How Heavy How Light Chapter Notes | Mathematics for Class 4: NCERT PDF Download

Introduction

 Today, we're diving into the fascinating world of weight. Have you ever wondered why some objects feel heavier than others, or how we measure the heaviness of things? Well, that's what we'll be exploring together! Understanding weight is important because it helps us make sense of the world around us, from measuring ingredients for baking delicious treats to lifting objects safely

Heavier Vs Lighter

Weight comparison involves determining which object is heavier or lighter when comparing two or more objects. Children learn to use terms like "heavier" and "lighter" to describe the relationship between objects based on their weights, developing a sense of weight through observation and activities.

Making Weights

Making weights using grains equal to weight involves creating small units of weight by measuring out grains or other small objects until they reach a desired weight. This process allows you to make improvised weights for measuring objects on a balance scale or for other purposes where precise measurements are needed. For example, if you need a weight of 100 grams, you can carefully measure out grains until you have a collection that weighs exactly 100 grams. 

Grams and Kilograms

Converting between kilograms (kg) and grams (g) involves multiplying or dividing by 1000, as there are 1000 grams in 1 kilogram. To convert from kilograms to grams, you multiply the number of kilograms by 1000. For example, 2 kilograms is equal to 2 × 1000 = 2000 grams. To convert from grams to kilograms, you divide the number of grams by 1000. For example, 5000 grams is equal to 5000 ÷ 1000 = 5 kilograms. This conversion allows you to express weights in different units depending on the level of precision required.

Which is heavier

Determining which object is heavier involves comparing their weights. If one object has a greater weight than another, it is considered heavier. You can use a balance scale or simply lift the objects to feel their weight and make the comparison. When comparing weights, it's important to use a consistent unit of measurement, such as kilograms or grams, to ensure accuracy.

Shopping

To find the total payable amount for a purchase based on the price per kilogram (kg), you multiply the price per kilogram by the number of kilograms purchased. This calculation gives you the total cost for the entire quantity purchased. For example, if the price per kilogram is $5 and you buy 3 kilograms of an item, the total payable amount would be $5/kg × 3 kg = $15. This method allows you to calculate the total cost efficiently based on the weight of the items purchased and the price per kilogram.

How much the chair weight ?

To determine the weight of a chair, you need to physically weigh it using a scale or balance. Place the chair on the scale and read the weight displayed. Chairs can vary significantly in weight depending on factors such as the materials used, size, and design. If you don't have access to a scale, you can estimate the weight by comparing it to objects of known weight or by lifting it to gauge its heaviness. However, for accurate measurements, using a scale is recommended.

Broken Stones

To weigh a broken part of a stone, place it on a scale and read the measurement displayed. Record the weight in kilograms (kg) or grams (g) for various purposes, such as calculating shipping costs or assessing its value.

Post office

At the post office, deliveries are weighed using a scale. Packages are placed on the scale, which measures their weight in units like kilograms (kg) or grams (g). This weight is then used to calculate postage costs based on destination and mailing service. Understanding how packages are weighed helps us learn about measurement and the mailing process.

Our weight together

1. Determine the weight of each person. This can be done by using a scale or balance to measure their weight in kilograms (kg) or pounds (lb).

2. Add together the weights of the 2-3 people to find the total weight. For example, if person A weighs 60 kg, person B weighs 70 kg, and person C weighs 80 kg, the total weight would be 60 kg + 70 kg + 80 kg = 210 kg.

3. 

Am I fit or fat ?

Determining if someone is fit based on weight involves considering whether their weight falls within a healthy range for their age and height. 

How many oranges?