same unit before adding, subtracting or comparing.

• Units: gram (g) for small things, kilogram (kg) for heavier things.
• Compare: Convert to the same unit (usually grams) and see which value is larger.
• Add/Subtract: Convert to the same unit. For kg and g together, add grams first, carry 1000 g = 1 kg if needed. For subtracting, borrow 1 kg = 1000 g when grams are not enough.
• Using a balance or weighing scale: A balance shows which side is heavier. A scale gives the mass directly (in g or kg).

Steps for solving problems:

1. Read the problem and note units.
2. If units differ, convert so all masses use the same unit (either all g or all kg+g format).
3. Add or subtract as required. When adding grams, if total grams ≥ 1000, convert 1000 g to 1 kg and add to the kg part. When subtracting and grams in minuend are less than in subtrahend, borrow 1 kg (1000 g).
4. Write the answer in kg and g or in grams depending on the question.

Activities and exercises in the Class 3 chapter "Who is Heavier?" help children learn how to compare and measure the weight of everyday objects. The main ideas are: use words heavier, lighter and equal; use a pan-balance or weighing scale to compare weights; record weights in grams (g) and kilograms (kg); order objects by weight; and find how much heavier one object is than another.

Simple classroom activities:

• Activity 1 — Using a pan-balance: Place one object on each pan to see which pan goes down. The lower pan holds the heavier object. If both pans stay level, the objects weigh the same.
• Activity 2 — Using a weighing scale: Weigh objects (fruits, books, water bottles). Record the readings in a table. Compare the numbers to decide which is heavier or lighter.
• Activity 3 — Ordering by weight: Arrange several objects from lightest to heaviest and explain why.
• Activity 4 — Difference in weight: Subtract the smaller weight from the larger to find how much heavier one object is than another (Heavier − Lighter = Difference).
• Activity 5 — Estimation and check: Guess which object is heaviest, then weigh to check your guess. This improves number sense and estimation skills.

How to do an exercise step-by-step:

1. Choose objects to compare and name them (e.g., apple, book, water bottle).
2. Decide whether to use a balance (gives comparative result) or a scale (gives numeric weight).
3. If using a scale, note the weight in grams or kilograms and write it in a table.
4. Compare the recorded numbers to label each object heavier, lighter, or equal. To find how much heavier, subtract the smaller weight from the larger one.
5. Answer questions such as: Which is the heaviest? Which is the lightest? How much heavier is X than Y?

Tips for teachers and parents: choose safe, varied household objects; use standard weights or a simple kitchen scale; encourage children to say full sentences: "The book is heavier than the pen." and guide them to check answers by re-measuring or using a balance for comparison.