Grade 2 → Measurement and Data → Weight and Mass Measurement ↓
Comparing Weights of Objects
In Class 2, students begin to learn about the concept of weight and how to compare the weight of different objects. Weight is how heavy something is. Anything around us can have weight, whether it's a small pencil or a large car. Understanding how weight works can help us make decisions in everyday life, such as when we choose whether to carry a backpack or a shopping bag.
Weight is often measured in units such as grams and kilograms, but for this level, we will focus more on the idea of comparing rather than measuring weight precisely. Comparing weight is about deciding whether one object is heavier, lighter, or the same weight as another object.
Understanding weight
The weight of an object indicates how heavy it is. Typically, people use tools such as scales or balances to measure weight, but these tools may be too complicated for grade 2 students. Instead of measuring weight using numbers, students at this level can compare weights using observation and simple tools such as balance scales.
Balance scale method
One of the simplest devices that helps us compare the weight of two objects is the balance scale. A balance scale has two pans, and when you place an object on each pan, it can tell you which object is heavier or whether they weigh the same.
Example of a balance scale:
If one side of the scale goes down then it means that the object is heavy. If both the sides remain flat then the weight of the objects is almost the same.
Comparing different items
To compare the weight of different objects without scales, you can do the following:
- Hold an object in each hand and see which object feels heavier.
- Think about the size and material of the items. Often, larger items or items made of certain materials are heavier.
Visual example:
Comparison of a book and a pencil:
In this example, the book is placed on one side and the pencil on the other. Intuitively, we might think that the book is heavier than the pencil because it is larger and made of thicker material.
Another visual example:
Comparison of an apple and a feather:
Here, the apple looks heavier than the feather, because fruits such as apples usually weigh more than lighter objects such as feathers.
Words to know
- Heavier: An object is heavier if it pulls down more than another object.
- Lighter: An object is lighter if it exerts less drag than another object.
- Approximately equal weight: Two objects have approximately the same weight when pulled down with the same force.
Using words to compare
When comparing weights without scales, you can use descriptive language to clarify your ideas, such as:
- "The stone is heavier than the leaf."
- "The paper is lighter than the box."
- "Both the toy cars weigh almost the same."
Practical activities
Activity 1: Weight observation
Gather some items from around the house, such as a spoon, eraser, small toy and book. Compare with your hands which one is heavier or lighter, and arrange them in order from lightest to heaviest. Talk with an adult or your classmates about why you think an object is light or heavy based on size and material.
Activity 2: Balance scale experiment
Find a simple balance scale, or make one using a ruler, string and cups. Place different items on each side, starting with easy comparisons like a pebble vs. a leaf. Watch how the balance changes and start predicting outcomes before placing each item on the scales. Write down your predictions and check if they were correct.
Other thoughts
It is important for students to recognize that some objects may seem heavy but are actually light (such as a large but empty plastic container) and others may seem small but are quite heavy (such as a metal weight). Digging deeper into what went into making objects is also an exciting way to understand why they may be heavy or light.
Funny weight comparison
Here are some fun examples that you can discuss or reflect on with your friends:
- Is the balloon heavier or lighter than the paper clip?
- If you are both grown up, would you prefer to hold a pebble or a pillow?
- If you fill one box with feathers and another box with bricks of the same size, which brick will be heavier?
Summary
Comparing the weight of objects is all about observation and reasoning. In Grade 2, the goal is to help students recognize relationships between the appearance of objects and their weight using categories such as heavy, light, and equal weight. This foundational skill is practical as well as serves as a cornerstone for future learning about weights and measurements.
Practice
- Write down five things in your bag. Guess which is the heaviest and which is the lightest.
- Find two objects that weigh approximately the same. How do you know if they weigh the same?
- Find a total of ten objects with a friend. Use a scale to check which objects are heavy or light and list them in order from lightest to heaviest.