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Lesson plan Grade 3 Art & Music

Larchwood Plant Microbes: A Grade 3 Zoom-In Drawing Lesson

Grade 3 students read a fact card on the tiny living things that clean used water at a made-up plant, then draw one large in a circle with contour line and texture.

Objectives

  1. Students will make a zoom-in drawing of one tiny living thing from a wastewater tank that fills a circular frame and uses contour line and texture marks to show its parts.
  2. Students will answer questions about a short fact card by pointing to the sentence that gives each answer.
  3. Students will write a three-sentence specimen card that tells a plant visitor what their creature is and what job it does.

Vocabulary

Floc
Floc is the fluffy clumps of dirt and treatment chemicals that form in the water during cleaning at a treatment plant. Floc looks like tiny snowflakes drifting in the water.

Also: microbe, bacteria, contour line, texture, zoom-in, specimen, leader line

Teacher overview

The Larchwood Water Reclamation Plant is a made-up plant that cleans the used water from a small town's sinks, tubs, and toilets. Its visitor room has a row of round frames that look like the view through a microscope, and the plant has asked a third-grade class to fill them with drawings of the tiny living things that do much of the cleaning in its bubbling air tanks. In this lesson students hear a short fact card read aloud, answer questions from the text, and then make a zoom-in drawing of one creature: a fuzzy floc of bacteria, a bell-shaped vorticella on its stalk, or a rotifer with its crown of hairs. The art focus is contour line, texture marks, and drawing large enough to fill a circular frame, followed by a short specimen card that tells visitors what the creature does.

Two misconceptions are common at this grade. The first is that all bacteria are harmful and that a treatment plant cleans water only with chemicals or strainers; the fact card addresses this directly by describing living things that do much of the cleaning. The second appears in the drawing itself, where children asked to draw something tiny often draw it tiny, leaving a small shape in the middle of a large empty circle. The demonstration shows that a zoom-in drawing fills the frame, because the purpose of a microscope view is to make a small thing look large enough to study.

Before class, gather two photos from any public source: a wastewater aeration tank with bubbling water, and a microscope view of activated sludge that shows brown clumps. Close-up photos of a vorticella and a rotifer are helpful for the demonstration and easy to find under those names.

Procedure

Hook (5 min): Project the photo of the aeration tank, then the microscope photo. Ask students what they notice in the second photo and record two or three observations on the board. Explain that the second photo shows a single drop of water from a tank like the first one, made to look much bigger by a microscope.

Fact card read-aloud and questions (10 min): Read the Larchwood fact card on the Student Handout aloud while students follow along. Students answer questions 1 through 6 on their own and underline the sentence in the fact card where each answer is found. Review the answers together, and ask two students to read their underlined sentences aloud for questions 3 and 4, since the bell on a stalk and the crown of hairs are the details they will draw.

Demonstration (8 min): Draw a large circle on the board to stand for the microscope window. First draw a vorticella as a small shape in the center and ask the class whether it looks like a zoom-in view. Then draw it again, large enough that the bell and stalk touch two sides of the circle. Model three steps: a light pencil contour line for the outline, a darker marker line once the shape looks right, and texture marks, with short strokes for the hairs and small dots for the fuzzy floc in the background. Finish with two leader lines, which are straight lines that run from a part of the creature to its label outside the body.

Drawing work (17 min): Each student chooses one creature and draws it in the circle on their paper, following the checklist on the handout. Circulate and ask each student which texture marks they chose for which part and why. Once the marker lines are done, students may add color with colored pencils, pressing harder on the creature than on the background. Students who finish early may add a floc or a few bacteria in the background, drawn lighter than the main creature so the eye goes to the creature first.

Specimen card (6 min): Students write a three-sentence specimen card on an index card using the frame on the handout. The card names the creature, tells where it lives, and explains the job it does in the tank.

Formative check (4 min): Partners trade drawings with the specimen cards turned face down. Each partner names the creature from the drawing alone and points to the detail that told them. Take a show of hands for drawings that were named correctly. If fewer than about three out of four were named, open the next art class with a two-minute review of contour lines and the details that make each creature recognizable. Collect the handouts to check questions 1 through 6.

Larchwood Plant Microbes: A Grade 3 Zoom-In Drawing Lesson — Grade 3 Art & Music
Name: ____________________________ Date: ______________

Student Handout

Larchwood Plant Fact Card

Used water from sinks, tubs, and toilets flows into big tanks at the Larchwood plant. Pumps blow air into the tanks, so the water bubbles all day and night. The air helps tiny living things stay alive in the water. They are too small to see with your eyes alone. These tiny living things eat the bits of waste in the water, and that helps clean it.

Bacteria are the smallest cleaners. They stick together in soft brown clumps called floc. Under a microscope, a floc looks like a fuzzy cotton ball.

A vorticella (vor-tih-SEL-uh) is shaped like a bell on a long, thin stalk. Tiny hairs around the top of the bell wave to pull in food. When something bumps it, the stalk coils up like a spring.

A rotifer (ROH-tih-fer) has a crown of tiny hairs on its head. The hairs move so fast that they look like spinning wheels. They sweep food into its mouth.

Vorticella and rotifers eat loose bacteria that float between the clumps. This helps the water get clear. Workers at the plant look at a drop of tank water under a microscope. When they see lots of these creatures, it is a good sign that the tank is working well.

Questions

  1. What do the pumps blow into the tanks?
  2. What are floc clumps made of?
  3. What shape is a vorticella?
  4. What does a rotifer use to sweep food into its mouth?
  5. What happens to a vorticella's stalk when something bumps it?
  6. What do workers look for under the microscope to tell that a tank is working well?

Zoom-In Drawing Checklist

  • Draw your creature big enough to touch at least two sides of the circle.
  • Draw the outline lightly in pencil first. Trace it in marker when the shape looks right.
  • Add texture marks. Use dots for fuzzy parts and short lines for hairs.
  • Draw two leader lines to two parts. Write the name of each part at the end of its line.
  • Keep the background light so your creature stands out.

Specimen Card Frame

This is a ___. It lives in ___. Its job is to ___.

From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.

Answer Key
  1. Answer: Air.
    The first paragraph says pumps blow air into the tanks, so the water bubbles all day and night.
  2. Answer: Bacteria stuck together.
    The second paragraph says bacteria stick together in soft brown clumps called floc.
  3. Answer: A bell on a long, thin stalk.
    The third paragraph describes the vorticella's shape in these words.
  4. Answer: A crown of tiny hairs.
    The fourth paragraph says the hairs on its head sweep food into its mouth. Accept "tiny hairs" or "its crown."
  5. Answer: It coils up like a spring.
    The third paragraph gives this detail. Students who draw the vorticella may show the stalk either stretched out or coiled.
  6. Answer: Lots of vorticella and rotifers.
    The last paragraph says that seeing lots of these creatures is a good sign the tank is working well. Accept "lots of the tiny creatures."

Differentiation

Support

Give students a circle that already has a light pencil guide shape: a cup shape and a line for the vorticella, or an oval with a crown for the rotifer. Students trace and build on the guide, which lets them spend their time on texture marks and leader lines. Read the fact card aloud a second time with a small group and let students answer questions 1 through 6 orally while an adult marks the sentence.

Extension

Ask students to divide a second circle in half with a line and draw the vorticella twice: once with its stalk stretched out and once with the stalk coiled after a bump. Discuss how two drawings side by side can show movement that a single drawing cannot, and have students add a one-sentence caption under each half.

ELL supports

Post a picture word bank with the three creatures, the words "bell," "stalk," "hair," "crown," and "clump," and a sketch next to each word. Point out cognates for Spanish speakers, such as bacteria and bacterias, and microscope and microscopio. Allow students to label their drawings with single words and to complete the specimen card frame with a partner before writing it on their own.

Extensions

Mount the finished drawings in paper circles and display them in a row as the class version of the Larchwood visitor wall, with the specimen cards underneath. If the school has a classroom microscope and prepared slides of pond water, students can compare a real microscope view with their drawings and note one detail they would add or change.