Oakley’s workshop brings lectures to life
BRAWLEY — As it has often been advocated in the classroom, it is better to show than tell and J.W. Oakley Elementary School sixth graders here tested that proverb to limits with a handson lesson that illustrated how the human anatomy functions by examining similar livestock tissue.
Adhering to Common Core’s Next Generation science standards, sixth graders here excelled at the interactive and collaborative practicum of dissecting a cow’s eyeball, noted Principal Craig Casey.
“It can be kind of expensive but the kids have looked forward to this for weeks and really thrive with this direct pursuit,” said Casey.
Tim Dial, sixth-grade teacher, demonstrated the step-by-step process that resourcefully deconstructed the cow eye to more vividly illustrate the various parts and functions while comparing and contrasting to prior experiments.
“The first part, we remove the fatty tissue all around the eye and it is in a socket surrounded by two-thirds bone that keeps it in place when it moves,” said Dial. “The fatty tissue is a cushion so the eye does not get injured. Have your scissors resting along the eye and press against it or else your just snipping. If you can pinch the fatty tissue, it’ll come off. But most important, flip over the eye and feel the stiff chord, that’s the optic nerve, we do not want to cut that off.”
Students were asked for an analysis. The most cogent response: it felt like a fake leather jacket and looked like chewed gum, but it was not squishy like typical cow body fat.
Students next had to cut the eye in half but leave the vitreous humor, the clear gel behind the lens the lets low levels of light through. They then were able to remove the lens, the retina and cornea.
“I just scraped off the retina and where the hole is, the tapetum, (light-sensitive retinal cells enhances visual sensitivity in low levels of light) and that’s where it connects to the optic nerve and sends signals to the brain,” said Dial.
He advised students to hold a cleaned lens to the light and watch how light pours through it. Dial then asked students to contrast the cow lens with the frog lens they recently dissected. The cow lens looks like a grape skin, is oval and has a textured surface while the frog’s is smooth and round. Finally, they took the front half of the eye, turned it inside out and removed the cornea.
Expecting the cornea to be black or white, student Daniela Olivares described it as holographic blue.
“I think it’s cool we’re learning, doing this, and its fun” said Daniela. “This really feels like leather. When we first dissected frogs I was kind of squeamish. I thought I’d get body parts in my eyes and mouth. But you get used to dissecting. The reason we’re dissecting cow eyes and frogs is to learn how the parts connect in order to function and see how similar they are to our own eyes.”
Since the start of the school year, students have done close reads (in-depth) and studied various animals, noted Dial.
“With the whole movement toward STEM (science, tech, engineering and math) practical application is key and reinforces material lectured-on in class,” said Dial. “Principal Casey buys our materials every year and has been very supportive of our hands-on assignments.”