# Conversion Quiz: This One, Not That One! Writing About Our Choices

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## Objective

SWBAT show understanding of relative units of measurement through writing.

#### Big Idea

Students show their understanding of relative size through a writing assessment .

## Warm Up: What's My Unit

10 minutes

Materials: Small Slips of paper with examples of different objects that can be measured in metric units either written or drawn on them.(Or cut out pictures of objects from magazines.) Use objects that would represent various units of meters, grams and liters. I used things like water bottle, swimming pool, bag of candy, vitamins, the length of a window, etc.

To set the stage for today's quiz, I wanted them to think about relative units of metric measurement and to get their minds open to real life situations.

We went around the room starting with one person drawing a slip of paper out of a container and reading the slip of paper. When they answered, they were to choose a buddy to agree or disagree with their answer.

The first to be drawn out was "water bottle". The student looked at me and said "Liters". She chose a buddy and the buddy disagreed by saying " Milliliters".  I asked the class who they thought was right. A student raised his hand and said they both could be right because it depended on the size of the water bottle. I interjected and said, what do we usually see on the label of a water bottle. They didn't know. So, I told them they needed to look at containers and make themselves aware of how those containers are measured. This is an example exercising Math Practice Standard 3, critiquing others. It also is part of Math Practice Standard 4 because the water bottle is a real life model of mathematics.

We continued with this game and discussed the possibilities of each answer for each word they chose. I kept the game going by facilitating the discussion with questions that revolved around each example. Some answers were very straightforward and the pace picked up as they warmed up.

## The Quiz

30 minutes

Resource: Conversion- Choosing the Unit and Why.

Rubric for Writing About Relative Sizes

Rationale: As I prepare students for state CCSS assessments, I keep in mind that in those assessments students will be expected to write about their thinking. So, as I transition and develop tests and quizzes, I always include assessments that tell me about their thinking. This serves two purposes: 1. It reminds them that they will be held accountable for their thinking and have to explain to master the standard fully. 2. It gives me a clearer picture of their understanding and then I can use that data to decide what standard is mastered and to what degree, since many standards are multi-faceted.

This quiz will tell me if they can decide the correct unit of measurement for objects and if they can properly convert to a smaller unit. I told them to try and pick 2 of the 3 objects in a unit that was not in the milli unit category. They used their flip books from past measurement lessons. Flip Books are Fun! shows students with their gram flipbooks.  If students did not make flipbooks, they could collect pictures or write a list of items (water bottle, a sky scraper, the distance from home to school, a bag of dog food....etc.) to sort prior to the assessment.

After students got out their flip books, I passed out the quiz and read directions to them, carefully explaining and drawing an example of the chart on the board. I encouraged them to use the stair step model and equations to figure out their conversions.