Lesson 103: Comparing weights and volumes

🧮 MATH (40 Lessons) • 🟡 C. Shapes and Measurement

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Objective

I can compare how heavy or light objects are and how much containers can hold. I can use words like heavy, light, heavier, lighter, full, empty, holds more, and holds less. I also hear the unit names grams (g), kilograms (kg), and liters (L).

Materials

Mini-lesson — Comparing weights and how much things hold

In this lesson, we compare how heavy things are and how much they can hold. We use real objects that children see every day.

Heavy and light

  • Some things are light (like a feather or an empty paper cup).
  • Some things are heavy (like a full water bottle or a bag of books).
  • We say one object is heavier than or lighter than another object.

Balance scales

  • A balance scale has two pans.
  • If one side goes down, that side is heavier.
  • If one side goes up, that side is lighter.

Full, empty, and how much containers hold

  • Containers like cups, bottles, and jugs can be full, half full, or empty.
  • We say one container holds more or holds less than another.
  • A tall bottle might hold more than a small cup, even if both look full.

Simple units we see in real life

  • On food packets, we see g (grams) and kg (kilograms) for weight.
  • On drink bottles, we see L (liters) or ml (milliliters) for how much liquid they hold.
  • For this level, children just notice these labels and use them to talk about heavier / lighter and holds more / holds less.

In this lesson, focus on comparing two objects at a time: which one is heavier, which one is lighter, and which container holds more or holds less.

Picture strip: Balance scale and containers.

Balance scale — heavy vs light

Containers — full and empty

Guided Practice — Real objects for weight and how much they hold

You will use real objects from your classroom or home. First, feel which ones are heavier or lighter. Then use the tracing pad to write the most important measurement words.

  1. Pick two objects to compare: For example, choose a full water bottle and an empty bottle, or a small cup and a large jug.
  2. Feel the weight: Hold one object in each hand. Notice which one feels heavier and which one feels lighter.
  3. Think about how much they hold: Look at the shapes and sizes. Decide which container holds more and which holds less.
  4. Write the key words: On your paper or notebook, write these words in a list:
    • heavy • light • full • empty • holds more • holds less
  5. Look at the labels (if there are any): If your packet or bottle has writing on it, find numbers like 500 g, 1 kg, or 1 L. These are units that tell how much something weighs or how much it holds.
  6. Use the tracing pad: Choose two words that match your objects (for example, heavy and light or full and empty) and trace them on the tracing pad.
  7. Add a small picture: Next to each word, draw a tiny picture that matches it, such as a full bottle for full or an empty cup for empty.
Tracing Pad
Tracing snapshot for print
Tip: After you trace words like heavy and light, you can write a short sentence such as "The full bottle is heavy." and draw a matching picture.

Practice 1 — Comparing weights

[PLACEHOLDER PRACTICE 1]

Practice 2 — Comparing volumes (how much a container holds)

[PLACEHOLDER PRACTICE 2]

Practice 3 — Using the unit names

[PLACEHOLDER PRACTICE 3]

Quick Check — Comparing weights and volumes

Answer each question about heavy and light, full and empty, and the unit names grams (g), kilograms (kg), and liters (L). You may look back at the mini-lesson.

1) Which object is usually lighter?

A pencil is a small, light object.

2) Which object is usually heavier?

A textbook weighs more than a paper clip or a feather.

3) When we measure how heavy something is, we use units like:

Grams and kilograms are names of units for weight.

4) When we measure how much liquid a container can hold, we use units like:

Liters are used for liquids like water, milk, or juice.

5) Which container most likely holds more?

A big bottle has room for more liquid than a cup or spoon.

6) Which word means the container has nothing inside?

Empty means there is nothing inside the container.

7) Which word means the container is filled to the top?

Full means there is no more space inside.

8) A leaf and a stone are on the table. Which one is lighter?

A leaf is much lighter than a stone.

9) A full backpack and an empty backpack are on the floor. Which is heavier?

When we add books, the backpack becomes heavier.

10) Which of these is most likely measured in liters (L)?

Orange juice is a liquid, so we think about liters.

11) Which of these is most likely measured in kilograms (kg)?

A heavy suitcase is a good example of something measured in kilograms.

12) Which of these is most likely measured in grams (g)?

Small, light things like chocolate bars are often measured in grams.

13) Your teacher asks, “Which cup holds less water?” What should you look for?

A smaller cup can hold less liquid than a large one.

14) Which sentence is true?

When we add water, we add weight, so the full bottle is heavier.

15) Why do we learn unit names like grams, kilograms, and liters?

Unit names help us describe weight and volume clearly.

Assessment (parent/teacher)

Exit ticket (student)

Next time I will practise…

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