Lesson Plan Industry Sector
Transportation

## **Measurements and Mathematics (updated) By Michael Drouin

### Lesson Plan Overview / Details

In this lesson, students will be introduced to measurement and measurement tools.

Classroom/Lab
1 Day

### Student Objectives / Goals

• Student will construct a visual aid that will help them make measurements down to 1/16".
• Students will demonstrate the ability to read standard ruler.

### Activities in this Lesson

• I use this to start down the road to precision measurement. I talk about how we will need to be able to take measurements that will be one third the size of a hair (usually get a laugh as I point to my some what balding head).

Then I show them some of the instruments we use. I show then a micrometer, dial caliper, and a dial indicator, and then I pull out a 6"steel ruler from my top pocket. I tell them that you will probably find one in most technician's tool boxes and it is still of some use.

If you were at a junk yard and wanted a Chevy 350 small block, I can use it to separate the 350's from the 305's and 307's that nobody wants. I walk to a couple of blocks (position prior to the class) and, using the ruler, I check the bore. "This one is 3 7/8"-- no good. This one is 3 7/8"-- no good."  I make sure that the students can clearly see me lay the ruler across the bore and take the reading. Then I come to the one that measures 4", this is the one I want. I tell students that when we get done today, they will be able to make simple measurements down to 1/16th of an inch.

• Hamburgers to Hot Dogs - Demo / Modeling

I tell students, "We are going to make a visual aid that will help you understand what each of the tick marks on the ruler mean."

I put an overhead up of a section of a ruler, then hand each student a blank piece of paper. I say, "Take your piece of paper and hold it up, hamburger way, not hot dog way (wide across the top).  Now take the two corners bring then together then with one swift movement crease the center line. Before opening it, I ask What have we done? Let them answer a bit, then tell them we have divided the one into two and unfold the paper. Show them the two sections. Now take your pencil draw a line 2/3 the way down the creased line. Now label it as one is now two. I draw a picture of the paper on the board, draw the creased line down the middle and label it 1/2.

• Fourths/quarters - Demo / Modeling

Next we fold the paper again (fold it back in half) then fold it once more. Before opening it, ask how many sections the paper going to be in. Someone will answer four. Open the paper, show it is in four sections. Go to the creased folds and draw two shorter lines(than the 1/2 line) on the scale. Have students draw on there paper. Label them as 1/4 and 3/4. I point out that it is one of four, two of four (which is 1/2) and three of four.

• Reading a ruler - Group Work

Continue doing this dividing the paper, drawing shorter lines, and label the fraction for the 1/8 and 1/16.  Make sure you do it on your drawing on the board.

I then explain that to read a ruler you first determine how many complete one inch increments there are. Then count the number of tick marks past the last complete inch. Then look at the visual aid you just made. Count the number of tick marks from the left. That gives you the fraction.

I tell them that I know that most feel pretty comfortable just reading the fraction direct (most do not) but for the first few problems on the work sheet please count the tick marks.

• Then I hand out the work sheet. I also have the first couple on the overhead to guide them through the first couple of problems. I ask them, how many complete inches do you see? O.K., how many tick marks? Some one will say seven (or what ever the answer is) then I go to the board and count seven tick marks on my visual aid and come up with the fraction. Do a couple then you really have to walk around and check each students work most really struggle and will need help. At the conclusion of this session we will review all of the information to see how much they have retained. I will then let the students know that we will continue this discussion and review the material until they understand it.