Iowa DOT's policy is to be
sensitive to the environment
and foster and enhance
environmental stewardship.

IOWA DEPARTMENT OF TRANSPORTATION

Presents

ROCKS AND ROADS

Unit 4: How are highways designed?

I. Activities

Centrifugal Force-Go-Round Activity

Draw the Viewpoints Worksheet

What are interchanges? Worksheet

What is a drawing scale? Worksheet

Why is a drawing scale used? Worksheet

Centrifugal Force-Go-Round

Introduction - This activity will give students the opportunity for hands-on activity to apply the following centrifugal force information covered in Unit 4:

"Horizontal curves, and vertical curves to some extent, are controlled by traffic speed. If the curve is too tight, vehicles will have the tendency to skid off the road when they travel the curve. This is due to centrifugal force."

Materials Needed - Electric race car and track set

Directions - The teacher can discuss the items listed below during a group discussion:

• Centrifugal force is the tendency for an object traveling in a circular path to move outward from the center of the circle.

• Have you ever been spun on a merry-go-round? The force pushing you out away from the center of the merry-go-round is centrifugal force.

• When you go around a horizontal curve, you can imagine yourself traveling around part of a very large circle - like the merry-go-round.

• The curve must be gradual enough so that the centrifugal force is not large enough to force your vehicle off the road.

• How centrifugal force affects your vehicle depends on vehicle speed; higher-speed roads need to have more gradual curves.

• Have you ever noticed a road sign before a tight curve that warns you to slow down? It’s all because of centrifugal force.

• Think about a race car. When the car is going too fast on a curve, the car can loose control and hit the track wall or spin.

Activity: The students should set up the electric race car and track set and take turns running the race cars around the track. The teacher should point out that centrifugal force is responsible when the race car goes off the track because it is taking a turn too fast.

Draw the Viewpoints

Introduction - This activity will give students the opportunity for hands-on activity to apply information covered in Unit 4 materials.

Materials Needed - paper, pencil and an eraser.

Directions - The teacher will ask each student or group to draw the three viewpoints of the figures shown below.

       A                             B                             C

Draw viewpoint A. 

Draw viewpoint C.

Figure 2: Finish drawing the cube shown below.

TOP

What are interchanges?  

Introduction - This activity will give students the opportunity for hands-on activity to apply drawing scale information covered in Unit 4 materials.

Materials Needed - Copies of the "What are interchanges?" worksheet, blue crayon and red crayon.

Directions - The teacher will:

• Review the following Unit 4 information with the students:

"An interchange design includes ramps that allow traffic to gain speed before entering the highway and also to slow down before coming to a stop. There are many types of interchanges, but two of the most common are called diamond interchanges and cloverleaf interchanges."

• Tell the students that the drawings below are examples of the two most common interchanges.
  

• Instruct the students to:

1. Label the "diamond" interchange.

2. Label the "cloverleaf" interchange.  

          

____________________________            _____________________

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What is a drawing scale?  

Introduction - This activity will give students the opportunity for hands-on activity to apply drawing scale information covered in Unit 4 materials.

Materials Needed - Two sheets of paper, pencil, eraser, and an Iowa Transportation Map. (To request copies of the Iowa Transportation Map, contact the Iowa Department of Transportation at 515-239-1372 or e-mail cathy.mather@dot.state.ia.us.)

Directions:

The teacher will ask the students to draw the following items.

1.  On one sheet of paper, draw a house that will 
    completely fill the paper.

2.  Take the second sheet of paper and:

a.  fold the paper in half lengthwise and open
     the sheet of paper;

b.  fold the paper in half again;

c.   now draw the same house, but only fill the
     top half of the page; and

d.   in the bottom right quarter of the paper,
     draw the same house, but only fill that
     quarter of the paper.

3. Using the two pieces of paper, the teacher will lead 
    the discussion to cover the following points:

a.  The largest drawing would represent the
     actual size of the house.

b.  The house drawn on one-half of the paper
     would represent a scale of 1 to ½ to the 
     largest house drawing.

c.  Now look at the drawing made on the quarter
    page. If it is compared to the largest
    drawing, it would represent a scale of 1 to 
    1/4.

TOP

Why is a drawing scale used?  

Introduction - This activity will give students the opportunity for hands-on activity to apply drawing scale information covered in Unit 4 materials.

Materials Needed - Iowa Transportation Map, one sheet of paper, pencil, and an eraser.

NOTE:  To request free copies of the Iowa Transportation Map, contact the Iowa Department of Transportation at 515-239-1372 or e-mail cathy.mather@dot.state.ia.us.

Directions - Another way to learn about scales is to look at an Iowa Transportation Map. The teacher should review the following information with the students:

1. The map is printed on 37 1/2 " X 26 1/2" sheet of paper.
   
2. Find the map legend.
   
3. In the map legend, find the scale information.

What is the approximate scale of the map?

How many miles are represented by one inch?

  4.   Why are scales used for maps and road design blueprints? 

Activity:  The teacher will have the students draw a road map on the piece of paper.

• The map should use the scale found on the Iowa Transportation Map (1 inch represents 12 miles).

• The map should show the distance between the local town and another nearby town.