Who is Heavier? - Using a Simple Balance

Understanding Weight: Weight measures how heavy or light an object is. In daily life, we see that objects like a feather are light, while objects like a large stone are heavy. On a simple balance, the pan holding the heavier object will always be lower than the pan holding the lighter object.

Units of Measurement (Grams and Kilograms): We use Grams ($g$) to measure light objects, such as a pencil, a biscuit, or a gold ring. We use Kilograms ($kg$) to measure heavier objects, such as a school bag, a sack of rice, or a human being.

Conversion Rule: The standard relationship between the two units is that $1000$ grams make up $1$ kilogram. This is written as $1 \text{ kg} = 1000 \text{ g}$. Understanding this helps us compare weights given in different units.

Visualizing the Simple Balance: A simple balance consists of two pans hanging from a central beam. If you imagine a see-saw at the park, the heavier person goes down and the lighter person goes up. The simple balance works the same way: the pan with more weight sinks towards the ground.

The Concept of Equilibrium (Balancing): When the amount of weight in the left pan is exactly equal to the weight in the right pan, the beam stays perfectly horizontal and the pans stay at the same level. This state is called being 'balanced'.

Standard Weights: To measure how much an object weighs, shopkeepers use metal blocks of fixed weights like $100 \text{ g}$, $250 \text{ g}$, $500 \text{ g}$, $1 \text{ kg}$, and $2 \text{ kg}$. They place the object in one pan and keep adding these weights to the other pan until the balance is level.

Estimation of Weight: Before using a balance, we can guess which object is heavier by looking at its size and the material it is made of. However, size can be misleading; for example, a small iron ball is much heavier than a large cotton pillow.

Adding and Subtracting Weights: When multiple items are placed in one pan, their weights are added together to find the total weight. For example, if you have two packets of $500 \text{ g}$ sugar, the total weight is $500 + 500 = 1000 \text{ g}$, which is equal to $1 \text{ kg}$.