Construct the figure. Then colour it in. CREATE Technical Drawing I 17 Each workbook is split into seven units and each unit will have the following sections: At the end of each workbook there is a glossary with the most important technical terms used in each one of them. Audio files will be provided, to work on English in all its dimensions. All of this material will be worked on in just the right level of English, and will be adapted in order to be comprehensible and promote learning. How to use a compass properly: • Keep the compass lead sharp for better precision in drawing. • Place the compass needle in the centre of the circumference. • Draw the circumference by holding the handle between your thumb and index finger. • Always draw a circumference in a clockwise direction. 2 Using a compass K G s H J 90º F r D C E 90º 5 2 3 4 1 1. hinge 2. handle 3. compass lead 4. compass needle 5. adjustable centre wheel Constructions with a compass Draw a perpendicular line from a point on a straight line Given C, a point on the straight line r, follow these steps: Step 1. From centre point C, draw an arc that intersects the line r at two points, D and E. Step 2. Use D as the centre point. Draw an arc with a larger radius than in the previous step. Keep the same radius and use E as the centre point. Draw another arc that intersects the previous one at point F. Step 3. Draw the straight line CF. This is perpendicular to the line r. Draw a perpendicular line from a point outside a straight line Given G, a point outside the straight line s, follow these steps: Step 1. From centre point G, draw an arc that intersects the line s at two points, H and J. Step 2. Use H as the centre point. Draw an arc with a larger radius. Keep the same radius and use J as the centre point. Draw another arc that intersects the previous one at point K. Step 3. Draw the straight line GK. This is perpendicular to the line s. Technical Drawing I 13 Draw a perpendicular line to the line r that passes through F. Draw another one that passes through E. Draw the perpendicular bisector of the segment MN. PRACTISE r E F M N Draw parallel lines to segment AB every 5 mm. Divide the segment XY into five equal parts. A B X Y Technical Drawing I 15 Draw the perpendicular bisector of a segment AB Step 1. From centre point A and centre point B, draw two arcs that intersect at points T and U. Step 2. Draw the line UT. This is perpendicular to the segment AB and it intersects AB's midpoint. It is the perpendicular bisector of segment AB. Draw a parallel line to a straight line r that passes through an outside point L Step 1. From centre point L, draw an arc that intersects line r at point P. Step 2. Use the same radius as the previous step. From centre point P, draw an arc that intersects line r at point Q. Step 3. Use radius QL. From centre point P, draw an arc that intersects the arc from the first step at point R. Step 4. Draw line m. This is parallel to line r. Draw a parallel line to a straight line s, given the distance d between the two lines Step 1. Place two points O and M on line s. Step 2. Use the compass to draw a perpendicular line to s at O. Step 3. Use the compass to draw a perpendicular line to s at M. Step 4. Use radius d. From centre points O and M, draw the arcs that intersect the perpendicular lines at points P and Q. Step 5. Draw the straight line p, which is parallel to line s. Divide a segment PQ into equal parts (applying Thales' theorem) Step 1. Draw the ray PM at an angle to the segment PQ. Step 2. Choose any radius and draw a number of arcs on the ray PM, according to the number of divisions you want on segment PQ. Then label the intersection point of the last arc on the ray PM as point F. Step 3. Draw the segment FQ. Next, draw parallel lines to FQ that pass through the intersection points of the arcs on the ray PM. More constructions using a compass s O M P Q p d A T U B P Q F M r Q L R m P How do you sharpen the lead? • Use a 2 mm compass lead sharpener. • You can also use fine sandpaper to form a sharp bevelled edge on the compass lead. GALLERY 14 Activities, explanations, and images to put what has been learnt into practice. “Learning to learn” and “Digital skills”. We’ll apply what we’ve learnt in different activities. “Digital and entrepreneurial skills”, “Entrepreneurship” and “Cultural expression”. We’ll develop our knowledge of technical drawing and expand the use of techniques. We’ll work on “STEAM” and “Social and civic skills”. CONTENT: The content of the unit is introduced, with examples showing how to make the constructions step by step. We will work on “Maths, Science and Technology (STEAM) skills”. PRACTISE CREATE GALLERY
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