Students will make reasonable estimates when measuring length and mass, as well as gain experience selecting and applying measurement tools and estimating measurements. Students will: 
- describe the difference between a reasonable estimate and a guess. 
- make reasonable estimations by using benchmarks of familiar objects. 
- estimate length using centimeters, meters, inches, feet, yards, and miles. 
- estimate an object's mass using grams, kilograms, ounces, and pounds. 
- compare estimated and actual measures to improve your estimating skills. 
- choose the right unit of measurement to accurately determine an object's length or mass. 
- practice using measurement tools to verify actual length measurements. 
- estimate an object's capacity using cups, pints, quarts, gallons, and liters. 

- What does it mean to analyze and estimate numerical quantities? 
- When is it appropriate to estimate versus calculate?
- What makes a tool and/or strategy suitable for a certain task? 
- Why does "what" we measure affect "how" we measure?
- In what ways are the mathematical attributes of objects or processes measured, calculated, and/or interpreted?
- How precise should measurements and calculations be?

- Area: The number of square units needed to cover a flat surface.
- Estimate: A rough judgment or calculation.
- Mass: The amount of matter that makes up an object. Typically measured in grams.
- Square Unit: A unit used to measure area.
- Volume: Measure of how much space is contained within, or occupied by, a
three-dimensional shape.
- Weight: The amount of gravitational force applied to an object. Typically measured in pounds.

- white paper to draw on
- rulers with inches and centimeters
- dollar bill to use for modeling (optional)
- chart paper
- meter stick or a piece of string cut to meter length
- objects of various mass (optional)
- scale (optional)
- various units of measure for capacity: measuring cup, water bottle, empty 2-liter soda bottle, empty 1-gallon milk carton (optional)
- Measurement Conversions chart (M-4-1-3_Measurement Conversions)
- I Spy Sheet (M-4-1-3_I Spy Sheet and KEY)
- Routine Example worksheet (M-4-1-3_Routine Example)
- Estimating and Measuring Length worksheet (M-4-1-3_Estimating and Measuring Length)
- Capacity (M-4-1-3_Capacity and KEY)

- Supervise students’ responses to questioning throughout the length and mass investigations to decide who may require further practice. 
- Examine students' replies to the I Spy scavenger hunt recording sheet and use questions to measure their level of mastery. 

Scaffolding, Active Engagement, and Modeling 
W: Explain to students the concept of benchmarks and their application in measurement estimations. 
H: Students should draw a six-inch line on a piece of paper. Use it as a benchmark to visually identify classroom items that are longer or shorter than six inches. Check the length of some of the items by measuring them. Consider items in the school that can best be measured with a meter stick. 
E: Consider benchmarks and estimation when calculating weight. Allow students to hold items of varied weights in order to gain a better understanding of their own weight. Compare various objects, figure out which is heavier, and weigh them if a scale is provided. 
R: Consider taking students to a location where they can explore and identify objects to estimate length or mass, creating useful benchmarks. Students are asked to complete the I Spy Sheet as they explore. 
E: Encourage students to write in a math journal about their perspectives on using benchmarks when measuring and their usefulness. Have them provide specific examples. 
T: Ask students to estimate the length or mass of a familiar item or a photograph of one. Make a list of measurements and items that best fit each measurement. Allow certain students to estimate capacity based on their understanding of length and mass. 
O: This lesson aims to help students develop estimate skills when measuring. 

"In today's lesson, we'll look at measurement in more detail and how to make estimates with measurement. Remember that when estimating, we do not choose a number at random. That'd be more like guessing. Estimating is the process of generating an answer based on information we already know. We can use benchmarks to help us. Benchmarks are standard measurements that can be used to estimate length, weight, temperature, time, and area. If I told you a dollar bill is about 6 inches long, could you use that as a benchmark to determine the length of an object? If I told you I am about 5 feet tall, can you estimate how tall the doorway is? If I told you a sheet of paper has an area of about 90 square inches, can you estimate the area of a top of a desk?”

Review the measurement skills learned in Lesson 1. Give each student a sheet of white paper, and make sure they have a ruler. Ask students to draw a 6-inch line on their paper. "The line you just drew can be used as a benchmark. It is about the same length as a dollar bill. Visualize how long 6 inches is, and then look around the room for two objects with a length under 6 inches and two objects with a length that is longer than 6 inches." Give students time to think-pair-share with their classmates. Gather student responses and record them on chart paper. Discuss the ways students used to identify objects. Ask questions similar to those listed below.

Explain how you knew if an object would be shorter than 6 inches in length. (if it looked shorter than my benchmark)
Explain how you knew if an object would be longer than 6 inches in length. (if it looked longer than my benchmark)
Is there any object on our list that you think would be approximately 12 inches in length? What are you basing your decision on?
Confirm some of students’ estimated predictions by having volunteer students measure. Discuss findings.

"Look at the meter stick. It is slightly longer than a yard. About how many meters tall is our classroom doorway? How can using this meter stick as a benchmark help us estimate?" Give students some time to think-pair-share. Then, ask students to express their predictions and thoughts. "What is our classroom's length, to the nearest meter? How can using this visual benchmark for a meter help you? Does knowing the height of our classroom doorway help you make a better estimate?" Ask students to discuss their estimates and ideas. Then, have several students measure the length of the classroom and share the results with the class. 

Ask students to develop as many different ideas as possible to finish the following stem: Some objects in our school that are longer than 1 meter are ... 

Give students about a minute to finish their task. Have students share with a partner before attempting to share one object. 

Distribute the Measurement Conversions for Length chart to students (M-4-1-3_Measurement Conversions). Explain to students that this chart shows measurement conversions that can be useful in determining length. To get students to estimate length, ask questions similar to the ones listed below. To make this a more tactile activity, label different areas of the classroom with different length measurement units. Ask students to go to that part of the classroom.

To measure the length of a humpback whale, should you use miles, feet, inches? (feet)
To measure the length of a couch, should you use centimeters, meters, miles? (meters)
To measure the length of a shoelace, should you use inches, feet, yards? (inches)
Is the width of a doorway approximately 1 yard, 2 yards, or 3 yards? (1 yard)
Is the length of a photo 6 centimeters, 6 inches, or 6 feet? (6 inches)
Is the height of your desk 1 foot, 2 feet, or 3 feet? (2 feet)

"We also can use benchmarks when we want to estimate how much an object weighs." Give each student a copy of the Measurement Conversions for Mass chart (M-4-1-3_Measurement Conversions). The purpose is not for students to memorize the conversions, but to help them build a stronger number sense when it comes to various units of measurement. To help students understand the mass of items, have many objects available for them to hold or visualize along with their corresponding mass in various units. Ask students to review the chart and make some observations and/or comparisons about mass. Encourage students to refer to any personal benchmarks they may have related to mass. One example could be how much their dog or a bag of potatoes weighs. Record student observations on chart paper.

Ask students to take out a textbook and feel its weight. Explain to students that textbooks often weigh between 1 and 2 kilograms. Show students a paperclip and explain that its mass is around 1 gram. Explain to students that an average apple weighs 4 ounces. Ask students to look around the room for two objects that they believe have roughly the same mass. If possible, have a scale available to measure the mass of each object; or students can ask another student to hold the two things and decide if their masses are similar. Ask students to look around the room for two things with extremely different masses. If possible, have a scale available to measure the mass of each object, or students might ask another student to hold the two things and determine if their masses differ. 

To get students to estimate mass, pose questions similar to the ones listed below. To make this a more tactile experience, label different parts of the classroom with different mass measuring units. Have students go to that part of the classroom. Discuss the findings and explain your thinking.
Would you weigh your bike in ounces, pounds, or tons? (pounds)
Would you weigh a fourth grader in grams, or kilograms? (kilograms)
Do you weigh airplanes in ounces, pounds, or tons? (tons) 
Would a slice of white bread weigh 1 ounce, 10 ounces, or 1 pound? (1 ounce). 
Does an average-sized basketball weigh about 2 ounces, 22 ounces, or 22 pounds? (22 ounces) 
Does a chicken egg weigh around 6 grams, 60 grams, or 6 pounds? (60 grams) 
Does an adult whale shark weigh around 20 pounds, 200 pounds, or 20 tons? (20 tons)
"Estimating the mass of an object requires practice. Benchmarks may help you generate a point of reference for more accurate estimations." 

"Let's go on a scavenger hunt looking for objects for which we can estimate length or mass." Choose a location or area that students may explore, such as the library or the outdoors. If this is not an option, students may imagine a supermarket or home improvement store. (Using sales fliers for these stores is another option, as the visual prompt may help students better grasp which goods to select.) Remember to keep benchmarks in mind. "Please bring the Measurement Conversions for Length or Mass charts with you just in case you need it."

Give students copies of the I Spy Sheet (M-4-1-3_I Spy Sheet with KEY). The purpose of this task is not always to complete the full chart. Rather, the idea is to experiment with measuring in a creative way while also looking at the surroundings to create measurement benchmarks. While students are working on their charts, ask questions like the ones listed below. 

Explain how benchmarks can help you estimate measurements. (They provide a visual reference.)
What's one benchmark you use to estimate length? (a ruler, meter stick, etc.)
What's one benchmark you use to estimate mass? (textbook, hand weight, etc.)
When is it useful to be able to estimate measurements? Why? (It is useful to estimate measurement when we have an accurate benchmark to work with and do not need to be precise. We may estimate since it is faster or when we lack the tools needed to measure precisely.) 
When is it appropriate to use an estimated measurement? (When we simply need to know how many rather than exactly how many, for example, when deciding clothing sizes, fabric lengths, the number of rolls of tape required, etc.) 
When is it necessary to take an actual measurement? Why? (When we need to know exactly how many for proper fit or safety reasons, for example, when following recipes, building construction, spending money, etc.)
What unit of measure do you think is the most difficult for you to find an example of? 
What unit of measurement can you provide many examples of? 
What object can you find that has a length greater than 1 meter? 
What object could you find that weighs less than 10 pounds? 
Use the replies from the previous part of the lesson to assess student understanding. Students should complete the following journal response.

How can using benchmarks help you make reasonable predictions for length and mass? Explain your thinking with a few specific benchmarks. 
"In the lesson today, we focused on estimating measurements. When we estimate measures, we want to make sure that they are reasonable. Sometimes we need an exact measurement, such as when buying a new sink to replace an old one. Other examples, we can utilize an estimated measurement, such as determining how many miles a road trip will be."

Extension: 

Use the following strategies and activities to meet the needs of your students during the lesson and throughout the year.

Routine: Show students an object or a photo of an object. Tell students whatever attribute you want them to estimate. Then offer students two or three options for an estimated measure. In their math journal, have them record the object, the estimated measurement, and a brief explanation of their reasoning. Distribute copies of the Routine Example Worksheet (M-4-1-3_Routine Example). Students will become more proficient at estimating measurements using various units of measure as they gain more practice and experience.

Small Group/Technology Connection:
Option 1: In their math journals, have students draw a chart for length and mass similar to those seen below. As a group, list as many different items/objects as possible that can be measured using the chart's units of measurement. Share the items in the chart with students to help them develop a visual benchmark for each unit of measurement. Create scenarios for students to consider and answer based on the items listed in the charts, such as those listed below. 
Is a dog's weight greater or less than two kilograms? (usually more) 
Is a backpack heavier or lighter than ten pounds? (answers will vary)
Is the chalkboard larger or less than one yard in length? (answers will vary)
Is the length of the school building more or less than a mile? (less)



Option 2: Students who require further help with mass may find the following website useful: http://www.studyzone.org/testprep/math4/d/massgram4p.cfm. The website invites students to sort things by mass and select those that can be measured in grams. Immediate feedback is given. To review estimating length, the following link contains a PDF worksheet that students can complete in small groups. http://www.education.com/files/55101_55200/55172/file_55172.pdf. Encourage students to share their explanations and the benchmarks they used to guide them. Students can practice estimating and measuring with a ruler to the nearest ¼ inch or centimeter by filling out the Estimating and Measuring worksheet (M-4-1-3_Estimating and Measuring Length).

Expansion/Technology Connection: Students who demonstrate proficiency in grasping the concepts of length and mass may be asked to investigate the concept of capacity. Explain to students that capacity is the quantity that a container can hold. Students can learn about capacity by visiting the Cyberchase: Can You Fill It? website. http://pbskids.org/cyberchase/find-it/measurement/. Students can estimate how many pots are required to fill a specific container. Then, students can test their predictions by completing the activity. This activity will help students gain a better visual spatial sense of capacity. Students can build a Gallon Man model to better grasp the relationship between cups, pints, quarts, and gallons. Provide students with a variety of capacity units (e.g. measuring cup, bottle of water, empty 2-liter soda bottle, empty 1-gallon milk carton) to help them understand the relationship between unit of measure and amount. Students can investigate the relationships between the various units and fill out the Capacity worksheet (M-4-1-3_Capacity and KEY) to estimate the approximate capacity of the provided objects.
This lesson aims to provide students practice utilizing estimate skills when measuring. Students will know the difference between guessing and estimating. Estimation is the use of known knowledge rather than guessing at random. Using benchmarks allows students to generate more reasonable estimates. Students will learn about numerous length units (inch, foot, yard, mile, centimeter, meter) as well as mass units (ounce, pound, gram, kilogram). Students will be presented conversions not to memorize, but to gain a sense of mass so that they can make more reasonable and accurate estimates. When students estimate measurements, they will use everyday objects and/or pictures.