You have a tall, thin cup and a short, wide bowl. A student says the tall cup must hold more because it looks bigger. What is the best way to find out which actually holds more?
AMeasure the height of each container with a ruler
BWeigh each container on a scale
CFill one container with water and pour it into the other to see if it fits, spills, or leaves empty space
DCount the number of colors on each container
Capacity is about how much fits inside a container — and that cannot be reliably judged from height or width alone. A tall, thin container may actually hold less than a short, wide one. The fill-and-pour method directly tests capacity: if the water fits exactly, capacities are equal; if it spills, the first held more; if there's space left, the second holds more.
Question 2 Multiple Choice
Which of the following is a capacity question?
AHow tall is this water bottle?
BHow heavy is this bucket when it's full?
CHow much juice can this pitcher hold?
DWhat shape is this container?
Capacity describes how much a container can hold — the space inside it. Height, weight, and shape are related attributes but they are not capacity. 'How much can it hold?' is the defining capacity question, and the answer always refers to the amount that fits inside.
Question 3 True / False
A tall container usually holds more than a short container.
TTrue
FFalse
Answer: False
A tall, thin container can hold less than a short, wide one. Capacity depends on the size of the inside space in all three dimensions, not just height. This is why looking at containers is unreliable — you have to fill and pour to find out which holds more.
Question 4 True / False
To compare the capacity of two containers, you can fill one with water and pour it into the other.
TTrue
FFalse
Answer: True
This is the core method for comparing capacity without formal units. If the water fills the second container exactly, they hold the same amount. If it overflows, the first holds more. If space remains, the second holds more. The fill-and-pour method directly tests the inside space of each container.
Question 5 Short Answer
In your own words, explain what capacity means and how you would find out which of two differently-shaped containers holds more.
Think about your answer, then reveal below.
Model answer: Capacity is how much a container can hold — the amount of space inside it. To compare two containers, fill one with water (or use a scoop to count how many scoopfuls fill it) and then pour that into the other container. If the water overflows, the first container held more. If there is space left over, the second container holds more. If it fits exactly, they hold the same amount.
The key idea is that capacity is an interior property that can't be judged by shape or height alone. The fill-and-pour method works because it directly measures and compares the interior volumes using an equal amount of liquid as the reference.