Kent City — In preparation for their fat-burning experiment, Kent City Middle School seventh-graders Jocelyn Reason, Scarlett Smith and Michael Christian meticulously prepared their lab materials.
Michael carefully filled one tealight candle holder with 2 milliliters of vegetable oil and one with the same amount of duck fat.
Scarlett and Jocelyn used a digital scale to measure and record the mass of the substances, plus the mass of the candle wick.
In their lab notes, they jotted down observations of the substances in each container:
“It is clear,” they wrote of the liquid vegetable oil.
“It’s kind of foggy,” was the description of the semi-solid duck fat.
Then came the main event: fire. Teacher Tara Lafferty carefully lit the wick in both substances and the seventh-graders scrambled to note their observations as they watched each one burn, side by side.
“That one actually looks darker now,” said Scarlett, pointing to the duck fat as she knelt to get a closer look.
“I think it looks kind of clear. Wait, why are they both clear?” Michael asked as Lafferty passed by their table. But the teacher wasn’t handing out any answers.
Thinking, Observing, Burning
The fat-burning lab in Lafferty’s science class is part of a multi-week unit in which seventh-graders learn about systems of the body and the scientific processes that must occur in order for the body to function properly. They do this by studying the medical tests and symptoms of a girl named M’Kenna, a teenager whose real-life health mystery has been turned into a science unit for teachers.
In this lesson-within-a-unit, the students used M’Kenna’s weight chart to study energy cycles and metabolism. One of the girl’s symptoms was that she had been losing weight. So Lafferty posed some questions to the class: “Where is all of her weight going? What’s happening to it? What is she losing — is she losing fat, or something else?”
The fat-burning lab, Lafferty said, was designed to get kids thinking about, and observing, physical changes that occur when different types of fat are burned.
“They’re noticing that the different fats burn off the energy differently,” Lafferty said. “The vegetable oil gives off more smoke than the other one, so what can we assume by that? Probably that the vegetable oil gives off more carbon dioxide — more ‘stuff’ to burn.
“But we’re not there yet. Right now I want them to just be asking questions: ‘Where do those fat molecules go? What other things can we measure?’”
Learning ‘the whole big picture’
Lafferty’s students will be able to put those questions and observations to use as they go on to study the cycle that occurs as the body processes food.
“They should be making the connection that those molecules are coming in as glucose, (then) it’s burned to (provide) energy and now it’s turning into something else,” she said. “You’re breathing it out as carbon monoxide, you’re pooping it out or you’re sweating it out — one of those things is happening. And then you have to eat again for it to start all over.”
Woven into this study is an age-appropriate lesson in nutrition as well, as the class discusses things like “good fats” and studies M’Kenna’s weight chart logged by her doctor. They learn what terms like “50th percentile” mean and why a lunch that consists of a bag of chips and a cookie might not be feeding their bodies well.
“It’s a great conversation to have with seventh-graders: You should be gaining weight in a healthy way, along this line on your chart that your doctor can show you,” Lafferty said. “Those lines show what’s supposed to happen with your growth — but kids don’t know the why or how it matters.
“I usually try to encourage students at this age to start being engaged when they go into the doctor’s office, because it’s learning more about their own bodies. … We do a lot of social studies in here, a lot of math, (and) a lot of science, all at the same time, because it all interacts and comes together in how their body works. It’s about the whole big picture of everything.”
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