1. Day 16 Yesterday, we observed paramecia under microscopes.
How did they compare to the Elodea leaf?
Have students write down as many similarities and differences as they can remember. The goal of this warm-up is to help students begin to think critically about the two organisms, which will prepare them for today’s lesson.
Elodea leaf
Paramecium 1

2. Visualization Exercise 3.4
Color
Visualization Exercise 3.4
Exercise 3.4 Image comprehension focus: Color
Rationale: The students will be using dye themselves, and also viewing images that have used dye. It is important for their understanding of these images to realize the many functions color/dye can have. This comment is designed to supplement the comment given by FOSS, further clarifying the many roles color/dye can have in both the students’ experiments as well as in images viewed.
Type of Activity: Class Discussion
Objective: To reinforce concept of how color can be used in different ways
Suggested placement: Investigation 3, part 2, activity 21 “Summarize the results”
Procedure:
During the discussion of the students’ findings, the teacher should discuss the Congo red-dyed yeast turning blue inside the paramecium.
Ask: “If you were to draw the paramecium in color, what color would you draw it?” [Some might say no color, some may suggest red (because of the Congo red-dyed yeast), and some may suggest blue (because of the Congo red-dyed yeast turning blue inside the paramecium). The teacher should reinforce the concept that the paramecium is neither red nor blue; these colors result from adding the Congo red-dye, and are not part of the paramecium itself.]
Ask: If another artist chose to color the paramecium blue, what would you be able to tell about the inside of a paramecium? [Students might say that this would mean that the paramecium must have an acidic interior]
Explain: “Because they used Congo red-dye, which is an acid indicator, blue shows there is acid. However, this does not guarantee that the artist is trying to tell the reader this fact. Other images may also use the color blue and it may mean something completely different. Whenever you see color in a diagram it is your job to ask yourself why the artist chose that color. Did they do it just to make the diagram attractive, or did they do it to help you understand something important.
Ask: “What are some other reasons that an artist might choose to use red and blue? Not just in this picture, but in other pictures as well?” [There are many reasonable answers to this question, including – ‘It is the real color of an object;’ ‘Blue might show up well, it might stand out or contrast with other colors in the picture in order to show different parts well;’ ‘Blue can mead cold, and red can mean hot.’ The point is to encourage students to come up with several reasons, and to look for reasons that are more sophisticated than answers like ‘blue is a nice color.’].
Explain: “Red and blue are very common colors used for dyes, and therefore many microscopic images will use red and blue to show the cells’ internal structure. Without a dye, these things are very hard to see.”
>>>next slide<<< 2

3. Look at page 24 in your resources book
Procedure:
During the discussion of the students’ findings, the teacher should discuss the Congo red-dyed yeast turning blue inside the paramecium.
Ask: “If you were to draw the paramecium in color, what color would you draw it?” [Some might say no color, some may suggest red (because of the Congo red-dyed yeast), and some may suggest blue (because of the Congo red-dyed yeast turning blue inside the paramecium). The teacher should reinforce the concept that the paramecium is neither red nor blue; these colors result from adding the Congo red-dye, and are not part of the paramecium itself.]
Ask: If another artist chose to color the paramecium blue, what would you be able to tell about the inside of a paramecium? [Students might say that this would mean that the paramecium must have an acidic interior]
Explain: “Because they used Congo red-dye, which is an acid indicator, blue shows there is acid. However, this does not guarantee that the artist is trying to tell the reader this fact. Other images may also use the color blue and it may mean something completely different. Whenever you see color in a diagram it is your job to ask yourself why the artist chose that color. Did they do it just to make the diagram attractive, or did they do it to help you understand something important.
Explain: “Red and blue are very common colors used for dyes, and therefore many microscopic images will use red and blue to show the cells’ internal structure. Without a dye, these things are very hard to see.”
>>>end of exercise<<< 3

4. Visualization Exercise 3.5
Labels
Visualization Exercise 3.5
Exercise 3.5 Image comprehension focus: Labels
Rationale: Labels are incredibly useful tools in identifying important information within images. A strong understanding of how to use labels will benefit students in both labeling their own images as well as in their comprehension of other images
Type of Activity: Student Activity
Objective: To reinforce the function and importance of labels.
Module Images: Resources Book page 24
Suggested placement: Investigation 3, part 2, activity 23 “Assign Homework”
Procedure:
The teacher should project the image of “Two Paramecium” found on page 24 of the resources book, and ask the students what this image is of and how they know. While the students may correctly identify the organisms as paramecia, the teacher should ask what else they can see just looking at the image.
Explain: The only information we can directly gather from the image is that they are paramecia, and they are approximately 300mu long. Any other information regarding the paramecia must be found in the text.”
Explain: “There are structures of the paramecium that are visible but have not been clearly identified in the picture. For example, we can see cilia, vacuoles, and the cell membrane”.
Ask: “What could we add to image to help point out these structures?” [Students may recall when they were previously asked to create a caption in a similar situation, and may suggest a caption here. Point out that adding a caption would be helpful for explaining something about the entire image, but there is a better way to give more information about parts of an image. If the students do not come up with ‘labels,’ then guide them to this answer.]
Explain: “Labels are a way to indentify parts of an image by writing the word and then drawing a line to that part. Use one of the paramecia in the picture to make a rough drawing in your notebooks. Make sure that all of the parts that are visible in the picture are also part of your drawing. Next, add labels to point out three different structures: 1.) vacuoles, 2.) cilia, 3.) cell membrane.” [While there might be more than one of the same structure, it is only necessary to point to one or two as an example. The teacher may want to make a rough drawing of a paramecium on the board, including just the cilia. Add a label for the cilia as an example, and instruct the students to add and label the other structures.] >>>next slide<<< 4

5. Look at page 24 in your Resources Book
Procedure:
The teacher should project the image of “Two Paramecium” found on page 24 of the resources book, and ask the students what this image is of and how they know. While the students may correctly identify the organisms as paramecia, the teacher should ask what else they can see just looking at the image.
Explain: The only information we can directly gather from the image is that they are paramecia, and they are approximately 300 microns long. Any other information regarding the paramecia must be found in the text.”
Explain: “There are structures of the paramecium that are visible but have not been clearly identified in the picture. For example, we can see cilia, vacuoles, and the cell membrane”.
Ask: “What could we add to image to help point out these structures?” [Students may recall when they were previously asked to create a caption in a similar situation, and may suggest a caption here. Point out that adding a caption would be helpful for explaining something about the entire image, but there is a better way to give more information about parts of an image. If the students do not come up with ‘labels,’ then guide them to this answer.]
Explain: “Labels are a way to indentify parts of an image by writing the word and then drawing a line to that part. Use one of the paramecia in the picture to make a rough drawing in your notebooks. Make sure that all of the parts that are visible in the picture are also part of your drawing. Next, add labels to point out three different structures: 1.) vacuoles, 2.) cilia, 3.) cell membrane.” [While there might be more than one of the same structure, it is only necessary to point to one or two as an example. The teacher may want to make a rough drawing of a paramecium on the board, including just the cilia. Add a label for the cilia as an example, and instruct the students to add and label the other structures.]
>>>end of exercise<<< 5

6. Visualization Exercise 3.6
Color
Visualization Exercise 3.6
Exercise 3.6 Image comprehension focus: Color
Rationale: It is important to reinforce the idea that colors in diagrams are used in many different ways. It is also important to develop an understanding of the differences between and functions of real images and diagrams, especially when it is hard to differentiate between them.
Type of Activity: Class Discussion
Objective: To reinforce understanding of color use in diagrams.
Module Images: Resources Book pp. 24–26
Suggested placement: Investigation 3, part 2, activity 23”Assign Homework”
Procedure: The teacher should begin by reminding the students they were supposed to think about what the color means in the images in this article. The teacher should point out the three different images of the paramecium.
Ask: “How are these three images similar to - and different from - the paramecium you viewed under the microscopes?”
Ask: “Why do you think they are different? [Allow students to explore various ways the picture differ from each other, and from what they saw under the microscope. In this discussion, be sure to follow-up on the exercise about color, making sure the students notice that the colors are very different from image to image.]
Ask: “Why do the images have these different colors? Is there a reason.?” [The images do not explicitly say why the paramecia have their respective colors, but you should reinforce answers that support the idea of using color on purpose to highlight different structures.]
>>>next slide<<< 6

7. Look at pages 24–26 in your Resources Book
Procedure:
The teacher should begin by reminding the students they were supposed to think about what the color means in the images in this article. The teacher should point out the three different images of the paramecium.
Ask: “How are these three images similar to - and different from - the paramecium you viewed under the microscopes?”
Ask: “Why do you think they are different? [Allow students to explore various ways the picture differ from each other, and from what they saw under the microscope. In this discussion, be sure to follow-up on the exercise about color, making sure the students notice that the colors are very different from image to image.]
Ask: “Why do the images have these different colors? Is there a reason.?” [The images do not explicitly say why the paramecia have their respective colors, but you should reinforce answers that support the idea of using color on purpose to highlight different structures.]
>>>end of exercise<<<
Activity Title 7