Ordering Three Objects from Shortest to Longest
About this lesson
In this 40-minute kindergarten lesson, children work in small groups to line up pencils, crayons, glue sticks and other everyday objects along a shared starting edge. They order three of the objects from shortest to longest and draw what they found. They learn why the ends must match before comparing. You need a basket of classroom objects per group, paper, crayons and tape.
- Grade
- Kindergarten
- Subject
- Math
- Time
- 40 min
Objective
Students will compare the lengths of three classroom objects by aligning their ends and arrange them in order from shortest to longest, explaining their order using the words shorter, longer, shortest and longest.
Materials
- One small basket or tray per group with 5-6 classroom objects of clearly different lengths (new pencil, short crayon, glue stick, marker, eraser, paintbrush)
- Masking tape to make a starting line on each group's table
- Plain paper (one sheet per group)
- Crayons
- Chart paper and a marker for the class anchor chart
Hook
Hold up two pencils of different lengths, but place the shorter pencil higher in your hand so its top sticks up past the longer one, and ask, 'Which pencil is longer?' Let a few children answer, then lay both pencils flat on a table with their ends touching a strip of tape and ask the class to look again. Talk about how the shorter pencil only looked longer because it was not starting in the same place.
Main Activity
Before groups start, put a strip of masking tape across each table to be the starting line, and model on the chart paper how to set objects down so one end touches the tape. Place children in groups of three and give each child a job: the Placer puts objects on the starting line, the Checker makes sure every end touches the tape, and the Recorder draws the final order. Each group chooses any three objects from its basket, lines them up together, and agrees on the order from shortest to longest. When the group agrees, the Recorder draws the three objects in order on the paper, and the group says aloud, 'The ___ is the shortest and the ___ is the longest.' Groups then switch jobs, choose three different objects from the basket, and repeat so every child has each job once. Walk around the room asking groups to show you how they know their objects are in the right order, and add a few groups' examples to the class anchor chart.
Discussion Questions
- Why did your group put all the objects on the tape line before deciding which was longest?
- What did your group do when you did not agree about the order?
- Can an object be the longest in one group of three and the shortest in another group of three? How?
- How could you find out which is longer if two objects look almost the same length?
Exit Ticket
Give each child a pencil, a crayon and a glue stick (or any three objects of different lengths). Ask the child to line them up at the edge of the table and point to the shortest and then to the longest, saying each word aloud. Note who aligns the ends without being reminded.
Differentiation
Support: Start struggling learners with only two objects that differ greatly in length, such as a crayon and a ruler, and have them use only the words longer and shorter. Tape a green dot on the starting line so they know where the ends go. Once they succeed, add a third object that is clearly between the first two in length.
Extension: Challenge advanced learners to order all five or six objects in their basket from shortest to longest, or to find an object somewhere in the classroom that fits between two objects already in their line. They can also cut a paper strip that is longer than their longest object and shorter than a table side, then explain how they checked.
