Tiles and Cubes and Clips, Oh My!
Lesson 1 of 8
Objective: SWBAT measure lengths using a variety of units. SWBAT measure accurately.
I want to continue to introduce coin names and the ability for students to identify coins out of a collection of them. I will introduce a money unit (focusing on counting and trading coins) later in June and this foundational work will help with the success of that unit.
Using the document camera, I display 2 pennies, i nickel, 1 diem, and a quarter. I ask them to tell me what coins they see. I then ask how many of each and for students to come up and point to a coin that I ask for.
"Take a look at the coins. How many pennies are there? How many dimes are their? What is this coin called (point to a nickel)? What is this coin (point to a quarter)? Who can point to the pennies?"
I then repeater the procedure with two of each coin being displayed.
"During our last lesson, we talked about measuring ht longest part of an object. We used connecting cubes to measure different objects. I want to review how to me sure an object "accurately." However, today we are going to use 1 inch tiles. Where should I start to measure? Where should I measure to (again looking for the idea of edge to edge)?"
I then start measuring with the tiles. I model using a straight line and talk about why this is important. There is a video in the resource section that models this part of the lesson.
By modeling the appropriate way to use tiles, "students are making sound decisions about why this tool might be helpful, recognizing both the insight to be gained and their limitations (CCSS.Math.Practice.MP5)"
Most likely what ever object you choose to measure will fall between two whole numbers. You should lead a discussion about who to record a length that is between two whole numbers. Terms like: "a little greater than, a little less than, or between __ & __" can be used. I also teach students who to record the fraction 1/2. Although this is not expected to be mastered at this point, it is good to start introducing this concept.
"Today you are going to use three different types of objects to measure. You can choose tiles, cubes or paper clips. You will work with a partner and find objects from around the room to measure. The only rule is the object can't be longer than your arm (This way students don't spend their whole time measuring a really long object). You will have to use the recording sheet that I am providing (section resource). In the first column, you will write the name of the object that you are measuring. In the 2nd column, you will write how long it is, and in the third column, you will circle which unit you used to measure. If the length fall between different numbers, you will have to decide how to record it by using some of the terms we just talked about (see previous section)."
It is expected that 1st grade students can "express the length of an object as a whole number of length units, by laying multiple copies of a shorter object (the length unit) end to end; understand that the length measurement of an object is the number of same-size length units that span it with no gaps or overlaps. Limit to contexts where the object being measured is spanned by a whole number of length units with no gaps or overlaps (CCSS.Math.Content.1.MD.A.2)." This activity give the students an opportunity to not only explore this concept but to also solidify their understanding of the concepts.
As the students are working, you should circulate and make sure that students are:
- measuring by starting at the beginning of the object finish at the end of the object?
- are they counting and recording the number of units used to measure accurately?
- do they double check their measurement?
*You also want to guide students with recording measurements that are between two numbers.
I have included a video clip of a group that chose to measure the same object with two different units. Although I didn't necessarily want this, I let them do it because it will benefit the wrap uo discussion at the end of the lesson.
Lesson Wrap Up
The goal of this conversation is that students understand that the measurement of a specific object, with the same unit, should be the same; even when it is measured by two different people. I also want students to understand that measuring an object using different length units will result in different measurements.
"Let's start with the tissue box again. I will use paper clips to measure it and then I will ask someone else to measure it too. If we both use paperclips, what can you say about our final measurements? That's right, they should be the same. Before we start measuring, let's review all of the things we need to do:
- measure from edge to edge
- no spaces between measuring units
- the measuring units should be in a straight line"
I then measure the box and have another student do it as well. I am explicit in following the above steps to reinforce the concept. We then talk about our final results and why the measurements were the same.
"As you were measuring today, I noticed two students measuring the same object but with two different units.. One student was measuring a tissue box with tiles and the other was using paper clips. Emma how many paper clips long was the tissue box? Cheyenne, how many tiles long was the box? I noticed that they did all of the things that we said good measuring should have. They each started at one end and measured to the other end of the object. Their units were all in a straight line and they had no spaces between the measuring units. Why did they get two different answers? I take a few responses."
Ultimately, I want the students to provide the understanding that the different size units will provide different results. I have provided a video of this discussion. The first girls has the right idea, the 2nd child who answers states something that is relevant to the discussion and the third child summarizes the discussion and understanding in beautiful way. It was great for them to listen to each other's rationales and ideas and then come up with a student led conclusion. It is expected that 1st grade math students try to "communicate precisely to others. They try to use clear definitions in discussion with others and in their own reasoning (CCSS.Math.Practice.MP6)."
I finish the lesson with a connection to the doubles facts that we have been working on. I want the students to see who they can use their knowledge of doubles facts to solve facts known as Doubles +/- 1.
Let's review some of our doubles facts. I will say a fact out loud and I would like you to whisper shout the answer back. I then call out a few doubles facts. Now I want to show you how you can use your Doubles Facts Knowledge to solve other facts.
I then write a fact on the board and show them the Doubles +1 or -1 connection. There is a photo, in the resource section, that demonstrates this work.
For those who are ready, I will move them to flash cards that focus on these +1/-1 facts. These are flashcards that I send home for practice and use in class for those "in between" times. You can make them up on index cards.