A Learning Cycle Lesson Plan: Scale

Transcription

1 Volume 1, Number 3, Winter 2006 ISSN: A Learning Cycle Lesson Plan: Scale Cynthia Szymanski Sunal Dennis W. Sunal The University of Alabama Mary E. Haas West Virginia University Abstract This learning cycle lesson plan uses hands-on and minds-on experiences to assist fourth or fifth graders in developing the important concept of scale. The lesson focuses on enabling students to define scale as a ratio so that one square represents more squares, e.g. 1:5. It also works to enable students to draw the same object in two different scales. Grade Level: Fourth or Fifth NCSS Standards: People, Places, and Environment 436

2 Exploratory Introduction Materials: For each group, two objects that are the same except for size (e.g., two blocks of wood with one larger than a half sheet of paper and one smaller) and three half-sheets of drawing paper per student. Students identify reducing the scale of two objects as a means by which both can be drawn on paper that is too small for drawing both at full scale. 1. Place students in small groups. Have group materials manager get drawing paper and two objects that are the same except for size. Give students the task of drawing the smaller object on the half sheet of paper. Then, ask students to draw the bigger object. 2. Discuss the problems that arose, such as Is there any way you can think of to draw both of these on just one half sheet of paper? 3. Ask students to try out their ideas on another sheet of paper. Discuss results of their efforts. Ask Does your drawing show that these two objects are different sizes? Lesson Development Review final drawings to determine whether: (a) they reduced both objects to a smaller size in their drawings and (b) used the same scale for both objects, using a checklist to identify successful students in each task. Materials for pairs: 5-7 sheets of graph paper, plain paper, wood block or other square object (6 x 6 in), scissors, glue 1. Students define scale as a ratio so that 1 square represents more squares, e.g., 1:5. 2. Students draw the same object in two different scales. 1. Use common classroom materials such as pencils and books to discuss differences in size as a common aspect found among many ordinary objects. 437

3 2. Refer back to the Exploratory Introduction problem, reviewing solutions tried. 3. Assign pairs. Give each pair a sheet of graph paper and a wood block. Ask them to position the wood block so its sides are on lines. Have them draw the outline of the block, count the squares within it, and write down the number found. Have them cut out the square outlined and glue it to a piece of paper. 4. Have the students cut a graph paper square 3 rows by 3 rows and glue it on to a sheet of paper next to the 6 x 6 row square. Have students cut out a 1 ½ x 1 ½ row square and glue it near the other two squares. Talk about whether this activity suggests ideas for how they can draw something large on to a smaller piece of paper. 5. On a sheet of graph paper, ask pairs to draw a scaled drawing of a desk top or of a book that is larger than the graph paper. Work with students to establish a scale such as 1 square = 5 inches of the item. Encourage pairs to use different scales as long as the pair is successful at the task. Have pairs identify their scale on the drawing. 6. Discuss scaled down drawings, and write scales used on the board. 7. Give each student a Post-it On a checklist, record whether students produced a scaled drawing of an object that is larger than their sheet of graph paper and identified the scale used. On a checklist, record 438

4 note. Have each draw it on graph paper to size, then reduce the scale in another drawing, and label the scale for each drawing. 8. Closure. Define scale, as used here, as a ratio so that 1 square represents more squares, e.g., 1 to 5 (1:5). Discuss the different scales used in class, emphasizing that the same object can be drawn with different scales. whether students used two different scales to draw an object and labeled the scale for each drawing. Expansion Materials for each pair: yardstick, 2 sheets graph paper; for each student: graph paper, pencils Students draw a room at home to scale and accurately identify the scale used. 1. Have one pair measure the classroom s length and another pair measure its width using a yardstick. Write the measurements on the board. Ask pairs to draw it to scale on graph paper and to indicate the scale they used. Discuss their choices and drawings. 2. Ask students to measure a room at home, draw it to scale, and identify the scale used after school. 3. Discuss drawings of a room at home and scale used. 4. Lesson summary. Ask students to briefly describe their activities and what they think was the main idea of the learning cycle. Use a checklist to record whether students accurately indicated the scale used on a drawing made of a room at home. Summative Evaluation Have each student draw a scaled plan of another room in the school (e.g., library, cafeteria) using length and 439

5 width measurements for the room and a door into the room, which you provide. Ask them to indicate the location of the door to the room and identify the scale they use. Consider whether (1) the scale used was appropriate, (2) the scale was used consistently in the drawing, (3) whether the door was in the correct location, and (4) whether the door was drawn to scale. 440