For this warm up I present this problem to students to solve on their whiteboards:
Tony cut a five meter ball of string into four equal sized lengths. How many centimeters long was each length of string?
After about 5 minutes, I ask student volunteers to share their answers and HOW they solved this problem, emphasizing the strategy.
You can hear and see a student explaining his strategy for this warm up problem below.
You can hear and see in this video below another student explaining her thinking. Notice my questioning technique in this video in order to help students make connections between strategies. While this isn't the greatest video because my students were somewhat quiet, this is a strategy I like. You can also see my students quickly realized the strategies were similar because they both involved division, but then had a difficult time coming up with other similarities. I then switched and asked students how the strategies were different. The video cuts off, but students did have more to say about how they were different.
My students have had prior experience with measuring capacity in both the metric and customary systems in science lessons and labs. My students are also familiar with using liquid measuring tools (e.g. graduated cylinders).
I begin this lesson by reviewing the terms milliliter and liter. I ask students how they can determine what a milliliter is if they forget. (Students respond with that they know milli means 1/1000. I also review with students that milliliter can be abbreviated as mL or ml.
Then I review how to use a function or input/output table as a tool to help with conversions. This is a skill that some students understand while others are struggling, therefore, I need to make sure to continue to review this strategy for all students.
Next, I tell students that they will be making Horrendous Soup today. I then display the start page to the Horrendous soup game. http://mrnussbaum.com/soup-play
I read this scenario (quite dramatically) to students.
Have you ever made soup before? If so, I bet you've NEVER made Horrendous Soup. Now's your chance to bring justice to all who have forced you to eat food you hate. To make Horrendous Soup, your job is to make the most disgusting brew in the history of EARTH! Simply add ingredients from three categories: mass, distance, and capacity. To prove to the world that you have made the most terrible concoction the world has ever seen and tasted, you have to get the recipe right. To get the recipe right, you have to show the ability to CONVERT the mass, capacity, and distance of the given ingredients to different metric measurements. For example, if the recipe calls for 3 liters of baby food, you might have to convert it to 3000 milliliters. If it calls for 200 milligrams of toothpaste, you might covert it to 0.2 grams. Finally, if the recipe calls for 2 meters of celery, you might have to convert it to 200 centimeters of celery and 2,000 millimeters of celery!
Then, I take turns drawing students names from my stick cup for students to come to the smart board and choose ingredients for the soup. As ingredients are added, I keep track on the board and students keep track in their notebooks. You can see an example of this in the photo below.
Notice in the photo that students aren't necessarily converting from larger to smaller units for this task, so I do end up helping them and walking through some of the conversions together.
Once all ingredients have been chosen and added to the soup, students finish the conversions in their notebook using the table they created. I give students about 6 minutes to fill in the missing numbers and then we talk about the conversions together. Since this game doesn't have students only convert from larger to smaller units, (as called for in the standard) but also from smaller to larger, the conversation and discussion is an important component of this lesson. Many students are able to see the connections between moving from smaller to larger units, and visa versa, while others need scaffolds and prompts to guide their understanding.
(Note: the decimal numbers in this game were also a great way for students to review reading and writing decimal correctly as well as a built in differentiated experience for my students needing a challenge.