In this lesson, we'll learn how measuring with nonstandard units can prepare students to understand conversions once they begin using standard units of measure.
It's time to begin your unit on measurement. Before you get started, though, there are some considerations to make. You will have to think about all the different measuring concepts, including length, weight, mass, volume, temperature, distance, money, and time. You also have to think about the U.S. customary standard of measure, which is used in the United States, and the metric system, which is used in other countries and the scientific community.
It's your job to figure out how to cover all these topics while also giving students a basic understanding of how to use measurement tools and make comparisons. It seems you have your work cut out for you.
Let's take a look at some of these concepts and how you can teach them in your classroom.
Nonstandard Units of Measure
Before introducing standard measurement tools , such as a ruler or a scale, students should understand the basic concepts of measurement using nonstandard measurement tools, which are things that are not intended to be used for measurement, such as the student's thumb, blocks, or erasers. Rudimentary principles of measure, such as comparing lengths and weights, have more meaning to students when they use objects that are readily available to them to make the measurements.
Once students comprehend using nonstandard measurement tools, they will be able to perform conversions. Conversions are changes to the form of measurement. For example, a student might measure the length of a book using a crayon. Then he would measure the length of the book using his foot. Will he need more crayons or more feet to measure the desk? How many crayons equals a foot? This line of thinking will naturally lead to the student being able to move easily between the different standard units of measure.
Standard Units of Measure
What are some standard units of measure that students need to learn? In the U.S., most people use customary units of measure, such as feet or pounds. Students need to be familiar with these, but metric units, such as meters and grams, are more commonly used in the rest of the world, in higher education, and by those who work in various fields of science. Regardless of the unit used, students should also know how to use measurement tools, such as a tape measure or a ruler.
Prior knowledge about length and weight can be activated by discussing trips to the doctor's office. Questions regarding why the doctor takes measurements can stimulate thinking about absolutes in measurement, as well as changes that might occur over time. Activities in which they measure parts of their own bodies are engaging to students and lead to further exploration.
Scales are used to measure mass and weight in kilograms and pounds. Students can use balance scales to find standard measures by placing a standard mass on one side of the balance while measuring how many pennies, paperclips, or other objects it takes on the other side of the scale to create balance. Students can create their own balance scales using hangers with cups suspended from strings on either side.
Another measure that students should be taught is elapsed time, which is how long it takes for something to happen. Stopwatches, timers, and clocks are used to measure time. One way that teachers can support student understanding of time is through consistent use of timers throughout the day. For example, if Miss Ward says students have ten minutes to complete an assignment, she should use a timer and stick to that ten minute time limit.
Once students have a firm concept of how to measure one-dimensional objects and of different units of measure, their knowledge may be expanded to the measurement of two and three dimensional objects:
- The surface of a two-dimensional object is the area. The area of an object is the length times the width and is measured in square units.
- The perimeter is the distance around an object. It's determined by adding the length of all sides.
Unit cubes, geoboards, and grid paper are tools that teachers can use to help students develop a conceptual understanding of area and perimeter while inspiring engagement and creative thinking. This type of measurement supports the incorporation of hands-on, real world problem solving, which may include tiling, carpet laying, or creating floor plans.
When students first begin to learn about measurement and conversions, they will use nonstandard units of measure. Nonstandard measurement tools are things that are not generally considered measurement devices but are used for measurement to help students understand basic measurement concepts and prepare them to comprehend conversions. Conversions are changes from one unit of measure to another. Anything of consistent size that's readily available can be used as a nonstandard unit of measure.
As the student's conceptual understanding of measurement grows, students should be introduced to standard units of measure. Standard units of measure can be U.S. customary units or from the metric system. Students who have background knowledge measuring height and weight can expand their understanding of standard units of measure.
Measurement tools such as rulers, scales, and stopwatches are used by students to experiment with measurement. Measurement activities that are relevant and exploratory in nature have the most meaning for students.