Learning Evidence and Assessment: Students will write an exit slip to answer the question “What is technical drawing?”
Academic Language: technical drawing
Lesson Opening: Draw two cats on chart paper, the whiteboard, or a SMART board. Draw the crude stick figure cat yourself. You can trace or project the cuddly, cartoon cat. Ask students to vote on which one they like better.
Learning Steps:
Ask general questions about the two images. Which one do you think is a scientific illustration and which is not? Why? What information can you get from each picture? How many toes does a cat have? Legs? Claws? How big are its eyes? What shape are its eyes? Does a cat have whiskers? Which picture would better convey what a cat is to someone that has never seen a cat before? How would you know that a cat has four legs or a tail when the cartoon shows two legs and no tail? And what are those extra toes?
Students should eventually admit that the crude stick figure has the correct details, despite the fact that it might be less appealing.
Introduce the phrase “technical drawing” to describe the stick figure image. Ask students what makes it a good technical drawing of a cat. A technical drawing should be simple, accurate, and as close to the real thing as possible. Pretend you are describing the object for someone who has never seen it before.
Lesson Conclusion: Pass out note cards or ask students to turn to the next page in their science notebooks. They will respond to the question “What is technical drawing?” You can provide the sentence stem “Technical drawing is….” or "To do technical drawing, you must..." The correct answer may include some of the following words or phrases: not cute, detailed, precise, information.
Research Connection: Technical drawing is a representation of a real object or idea that is simple, accurate, detailed and clear (Baxter & Banko, 2018). It can be a simple sketch that calls attention to the most important details of an object and “is not necessarily a beautiful or even realistic rendering of the subject” (Camacho et al., 2012, p. 69). Targeted instruction is necessary because without it, students tend to draw what they think an object should look like, not what it is (Porter et al., 2011). An example is changing the side view of an ant into a head-on smiling humanoid face, or changing a single butterfly wing into a symmetrical critter with a body and a happy face.
This lesson is taken almost directly from Camacho et al. (2012). They present their students with two versions of a drawn cat: an objectively “ugly” stick cat and an “adorable” cartoon cat. However, in parsing out the difference between the two drawings, students realize that the “ugly” stick cat is scientifically accurate and tells more about the details of a cat than the “adorable” cartoon cat. In this way, students come to see technical drawing as an important skill independent of artistic ability.