I begin today by holding up a series of objects of different shapes and sizes. I ask, "How can I measure this?" and I ask students to write in their math journals the ways they might measure the object.
I hold up a ball, a cup of water (saying I want to measure the water), a curved seashell, a bottle of paint and a stuffed bear.
Once students have recorded how they might measure the object, either in words or pictures, I invite them to share their ideas. I ask students to demonstrate as they share their ideas.
I show students several containers for water. I label the containers from A to F. Now I ask them to put the containers in order from least to greatest amount they will hold. I tell them that we will think about how we measure water as we check our predictions. Students must decide on the order and then be able to explain why they picked the order they did (construct viable arguments and critique the arguments of others MP3).
Once all the students have written out their predictions, I make a table on the Smart Board and we record everyone's order. We tally to see which containers most people think hold the least, next least, etc. We line them up in order based on the tally. Next I fill the smallest voted container with water. I try to pour all that water into the next container. If it fits and there is more space, I add more and we agree that the first container was the smaller than the second one. If it overflows, we know that wasn't the smallest and we have to look for another one and repeat the process. We repeat the process until we have the containers in order.
Now I discuss the terms ounces and liters. This is another way to measure water. I pour the water from the smallest container into my measuring cup and ask students to read the amount in cups and ounces. Now I pour water from the next smallest container and repeat the process. I do this to reinforce that we can measure in many ways other than inches and centimeters.
I explain that when we measure how much of a liquid, we are measuring the volume or how much something will hold.
I ask students to take out their Strategies Books. These are books we created in another lesson. They have ideas for different strategies that the students use to solve different types of math problems. I ask the students to write down 3 tools they could measure something with, the unit it measures in such as inches or ounces if they know, and examples of something they would measure using that tool.
I can use the book entries as an informal assessment of their understanding of the various types of measurement.