Questions: Comparing Weights: Heavier and Lighter

Question 1

A large, puffy pillow and a small, solid rock are placed on opposite sides of a balance scale. The rock's side sinks down. What does this tell you?

• A. The scale must be wrong — the bigger object should always weigh more
• B. The rock is heavier than the pillow even though the pillow is much larger
• C. The pillow is heavier because it takes up more space
• D. Both objects weigh the same since the scale only tilts a little

Answer: (B)

The side that sinks on a balance scale is the heavier side — always. Even though the pillow is much larger, the rock is denser and heavier. This directly demonstrates that size and weight are different properties: a smaller object can be heavier than a larger one. The scale is the honest referee — it responds to weight, not size.

Question 2

Without using a scale, what is the best way to compare the weights of two objects?

• A. Look at which object is bigger
• B. Look at which object has a darker color
• C. Hold one object in each hand and feel which one pulls down more on your arm
• D. Measure each object with a ruler

Answer: (C)

Weight is felt as a pulling force — the heavier object pulls more strongly on your arm. Holding one object in each hand lets you directly compare these forces. Looking at size or color tells you nothing reliable about weight; a ruler measures length, not weight. Your hands are a natural weight-sensing tool.

Question 3

A balance scale's pan that sinks lower is holding the heavier object.

• T. True
• F. False

Answer: True

Gravity pulls heavier objects down more strongly. On a balance scale, the side with the greater weight always sinks lower, and the lighter side rises. If both sides hold equal weight, the pans hang level. The key is to wait for the scale to stop moving before reading the result — a scale still in motion hasn't shown its final answer.

Question 4

A large object is generally heavier than a small object.

• T. True
• F. False

Answer: False

Size (how much space an object takes up) and weight (how strongly gravity pulls on it) are different properties. A large, fluffy stuffed animal can be lighter than a small iron bolt because they are made of very different materials. This is one of the most important early measurement lessons: different attributes tell you different things, and you need the right kind of test for each.

Question 5

A child sees a large cardboard box and a small metal bolt on a table. Without touching them, she says the box is definitely heavier because it's bigger. What mistake is she making, and how would you find out which is actually heavier?

Model answer: The child is confusing size with weight. Large objects can be very light (like a hollow cardboard box) and small objects can be very heavy (like dense metal). To find out which is actually heavier, hold one in each hand to feel which pulls down more, or place them on opposite sides of a balance scale — whichever side sinks is heavier.

Weight is a property determined by the material and density of an object, not its visible size. The reliable ways to compare weight both involve actually measuring the pull of gravity — either by feel (hands) or by instrument (balance scale). Visual appearance is misleading because it only tells you about size, not density.