Part of Unit: Measuring
Lesson Plan Overview / Details
Students will learn how an inch is broken in to fractional units by creating an oversized paper inch.
- full lecture, demo, activity
- 55 Minutes
California Career and Technical Education Standards
California Academic Content Standards (Reinforced)
Objectives and Goals
Students will accurately read measurements on a customary ruler. Students will understand that the customary system shows yards, feet, inches and fractions of an inch and that this system is mostly used in the construction industry here in the USA.
Activities in this Lesson
- Win this bar! (illustrated ruler without numbers) - Hooks / Set
Students will pick up the pre test handout on measurement (see below) as they walk into the class room. For their daily writing activity, they will take the pre test. After taking roll, students will see an illustration of a ruler on the white board with several fractional marks labeled A, B, C, etc. with a candy bar taped on the board next to the words “Win this bar!” There are no numbers on the ruler illustration so the units of measure are not yet known. Ask students to raise their hand if they can name the fraction mark for A, B, or C. This is a trick question as all answers are right or wrong since we have not establish the fractional divisions (no numbers are on the board so we don’t yet know how many units the inch is broken down into). The first student that figures out that you need to know what the graduated units are will win the candy bar.
- Lecture, Demo, Activity combined - Lecture
Pass out a small piece of paper (about 2 inches by 8 and1/2 inches) and have students write their name on one side. Ask the students to fold the piece of paper in half. Have them unfold and mark the halfway point by drawing a line halfway down the crease (see example) and marking it 1/2. Tell the students that we are going to pretend that this is an inch. Show them an example of what you want by drawing it on the white board. They should mark the left side of the paper 0 and the right side 1.
Ask them to fold the paper at the halfway point again and then fold it in half again. This will locate the ¼ inch marks. This time they should draw lines in the creases half as long as the ½ mark line (the last line they made) and mark them as ¼ and ¾. Again draw an example on the white board. I sometimes mark the ¾ mark as 2/4 and ask the students if this looks correct to them. Then we can talk about why this is both correct and incorrect. Explain that the ½ mark is also 2/4 but we call it ½ because it can be reduced. I ask the students at this point to tell me how many “parts” or “sections” there are to the inch we are making. Show them there are now four parts to our oversized inch. This is why we call each mark a quarter (1/4). Relate that to a dollar by asking how many quarters are in a dollar. Now ask how many ¼ marks make up an inch (4/4 = 1).
Have students fold and continue to fold and mark their oversized inch to 1/8 and then to 1/16 units shortening the line lengths and numbering the lines at each division. I show them how we are measuring by dividing the whole into sections - first 2 then 4 and so on (8,16 etc.). Ask them what they notice about the numerator (the number on top of the fraction). They should note that the number is always odd. Ask them what they notice about the denominator (the number on the bottom of the fraction). They should note that the denominator is always even. Remind them that if the top number is even it can be reduce 2/8 = ¼, 2/16 = 1/8, etc. In the fractional measuring system we always reduce to simplest terms.
Explain that the length of each line at each new fold is half as long as the last division and that this will help them determine what unit of measure they are looking at because fractional numbers are not found on a standard ruler. The length of the line will help determine the fraction. Longer lines represent larger fractions and shorter lines represent smaller fractions. count the units of division. When trying to figure out what a given fraction on a ruler may be, I tell students to start at the mark in question and count every line that is as long or longer back to the first whole number i.e. at the 3/4 mark you would start at 3/4 and count, 1/2, 1/4, 0 = three divisions making the top number of your fraction 3 and then count forward to the first whole number i.e. 3/4 to 1 = 1. Add the two numbers 3 and 1 and you get 4. 4 that is your bottom number. You get 3/4.
Lecture: There are 36 inches in a yard and 12 inches in a foot. Corresponding units of area and volume are the square inch and the cubic inch. The inch is one of the most common units of length in the United States, and is also widely used in the United Kingdom, and Canada, despite the introduction of metric to the latter two in the 1960s and 1970s, respectively. The inch is sometimes used informally in other Commonwealth nations, such as Australia.
- Assessment Types:
- Teacher-Made Test,
Hand out the post test (same as the pre-test): Don’t forget to remind students about writting down and included the whole numbers once you go past the inch marks i.e. 2 and ¼ inches, 3 and 1/8 inches etc..
- measuring test and pre-trest [ Download ]