【小故事】一次有趣的实验小故事：教室里的火山

教室里的火山，是我们四个喂大的

科学课前三天，我们小组四个人就开始忙那座火山了。火山是糊出来的：先拿一个空矿泉水瓶当火山口，瓶身上糊报纸，一层一层，糊出山坡的形状。李多多负责撕报纸，我负责调浆糊，王响把报纸按在瓶子上抹平，坐在最后一排的赵一诺手最巧，山坡的纹路都是她压出来的。

糊好的火山晾在教室后墙，第二天干了，灰扑扑的，像一座真的小山。李多多拿红颜料在山坡上刷了几道，说这是岩浆流过的痕迹。王响说那得先让它流出来才算。我们四个对视一眼，都等着科学课那天。

科学课终于来了。老师把小组的材料一样一样摆上桌：白醋、小苏打、洗洁精、红色食用色素，还有一把小勺。我们组的火山摆在桌子正中间，全班四十多双眼睛围着它。老师朝我们点头，意思是开始吧。

我往火山口里倒白醋，咕咚咕咚，醋味冲上来，前排几个女生捏住了鼻子。李多多逗她们：憋住，好戏在后头。王响把小苏打倒进纸槽，赵一诺往醋里滴了两滴色素、挤了一滴洗洁精，搅了一下。然后王响把小苏打顺着纸槽倒进火山口。

一秒，两秒，火山口里先是鼓起一个泡，接着咕嘟咕嘟响起来，红色的泡沫涌上来，漫过火山口，顺着报纸糊的山坡往下流。全班哗地一声惊呼，后排有人喊：喷了喷了！有人从座位上站起来，凳子刮得地板响。老师拍了一下桌子说安静，可他自己也在笑。我们四个手忙脚乱，我扶火山，李多多递纸巾，王响举着手机拍，赵一诺喊流到桌子边了快接住。

泡沫流了火山半山坡，慢慢停了。全班还围着不肯散，隔壁班的人都扒着门框看。老师问我们：知道为什么冒泡吗？李多多抢着说：醋跟小苏打打架了！全班大笑。老师也笑：差不多，它们反应生成二氧化碳，泡泡就是气体跑出来。李多多得意地环视一圈，像真的打赢了一架。

下课铃响了，我们四个舍不得拆火山，把它抬到后墙放好。那座灰扑扑的报纸山，山坡上还留着干掉的红色印子。后来每次路过，李多多都要拍它一下说：喂，你什么时候再喷一次。它当然不回答。可我们四个都记得那个上午，记得醋的味道、红色的泡、全班整齐的惊呼。科学原来不是书上的字，是冒出来的泡，是大家一起喊出来的那一声。

The Volcano in Our Classroom, Fed by the Four of Us

Three days before science class, the four of us in the group had already been busy with the volcano. We built it by pasting: an empty plastic bottle as the crater, layers of newspaper pasted over the bottle into the shape of a slope. Li Duoduo tore the paper, I mixed the paste, Wang Xiang pressed the paper onto the bottle and smoothed it, and Zhao Yinuo, who sat in the last row, had the cleverest hands. Every ridge on the slope was pressed out by her.

The finished volcano dried against the back wall overnight, gray and dusty, like a real little mountain. Li Duoduo brushed a few red streaks down its slope and said these were traces of lava. Wang Xiang said it would only count once the lava actually flowed. The four of us looked at each other, all waiting for science class.

Science class finally came. The teacher laid out the group materials one by one: white vinegar, baking soda, dish soap, red food coloring, and a small spoon. Our volcano sat in the middle of the table, more than forty pairs of eyes circling it. The teacher nodded at us. Begin.

I poured white vinegar into the crater, glug glug glug, the sour smell rushed up, and a few girls in the front row pinched their noses. Li Duoduo teased them: hold your breath, the good part comes after. Wang Xiang poured baking soda into a paper trough. Zhao Yinuo dropped two drops of coloring and one drop of soap into the vinegar and stirred. Then Wang Xiang tipped the baking soda down the trough into the crater.

One second, two. A bubble swelled in the crater, then it began to gurgle, red foam rising over the rim, running down the newspaper slope. The whole class burst into a gasp. Someone in the back shouted: it's erupting! Chairs scraped the floor as kids stood up. The teacher slapped the desk for quiet, but he himself was grinning. The four of us scrambled: I steadied the volcano, Li Duoduo handed tissues, Wang Xiang held up his phone to film, and Zhao Yinuo shouted that the foam had reached the edge of the table, catch it.

The foam ran halfway down the slope and slowly stopped. The class still would not scatter; kids from the next class pressed against the doorframe to watch. The teacher asked us: do you know why it bubbled? Li Duoduo blurted: the vinegar and the baking soda had a fight! The class roared with laughter. The teacher laughed too: close enough. They react to make carbon dioxide, and the bubbles are the gas escaping. Li Duoduo looked around smugly, as if he had truly won a fight.

The bell rang, and we could not bear to take the volcano apart, so we carried it back to the wall. The gray paper mountain still had dried red streaks on its slope. Ever since, whenever Li Duoduo passes it, he gives it a pat: hey, when will you erupt again? Of course it does not answer. But all four of us remember that morning, the smell of vinegar, the red bubbles, the whole class gasping at once. Science, it turns out, is not words in a book. It is bubbles rising, and that one shout everyone lets out together.

全班惊呼的那一秒，我在扶我的火山

分组做火山实验的时候，组长分活：陈晨捏模型，刘子洋倒醋，孙嘉嘉加小苏打。分到我，她说：周小舟，你扶着火山，别让它倒。我说好。我话本来就少，组里说什么都说好。

模型是用橡皮泥裹纸杯做的，陈晨捏得很快，山坡、沟壑，连山脚的石头都捏出来了。等待晾干的那节课，我们组三个人围着模型商量谁倒醋谁加粉，商量得很热闹。没有人问我。我在旁边把抹布叠了又叠，把桌角的水渍擦了三遍。

科学课那天，火山架在托盘里。刘子洋捏着量杯沿杯壁倒白醋，倒得很慢，很稳，像在做一件了不起的事。醋味散开，前排有人咳嗽。孙嘉嘉用小勺舀小苏打，一勺，两勺，第三勺倒进去的时候手抖了一下，粉末洒在山坡上一小片。

然后，火山口开始冒泡。先是小小的，像烧开的米汤，然后泡泡连成串，橙红色的泡沫漫出杯口，顺着山坡淌下来。全班炸开了，惊呼，鼓掌，有人喊我们组的火山最猛。陈晨举手跟老师报告：我们加了洗洁精！刘子洋举着空量杯到处给人看。孙嘉嘉跳起来，马尾一甩一甩。

而我，在扶我的火山。泡沫涌上来的时候火山晃了一下，我双手扣住杯身，稳稳按在托盘上，一直按到泡沫平息。没有人喊周小舟真棒，也没有镜头对着我。可我按着那座滚烫的、湿漉漉的火山，听着全班整齐的惊呼从头顶罩下来，心里有什么东西跟着那些泡泡一起涌上来了。

收器材的时候，组长陈晨忽然说：幸好小舟一直扶着，不然火山早倒了，泡沫都喷到桌上了。组里三个人一起回头看我。刘子洋说：对，多亏你。我说不客气，耳朵还是热了。原来我做的不是扶火山，我做的，是让火山可以安心喷发。

后来科学老师讲二氧化碳，我在下面听，想起那天的泡泡。我不爱说话，可我那双手扣得住一座摇晃的火山。教室里的欢乐像一场喷发，人人都在喊，而我知道，喷发的那一刻，总得有人稳稳地扶着。下一次实验，我还是会坐在组里，等那只分给我的活。

The Second the Class Gasped, I Was Holding Up My Volcano

When our class split into groups for the volcano experiment, the group leader handed out jobs: Chen Chen shaped the model, Liu Ziyang poured the vinegar, Sun Jiajia added the baking soda. My turn came, and she said: Zhou Xiaozhou, you hold the volcano steady so it does not tip. I said okay. I am a quiet person. In a group, I say okay to everything.

The model was a paper cup wrapped in clay. Chen Chen worked fast: the slope, the gullies, even the stones at the foot. During the waiting period while it dried, three of our group chatted busily about who would pour the vinegar and who would add the powder. Nobody asked me. Beside them, I folded the rag over and over and wiped the water stain on the table corner three times.

On the day of science class, the volcano stood in its tray. Liu Ziyang pinched the measuring cup and poured white vinegar down the inner wall, slow and steady, like a man doing something great. The sour smell spread; someone in the front row coughed. Sun Jiajia scooped baking soda with a small spoon: one scoop, two. On the third her hand trembled, and a little powder scattered across the slope.

Then the crater began to bubble. First small, like boiling rice soup, then the bubbles came in strings, orange-red foam spilling over the rim and running down the slope. The class exploded: gasps, applause, someone shouting that our volcano was the fiercest. Chen Chen raised her hand to report to the teacher: we added dish soap! Liu Ziyang waved his empty cup at everyone. Sun Jiajia jumped, her ponytail swinging.

And I was holding up my volcano. When the foam surged, the volcano rocked, and I clamped both hands around the cup, pressing it firm against the tray, holding until the foam settled. Nobody shouted that Zhou Xiaozhou did great; no camera pointed at me. But I held that warm, wet volcano, listening to the whole class gasp above me, and something inside my chest rose along with those bubbles.

While packing up, Chen Chen suddenly said: luckily Xiaozhou held it the whole time, or the volcano would have tipped and sprayed the whole table. The three in our group turned to look at me. Liu Ziyang said: right, thanks to you. I said you are welcome, my ears still hot. So what I did was not just holding a volcano. What I did was let the volcano erupt with peace of mind.

Later, when the science teacher explained carbon dioxide, I listened from my seat and thought of those bubbles. I do not talk much, but these two hands of mine can hold a rocking volcano steady. The joy in a classroom is like an eruption: everyone shouts, and I know that in the moment of eruption, someone must always be holding on firmly. Next experiment, I will still sit in the group and wait for the job that comes to me.