Justification Paper
User Assumptions:
This unit is designed for middle school students, ages 11-14, and can be used with special education, regular education, and gifted education students. This unit presumes no prior knowledge of microscopes, cells, or cellular function. Although individual students vary in their abilities, students should be able to read at the 5th grade level or above, work independently when directed, work cooperatively with others in a laboratory or group setting, and follow verbal and written directions. Technology skills include the ability to turn a computer on and off, to use a mouse to access the Internet and navigate to designated web sites, and to click within websites to activate interactive portions of the site.
Justification of the Design Process
Many middle school students find the study of cells to be complex and abstract. The site “Cells and Cell Processes” was designed to simplify abstract concepts and reduce cognitive load for the beginning microbiologist (Smith & Ragan, 2005). Throughout the process of designing the web site, which was created using the software Fireworks and Dreamweaver (McFarland, 2010), the principles of ACE, analyze, create, and evaluate (Lohr, 2008), were applied.
The site supplements the Prentice-Hall textbook,Cells and Heredity (2005), and works to arouse interest in the topics by providing a first exposure to the content. Individual web site pages gain the learners attention through the use of graphics designed to introduce a concept and to stimulate the learner’s attention (Smith & Ragan, 2005). By featuring one concept per web page and limiting the amount of text, information is chunked, cognitive load is reduced, and students are better able to grasp the ideas presented on the website pages (Lohr, 2008). Each page also includes a “More to Explore” section that features related links to further stimulate the learner’s interest (Smith & Ragan, 2005).
The type of information presented within the site is declarative knowledge that will be used as a foundation to accomplish the higher-order objectives found in the accompanying lessons, lessons which will deepen student understanding of cells and cell processes through the constructivist process oflearning by doing (Barah & Duffy, 2000).
In keeping with the ACE model of creating learner-friendly visuals, the typography selected for the site,Trebuchet MS, was chosen for it’s for ease of readability on a computer screen (Lohr, 2008).All blocks of text are left aligned to assist in readability (Lohr, 2008). Each page within the web site adheres to the principles of gestaltand images are concentrated, concise, and concrete to better facilitate learning(Lohr, 2008). Each page contains items that are arranged in a grid-like pattern to maintain similarity between pages; the predictable manner in which items can be found on each page reduces the cognitive load for the learner (Lohr, 2008).
In order to compensate for the fact that for the learner has little previous experience with some of the concepts, cues were added either directly to the image or to the text; this is in keeping with the gestalt principle of accessing the learner’s prior knowledge. The use of familiar objects aids the learner in connecting new information to previous experiences and knowledge.
Justification of Graphics
Home Page
The home page of “Cells and Cell Processes” is designed to stimulate the learner into making a connection between cells and various familiar organisms such mushrooms and flowers. This was done to arouse interest and motivation within the learner (Smith & Ragan, 2005). The text on the page introduces the term “cell” and gives an overview of the content found on the other pages on the site.
Microscope
One of the most important tools for studying cells is the microscope. In preparation for lab work which requires the use of a compound microscope, students will need to master the names of microscope parts. To aid the student in learning the parts, typography was used to express words by their meaning (Lohr, 2008). For example, the words“light source” are somewhat blurry and yellow to resemble an object lit up andthe words “coarse adjustment” are blurry to convey that objects viewed using coarse adjustment will be blurry.The word “look” was created using webdings which Lohr (2008) recommends using for symbols and images. The use of webdings addsan element of visual interest that encourages viewers to visualize the eyepiece as the location where they will place their eye when using a microscope. Arrows were also incorporated into the image to focus attention (Lohr, 2008) and serve to establish a relationship between the vocabulary word and the actual microscope part.All labels are close to the microscope part in keeping with the contiguity principal that says content should be placed in an integrated fashion (Clark & Lyons, 2004).
Robert Hooke
This page features several images of different objects Robert Hooke viewed when using his primitive compound microscope. All the images are enclosed in a circle which focuses attention and shows elements of a system (Lohr, 2008). Arrows, which are represented in red, move the eye outward from the center of the circle and imply that a relationship exists between the central image and the surrounding images (Lohr, 2008).The primary colors of blue and red work well together because the blue recedes to become the ground, which allows the eye to focus on the black and white images which make up the figure. Images have been enhanced with a drop shadow to provide depth, giving the illusion that the images are moving forward (Lohr, 2008). Text is placed in close proximity to the images to strengthen the idea that the text and image are related. Two questions are found within the text to stimulate reader to examine the images more carefully for detail.
Cell Theory
The timeline depicts the development of the cell theory, including the major scientists, times of discovery, and important aspects of the cell theory. The timeline is designed to further student understanding of the concept that all cells arise from previous cells.Shape and color are used to create a sense of harmony and unity (Lohr, p. 203). The blue vertical line creates a focal point that Williams & Tollett (2006) recommend for identifying important features. In keeping with the principles of CARP, images and text are aligned down both sides of the vertical timeline along paths. By using both sides of the timeline to place images and text, the aligned areas form a perceptual chunk that makes it easier for the reader to comprehend (Lohr, 2008). Williams & Tollett (2006) suggest using repetition to tie elements together; the color in the timeline is repeated in the bevels outline of the images, showing that the people are related to the timeline. The images of people appear in close proximity to their name; having the image and text together conveys the message that they are related (Lohr, 2008). Images and text that are closer together also indicate that the events occurred closer together in time.
Cellular Organization
This graphic was designed to assist learners in identifying the levels of cellular organization. It gives an overall picture of how cells are organized to create the parts that make up an organism. By arranging the pictures from organism to cell, the relationship between the images is communicated (Clark & Lyons, 2004). Uniformity and repetition were created through the use ofsimilar arrows and the inclusion of multiple hand lenses (Lohr, 2008). The use of familiar objects such as the hand lens helps the learner to interpret new information (Lohr, 2008).The use of arrows as a visual clue moves the reader through the visual from left to right and is based on the principle of contiguity which says that the mind tends to follow directional cues (Lohr, 2008; Clark & Lyons, 2004). The graphic is arranged horizontally to show the relationship between organism and cells, and also acts to assist the reader in moving through the visual in a left to right progression. Text is placed in close proximity to the images to strengthen the idea that the text and image are related.The information in the overall image is broken down into five smaller images which effectively chunks the information and breaks it into smaller parts (Clark & Lyons, p. 2004). By grouping the image, text, and hand lens, a feeling of similarity is established which reduces the learner’s cognitive load (Lohr, p. 162). The use of the hand lens is a generative strategy that encourages the reader to visualize how the images are related to each other (Lohr, 2008).
Types of Cells
This image introduces the three types of cells to students and challenges students to use their book to learn more about cell organelles. The images, which are done in primary colors that children find appealing (Lohr, 2008), have been placed on a white background, causing the images to become the figure and the background to become the ground (Lohr, 2008). In addition, images have a drop shadow which adds depth and acts to bring them to the foreground.CARP principles are evident; a blue border contains the images and acts to contrast the images against the container background. A series of rectangles provides repetition to the image and helps to chunk the information; rectangles are a good choice for containing information and focusing attention (Lohr, 2008). Since the text only consists of a few words, it has been aligned to the center of the images and is found in close proximity to the image. The elimination of organelle names acts to make the image more concise, making it easier for learners to focus on what is important.
Diffusion
Students have a great deal of difficulty understanding diffusion due to the abstract nature of visualizing the movement of molecules.The diffusion image actually consists of two images separated by white space and a blue line that chunk the information for the learner. The first image consists of a simple cell surrounded by glucose molecules; the cell contains a nucleus but no organelles. The simplicity of the cells assists the learner in focusing on what is important by reducing cognitive load. The use of arrows acts to cue the learner and helps to generate understanding of how glucose molecules move across a cell membrane (Lohr, 2008). The use of primary color, which children prefer, creates contrast (Lohr, 2008). Contrast is also achieved by the addition of drop shadows to add depth. The glucose molecules are relatively large when compared to the cell, which helps the learner to focus on them. The text is in close proximity to the cell, which tells the learner that the text and image are related to each other (Williams & Tollett, 2006). The words “Try It” are accompanied by an arrow which acts to cue the learner. These words appear in proximity to the second image, a glass of powdered drink mix. The use of a familiar phenomenon, adding powdered drink mix to water, accesses student prior knowledge and assists the learner in grasping the abstract concept of diffusion (Lohr, 2008).
Osmosis
Like diffusion, osmosis is a concept that is difficult for students to understand. The image is actually three nearly identical images separated by white space. The repetition helps to increase retention (Lohr, 2008).The images are concentrated, concise and concrete, which helps to increase learning (Lohr, 2008). For example, the image of the cell has been concentrated through the inclusion of the cell nucleus and the omission of all other organelles. Arrows, which show the direction of water movement, appear on a diagonal to add texture and energy and assist the learner in generating understanding (Lohr, 2008) by creating a mental image of molecules moving across the cell membrane.The colors blue and yellow create contrast (Lohr, 2008); blue has been used to depict the water molecules. Contrast was also created through the use of different sized text and color which emphasize the word “water” (Williams & Tollett, 2006). The graphic consists of three images; white space and a blue line have been used toseparate the images. The separation clarifies the text by separating one area of text from another (Lohr, 2008). The separation alsochunks the individual cells and their associated water molecules and text together, making it easier for the learner to focus on one cell at a time. Each area of text is in close proximity to its associated cell, which tells the learner that the text and image are related to each other (Williams & Tollett, 2006).
Mitosis
Cell reproduction, or mitosis, is often a difficult concept for students to grasp; having the process displayed in a visual manner promotes student understanding of this concept. The process of mitosis is represented in a circle, a shape that is commonly used to demonstrate processes, facilitate comparisons, and focus attention (Lohr, 2008). The images have been placed in a clockwise motion since that is a commonly understood movement; arrows are used to cue the learner and to show direction. Each phase of mitosis has been chunked; each chunk consists of an image and text placed in close proximity to the image to demonstrate relationship (Lohr, 2008). Chunking breaks the information into smaller parts which reduces cognitive load for the learner (Clark & Lyons, p. 2004). Further reductions in cognitive load are achieved through the use of depicting cells in a concrete manner by showing only the nuclear structures and no other organelles,and by establishing similarity through the use of color, arrows, and cell shapes (Lohr, 2008).
Teacher Resources
This page does not feature any graphics; it is designed to help teachers easily locate the lesson plans and unit plan.
References
Barab, S. A. & Duffy, T. M. (2000). From Practice to Fields of Communities of Practice. In D. H.Jonassen & S. M. Land (Eds.), Theoretical Foundations of Learning Environments (pp. 25-56). Mahwah, NJ: Lawrence Erlbaum Associates, Inc.
Cells and Heredity (2005). UpperSaddleRiver; NJ: Pearson Prentice Hall.
Clark, R. C. & Lyons, C. (2004). Graphics for learning; proven guidelines for planning, designing, and evaluating visuals in training materials. San Francisco, CA: John Wiley& Sons, Inc.
Lohr, L. (2008). Creating graphics for learning and performance: lessons in visual literacy (2ndEd.). Upper Saddle River, NJ: Pearson/Merrill/Prentice Hall.
McFarland, S. S. (2010). Dreamweaver CS5: The Missing Manual, Sebastopol, CA: O’Reilly Media, Inc.
Smith, P. L., & Ragan, T. J. (2005). Instructional Design (3rd ed.), Hoboken, NJ: John Wiley & Sons, Inc.
Williams, R., &.Tollett, J. (2006). The non-designer's web book (3rd Ed.). Berkeley, CA:Peachpit Press.
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