PBS高端访谈:通过点燃圣诞树来表达对科学的热爱

 　　GWEN IFILL: Every year, fire departments in the United States respond to more than 200 Christmas tree fires, which are often more deadly than other house fires.

　　Tonight, we take a look at a program at the University of Maryland that uses Christmas tree burns to teach high school students, not only about fire safety, but about the relevance¹ of science and math.

　　The "NewsHour"'s April Brown has this report, part of our American Graduate series, a public media initiative funded by the Corporation for Public Broadcasting.

　　APRIL BROWN: This time of year, most people would buy a Christmas tree to make the holidays more festive². But scientist Isaac Leventon has a completely different plan for this one, which hasn’t had any water for a week. It’s all in the name of science.

　　ISAAC LEVENTON, Doctoral Candidate, University of Maryland: What’s really making us safe right now is, there is nothing within that tree for a good 10, 15 feet that can actually catch on fire.

　　APRIL BROWN: Leventon is a graduate student at the University of Maryland in the Department of Fire Protection Engineering. His large-scale, controlled burn of this tree and two others is the finale for a fire science class he created for high school students.

　　ISAAC LEVENTON: I think everyone at some point likes playing with fire, and that kind of keeps you here.

　　APRIL BROWN: The 10th and 11th graders will gather data from each burn, and eventually compare the heat release rates to determine which fire is more powerful. The class is free for the dozen students who live near the College Park campus and are accepted into the eight-week program.

　　ISAAC LEVENTON: That’s a really large fire. Whenever you see that amount of energy, now you know what that feels like.

　　APRIL BROWN: Leventon started it two years ago, with the goal of using fire to spark and grow interest in science, technology, engineering, and math, collectively known as the STEM fields, which experts say are critical to America’s future economic competitiveness.

　　But some educators have struggled to make these subjects engaging and relevant. In this class, setting fires does both.

　　ISAAC LEVENTON: For a number of them, you now have to study calculus³ and chemistry and physics. In the one semester we have, I can’t teach them all of these things, but I can show them, here is how we can use basic chemistry to predict the temperature of any flame of our material, and then you can say, OK, maybe chemistry has an application.

　　APRIL BROWN: Students like Erin Stewartson and Pablo Ruiz do not receive high school or college credit for taking the class, which makes it all the more impressive they show up every other week for several hours after school.

　　ERIN STEWARTSON: My school doesn’t have an engineering program. And to do this for free, like, even if you don’t get credit, it’s still very good knowledge you can use.

　　PABLO RUIZ: It’s definitely given me a more solid idea of what engineering will be like.

　　APRIL BROWN: Some lessons are basic, like how a candle stays lit.

　　PABLO RUIZ: You have your ignition, and then kind of melts. And then the wick absorbs the wax. And then that melted wax, it evaporates, and then that’s what’s burning is that evaporated wick. It’s called fuel vapor⁴. And that constantly burns until you put it out.

　　APRIL BROWN: Other are more complex, including one on fire tornadoes⁶. Erin Stewartson wanted to learn more about them, so she and Leventon created one in the lab.

　　ERIN STEWARTSON: So, a fire tornado⁵ is basically a normal fire plume⁷, which is just something lit on fire, and then, when its — when an enclosure goes over it, which is like a rectangular enclosure, it creates like an angular momentum⁸, which makes the fire spin into like a tornado, like a whirl.

　　And they actually do exactly what tornadoes do. Like, they pick people up and they take trees out of places, which is pretty crazy, how it forms. And just, like, seeing it happen in the lab, that was pretty amazing too.

　　APRIL BROWN: The class is structured just like a university level science course, with similar expectations and course work, like labs and tests. Here, though, the final project is presented to classmates and parents.

　　STUDENT: In America, there were 365,000 catastrophic house fires reported.

　　ISAAC LEVENTON: So it’s not just study something, measure something and present it, but really learn about what’s happening in the field and what are people doing and why does that matter.

　　APRIL BROWN: The introduction to what college classes will be like and discussion of potential career are two reasons Pablo’s mother, Norma Ruiz, is glad her son signed up.

　　NORMA RUIZ, Pablo Ruiz’s Mother: I think there should be more of these opportunities for high school students, especially the ones interested in engineering and the sciences, so that they can get a better idea of what they want before they actually get to college, because there’s nothing better than getting to college knowing what you want.

　　APRIL BROWN: Back in the lab, students continue to gather data, this time from a tree that’s been soaking in water for two weeks. It takes nearly five minutes for it to catch fire, compared to the drier tree which was almost fully⁹ consumed in less than a minute.

　　ISAAC LEVENTON: It’s valuable to see how the fire is going to behave and know what that’s going to feel like. So we get that out of our tests. I wrote a number for what size fire it is. And knowing, OK, an 800-kilowatt fire, that means tree is burning 14 feet up into the ceiling, and I can feel it from 30 feet away, that’s — that’s just invaluable¹⁰ experience.

　　APRIL BROWN: And even though Leventon is expected to get his Ph.D. very soon, the department hopes to find someone who can continue the class. A grant to fund it next year has already been approved by the Society of Fire Protection Engineers.

　　I’m April Brown in College Park, Maryland, for the “PBS NewsHour.”

1 relevance   

n.中肯，适当，关联，相关性

参考例句：

• Politicians' private lives have no relevance to their public roles.政治家的私生活与他们的公众角色不相关。
• Her ideas have lost all relevance to the modern world.她的想法与现代社会完全脱节。

2 festive   

adj.欢宴的，节日的

参考例句：

• It was Christmas and everyone was in festive mood.当时是圣诞节，每个人都沉浸在节日的欢乐中。
• We all wore festive costumes to the ball.我们都穿着节日的盛装前去参加舞会。

3 calculus   

n.微积分；结石

参考例句：

• This is a problem where calculus won't help at all.对于这一题，微积分一点也用不上。
• After studying differential calculus you will be able to solve these mathematical problems.学了微积分之后，你们就能够解这些数学题了。

4 vapor   

n.蒸汽，雾气

参考例句：

• The cold wind condenses vapor into rain.冷风使水蒸气凝结成雨。
• This new machine sometimes transpires a lot of hot vapor.这部机器有时排出大量的热气。

5 tornado   

n.飓风，龙卷风

参考例句：

• A tornado whirled into the town last week.龙卷风上周袭击了这座城市。
• The approaching tornado struck awe in our hearts.正在逼近的龙卷风使我们惊恐万分。

6 tornadoes   

n.龙卷风，旋风( tornado的名词复数 )

参考例句：

• Tornadoes, severe earthquakes, and plagues create wide spread havoc. 龙卷风、大地震和瘟疫成普遍的毁坏。 来自互联网
• Meteorologists are at odds over the working of tornadoes. 气象学者对龙卷风的运动方式看法不一。 来自互联网

7 plume   

n.羽毛；v.整理羽毛，骚首弄姿，用羽毛装饰

参考例句：

• Her hat was adorned with a plume.她帽子上饰着羽毛。
• He does not plume himself on these achievements.他并不因这些成就而自夸。

8 momentum   

n.动力，冲力，势头；动量

参考例句：

• We exploit the energy and momentum conservation laws in this way.我们就是这样利用能量和动量守恒定律的。
• The law of momentum conservation could supplant Newton's third law.动量守恒定律可以取代牛顿第三定律。

9 fully   

adv.完全地，全部地，彻底地；充分地

参考例句：

• The doctor asked me to breathe in,then to breathe out fully.医生让我先吸气，然后全部呼出。
• They soon became fully integrated into the local community.他们很快就完全融入了当地人的圈子。

10 invaluable   

adj.无价的，非常宝贵的，极为贵重的

参考例句：

• A computer would have been invaluable for this job.一台计算机对这个工作的作用会是无法估计的。
• This information was invaluable to him.这个消息对他来说是非常宝贵的。