Seeing Inside Cells

Initiate a class discussion prior to beginning the activity.

Show slide. Paraphrase:

Drawing is not just a way of recording what you see, it’s a way of seeing. While you try to figure out how to make the marks that look like what is right before your eyes, you can’t help but notice extra details and how all the parts of the thing you are seeing relate to one another.

Look at these centuries-old drawings by Leeuwenhoek ("lee-win-hoke"). He's thought to be the founder of microbiology and the creator of the microscope.

How long do you think he spent drawing each one of these? How much time would they take you to draw?

These drawings show how much you can learn by carefully looking, or having to look so closely you can record in images what you see with your eye.

In science, we use biological drawings to share findings with others, to simplify complex images and make them easier to compare, and to look closely at an organism’s structure and functions.

Have the students follow this procedure for drawing leaves with drawing partners.

1. Choose a leaf to describe to your drawing partner.
2. Without showing them the leaf, find a partner to draw it for you.
3. Working back-to-back, tell your partner every detail of your leaf, using your ruler as needed. Write down the details as you describe them.

Show slide: "Describe a leaf's size and shape."

Have students switch roles. Say:

Now you draw while your partner describes details of a leaf that you haven’t seen.

As the students draw, share the drawing tips with them.

Watch for pairs who have finished. When both students have finished describing and sketching, have them give each other the leaves.

Say:

Compare your leaf to the drawing made by your partner. Are there things you could have described more precisely?

Describe a leaf's characteristics

• Measure the length and the width of the leaf.
• What shape is it? How many lobes or does it just have one?
• Does it have a smooth outline or does the edge have teeth?
• Is one edge curvier than the others?
• Measure and describe the central vein, and other veins in the lobes. How much longer is this vein than that vein? How far apart are the veins?
• How would you describe the texture, color, or different areas of dark and light? Look for any dots or discolorations, dark areas vs. light areas, brown spots, yellow spots.
• Look for geometric patterns you can describe, like dots, straight edges, curved arcs, and repetitions.
• Are there any unusual features of the leaf?
• How do different parts relate to one another?

Your partner may ask clarifying questions. Write down your answers to their questions as details. Spend a few minutes giving your partner as many clues as you can for them to draw the leaf.

Drawing tips to share with students

• As you draw, try not to think about what the thing is that you are drawing. Draw what you see, not what you think you see. If you think about it being a leaf, you may draw it to look like all the cartoon images of leaves you’ve ever seen. Imagine you have no idea what it is. Treat the leaf like a fish or a butterfly, or even the map of a city.
• Add details, but not too much detail.
• Use sketchy lines only lightly to help place parts of the picture, and use bold, clear lines for your final drawing. Erase any sketchy lines as you finish.
• When you are done, add a title and labels.
• Measure the size of the leaf and the size of your drawing to calculate the scale or magnification of your diagram, and note it in one corner of the page.
• Write whether the view is a “top view” or a “bottom view.”

Have students draw their own leaves. Say:

Now it’s your turn to draw your own leaf with your own eyes and hands on a fresh piece of paper. You’ve just described the leaf in detail to your partner and written down the details on a piece of paper. Remember those details you shared with your partner, and incorporate those into your drawing.

Read tips from the list "Drawing tips to share with students."

Open the slide. In this section, you will help students who may have a difficult time figuring out what is “important” determine how to distill information in a diagram.

Lead a short discussion on what the students see in the drawing in comparison to the photograph. Paraphrase:

Note how the drawing of this cell sorted out important information from the tiny details. What do you notice?

Give students a chance to share their observations.

If the drawing were to include every detail, it wouldn't be a helpful diagram. The drawing simplifies the image in the slide, showing only the edge of the cell and the nucleus.

The important elements included in the drawing are labeled. The drawing also has a title with the magnification noted.

Note: Image of Pancreatic labule diagram and photo originally appeared in A Level Biology Drawing Skills Biological Drawing © OCR 2015 Oxford Cambridge and RSA Examinations

Project another microscopic image for the whole class to try drawing, or instruct the students to look at a slide in their microscopes. Alternately, students can find a microscopic image online to draw.

Direct the students:

• Describe in words what you observe in this image.
• Draw what you observe in this image.

Cell Drawing

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Ask students to share their diagrams. If you have a document camera, students could display their drawings on the projector for their classmates to see. Discuss (without judgment on artistic merit) what students found necessary to draw and what they did not.

Drawing macroscopically and drawing microscopically will be very different. Ask:

What details are important to include when drawing something large-scale (macroscopically) and what details are important when drawing what we can't see with the naked eye (microscopically)?

As you discuss the diagrams, look for things that your students did well in their first biological diagrams. For example, note diagrams that accomplish items on the list.

Ask:

Were there things you noticed in the image as you were drawing it that you didn't notice when you first saw the image?

• Diagram is drawn neatly with clear lines.
• Parts of the object / cell are noted.
• Diagram appropriately omits extraneous details.
• Diagram is accurately drawn and labeled.
• Diagram is labeled neatly without overlaps.
• Diagram includes titles and magnification.
• Color enhances understanding and is not used decoratively (if colored pencils are used).