身边的科学小知识 附英文.docVIP

1、为什么星星会一闪一闪的？ 我们看到星闪闪，这不是因为星星本身的光度出现变化，而是与大气的遮挡有关。 大气隔在我们与星星之间，当星光通过大气层时，会受到大气的密度和厚薄影响。大气不是绝对的透明，它的透明度会根据密度的不同而产生变化。所以我们在地面透过它来看星星，就会看到星星好像在闪动的样子了。 Why the stars twinkling of?We see the stars shining, It is not because there are changes to the luminosity of the stars themselves, but with the block of the atmosphere. The atmosphere between us and the stars, from when the starlight through the atmosphere will be subject to the atmospheric density and thickness effects. Atmosphere is not transparent, and its transparency will change, depending on the density. On the ground through its stars, you will see stars like flashing again. 2. 为什么人会打呵欠？ 当我们感到疲累时，体内已产生了许多的二氧化碳。当二氧化碳过多时，必须再增加氧气来平衡体内所需。因为这些残留的二氧化碳，会影响我们身体的机能活动，这时身体便会发出保护性的反应，于是就打起呵欠来。打呵欠是一种深呼吸动作，它会让我们比平常更多地吸进氧气和排出二气化碳，还做到消除疲劳的作用呢。Why do people yawn?When we feel tired, the body has produced a lot of carbon dioxide. When the excess of carbon dioxide, you must increase the oxygen needed to balance the body. Due to residual carbon dioxide will affect the functional activity of our body, then the body will issue a protective response, so he yawned. Yawning is a deep breathing movements, it makes us more than the usual more sucked into oxygen and discharge carbon dioxide, but also do to eliminate the role of fatigue 3. 为什么向日葵总是朝着太阳开花？ 向日葵花盘下面茎部的地方，含有一种叫做「植物生长素」的物质。这物质有加速繁殖的功用，但却具有厌旋光性，每遇到光线时，便会跑到背光的一面去。所以太阳升起时，向日葵茎部便马上躲到背光的一面去，看起来整棵植物就向着太阳的方向弯曲了。Why do sunflowers always bloom towards the sun?Sunflower faceplate below the stem of the place, containing called auxin material. Accelerate the reproductive function of this material, but tired of optical rotation, confronted with the light, will be ran to the backlight side to go. So the sun rose, sunflower stems as soon hid the backlight side to go, looks like the whole plant toward the direction of the sun is bent. 4.为什么萤火虫会发光？ 萤火虫会发光因为在它们的腹部末端有发光器，发光器内充满许多含磷的发光质及发光酵素，使萤火虫能发出一闪一闪的光。萤火虫发光的目的，除了要照明之外，还有求偶、警戒、诱捕等用途。这也是它们的一种沟通的工具，不同种类萤火虫的发光方式、发光频率及颜色也会不同，它们藉此来传达不同的讯息。