⚖️ Measuring Mass
Mass tells us how heavy something is. Let's find out which objects are heavier or lighter using a balance scale!
⚖️ Heavier and Lighter
Mass is how heavy something feels when you pick it up. We use the words heavier and lighter to compare two objects.
HEAVIER
A rock is heavier than a feather. It takes more effort to lift.
LIGHTER
A feather is lighter than a rock. It is easy to lift.
We can also say: "The rock has MORE mass than the feather."
⚖️ Using a Balance Scale
A balance scale has two pans. The heavier side goes DOWN. The lighter side goes UP. When both sides are equal, the scale is balanced.
Pivot point
The rock side goes down — the rock is heavier than the feather.
If both pans are level, the two objects have the same mass!
🧱 Measuring with Non-Standard Units
Before we had standard units like kilograms, people used everyday objects to measure mass — like blocks, marbles, or dried beans! We call these non-standard units.
Example: Using blocks
Place a toy on one side of the balance scale. Add blocks to the other side until the scale balances. Count the blocks — that is the mass of the toy!
The toy train has a mass of about 5 blocks. ✅
Worked Examples
Example 1: Which is heavier?
A bag of potatoes or a tennis ball — which is heavier?
A bag of potatoes is heavier. It would make the balance scale tip down on its side. ✅
Example 2: Balance scale reading
A book balances with 8 counters. A pencil case balances with 5 counters. Which is heavier?
The book is heavier — it needed more counters (8 > 5). ✅
Example 3: Order by mass
A stapler (12 blocks), a ruler (4 blocks), scissors (9 blocks). Order from lightest to heaviest.
Lightest → Heaviest: ruler (4), scissors (9), stapler (12). ✅
Key Vocabulary
How heavy an object is.
Words we use to compare the mass of two objects.
A tool with two pans used to compare masses.
An everyday object (like a block) used to measure mass.
Knowledge Check
Question 1: A watermelon and a grape are put on a balance scale. Which side goes DOWN?
Question 2: A shoe balances with 10 blocks. A sock balances with 3 blocks. Which is heavier?
Question 3: What happens to the scale when both sides have the same mass?
Question 4: Which of these is a non-standard unit for measuring mass?
Question 5: A cat (18 blocks), a mouse (3 blocks), a rabbit (11 blocks). Which animal is the lightest?
Pax Says:
"Try lifting two objects at home and compare! Hold one in each hand and feel which is heavier. You are measuring mass with your hands!"
Key Concepts Summary
- ✓ Mass is how heavy an object is.
- ✓ Heavier objects make the balance scale tip down.
- ✓ When both sides are level, the masses are equal.
- ✓ Non-standard units (blocks, marbles) can be used to compare masses.