In this activity, students explore the volume of containers by estimating and comparing them. Students use a unit container to fill two containers, A and B, to determine which container can be completely filled with a greater volume of water.

To make the comparison interesting, Containers A and B should be different in size and shape, but have a similar capacity. Consider, for example, a bowl and a cup. The unit container should be small enough so that multiple iterations are needed to fill and compare Containers A and B. Consider a large spoon or a small measuring cup.

To involve every student in the measuring process, consider assigning roles of "quien llena" // “filler” and "quien registra" // “recorder” for Container A, then switch roles for Container B.

The purpose of an Estimation Exploration is to practice the skill of estimating a reasonable answer based on experience and known information. It gives students a low-stakes opportunity to share a mathematical claim and the thinking behind it (MP3). Asking oneself “Does this make sense?” is a component of making sense of problems (MP1). Making an estimate or a range of reasonable answers with incomplete information is a part of modeling with mathematics (MP4).

• “Piensen en el recipiente que se usa como unidad. ¿Cómo nos ayudó este a comparar los volúmenes de agua que se necesitan para llenar cada uno de los dos recipientes?” // “How did the unit container help us compare the volume of water it took to fill both of the containers?” (We can count how many units it took to fill each container. Then we compared them.)
• “Vimos que el volumen de un recipiente es la cantidad de líquido que se necesita para llenar el recipiente por completo” // “We saw that the volume of a container is the amount of liquid it takes to completely fill a container.”
• “Podemos decir que el volumen del recipiente A es ___ unidades porque se necesitan ___ unidades de agua para llenarlo” // “We can say that the volume of Container A is ___ units because it takes __ units of water to fill it up.”
• “Podemos decir que el volumen del recipiente B es ___ unidades porque se necesitan ___ unidades de agua para llenarlo” // “We can say that the volume of Container B is __ units because it takes __ units of water to fill it up.”

The purpose of this activity is to introduce students to liters as a formal unit to measure liquid volume. Students learn how much space a liter of liquid fills up. Then the whole class fills a large clear container with water one liter at a time. As the container is filled, students mark the container with a dry-erase marker to show the number of liters in the container.

While it is highly recommended that the class has the experience of filling and marking the container, a video has been provided to show the process and could be used for a class demonstration. Having more than one 1-liter container or some prefilled 1-liter containers will make the process of filling and marking the container go faster.

• “¿Qué números pondríamos en cada marca para mostrar el número de litros que le corresponde?” // “How would we label the marks to show the number of liters each mark shows?” (We would label the bottom mark with 1, then the one above it with 2, and keep labeling up to the top mark. The bottom of the container would be 0 liters.)
• Label the marks with numbers.
• “¿En qué se parece el fondo del recipiente al borde de una regla?” // “How is the bottom of the container like the edge of a ruler?” (They both show zero. The bottom of the container is like the 0 mark on a ruler.)
• “La palabra ‘litro’ se puede simbolizar con una L mayúscula. Podemos mostrar que cada número representa un número de litros escribiendo una L mayúscula al lado de cada número” // “Liters can be abbreviated with an uppercase L. We could show that each number represents a number of liters by writing an uppercase L next to each number.”
• Write “L” next to each number on the container that was marked and labeled.
• “Podemos decir que el volumen de agua en el recipiente es __ litros” // “We can say that the volume of the water in the container is __ liters.”
• “También podemos decir que el volumen del recipiente es alrededor de __ litros” // “We can also say the volume of the container is about __ liters.”
• “ ¿Qué otros recipientes que han visto antes tienen también un volumen de alrededor de __ litros?” // “What are some other containers you’ve seen that also have a volume of about __ liters?” (a large sink, a storage bin, a large jug of water, a bucket, a small trash can)