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squeaks and I were out on a walk this morning
吱吱和我今早去散步
and we both noticed lots of things are changing
我们都注意到很多事物都在变化
we found leaves that had changed color and fall into the ground
我们发现树叶变了颜色，掉到了地上
and we saw birds flying south for the winter
我们看到鸟儿在南方过冬
what else did you observe squeaks
你还注意到什么
squeak says that he found something all over the plants this morning
吱吱说他今天早上在植物上发现了很多东西
something frozen and sparkling
一些冻住还发光的东西
was it cold and just lightly covering the plants
是冷的只是稍微盖住了植物吗？
squeaks, it sounds like you found frost
吱吱，你好像找到霜了
frost is a layer of ice that can freeze over things like plants, windows and even spiderwebs
霜是一层冰，可以冻结在植物、窗户甚至蜘蛛网上
it only happens at certain times of the year
它只在一年中的某些时候发生
and it can be a special treat that shows us our seasons in action
可能是一种特殊标志向我们展示季节在变化
during fall and spring the weather is changing from hot to cold or from cold to hot which is perfect for frost
在秋天和春天，天气从热变冷，或从冷变热，这是完美的霜冻
during the day temperatures are warm enough that the air can hold on to a bit of water vapor which is water that spread out through the air as an invisible gas
在白天，温度足够高，空气可以留住一些水蒸气，水蒸气是作为一种看不见的气体在空气中扩散的水
but then as night falls and the air gets colder the gas turns into liquid water again
但是当夜幕降临，空气变冷时，气体又变成了液态水
that's why sometimes when you go outside in the morning
这就是为什么有时候你早上出去的时候
the grass is wet even if it hasn't rained
即使没下雨，草也是湿的
the water in the grass actually comes from the air there's a special name for when water in the air turns into a liquid like this
草中的水实际上来自空气，空气中的水变成这样的液体有一个特别的名字
it's called condensation
被称为凝结
the water vapor touching things like grass or Windows condenses leaving tiny drops of water over everything
水蒸气接触到草或窗户等物体时会凝结，在所有物体上留下微小的水滴
if it's only a little cold the water on the grass will stay the way this making the ground and plants a bit wet in the morning
如果只是有点冷，草地上的水就会保持这种方式，使地面和植物在早上有点湿
but when the weather is just right which is when it's warm during the day and can get very cold at night
但是当天气刚刚好，也就是当白天很热，晚上很冷的时候
the water changes one more time
水又变了一次
it freezes into ice that ice is what we call frost
它冻结成冰，冰就是我们所说的霜
and it happens when the temperature at night is below zero degrees Celsius or 32 degrees Fahrenheit
它发生在夜晚温度低于0摄氏度或32华氏度的时候
frost usually won't make ice over the entire surface of a leaf it freezes on
霜冻通常不会使整片叶子表面结冰
instead water freezes in the shape of the small drops it first made
相反，水以最初形成的小水滴的形状结冰
so it looks like little delicate freckles of ice polka dotted the whole leaf
所以它看起来就像点缀在整片叶子上的精致的冰花斑点
once morning comes you can walk outside and see beautiful froze frost on everything
一旦早晨来了，你可以走到外面，看到美丽的冰霜附在各种物质上面
it can sparkle in the bright sunlight but it won't last for long
它可以在明亮的阳光下闪闪发光，但不会持续太久
what do you think will happen to the frost squeeks
你认为冰霜挤压会发生什么
that's a good observation
这是一个很好的观察
it does look like the frost just disappears but the frost is actually changing again
看起来霜消失了但是霜又变了
later in the morning as the Sun warms up the space around it
早晨晚些时候，太阳使它周围的空间变暖
the frost starts to melt the ice might turn back into liquid water
霜开始融化，冰可能会变成液态水
or if it warms up quickly enough it can even turn right back into water vapor in the air
或者如果温度上升得足够快，它甚至可以在空气中变成水蒸气
sometimes you can even see the water vapor rising right off the ground
有时你甚至可以看到水蒸气从地面升起
it looks just like a thick fog
它看起来就像一团浓雾
frost can be beautiful to see and it's usually a sign that the seasons and weather are changing
霜看起来很美，它通常是季节和天气变化的标志
when we're going from the warm summer to the cold winter, frost means fall is here and the air and soil are about to get very chilly
当我们从温暖的夏天进入寒冷的冬天时，霜冻意味着秋天到了，空气和土壤将变得非常寒冷
people who grow plants like farmers and gardeners pay very close attention to the temperatures in fall to help keep their plants from freezing in the morning frost
种植植物的人，比如农民和园丁，会密切关注秋天的温度，以防止他们的植物在早霜中冻死
some farmers that work in places where there's lots of frost need to make sure to pick all of their crops before fall gets too cold
一些在霜冻地区工作的农民需要确保在秋天太冷之前摘掉所有的庄稼
they'll check things like how much water is in the air the temperature during the day and night
他们会检查空气中有多少水白天和晚上的温度
and how fast the wind is going
还有风的速度有多快
also they can know when the first big frost of the year will happen
他们还可以知道今年的第一次大霜冻什么时候会发生
it's like they're water scientists you can be a frost watching expert
就好像他们是水科学家，你可以当一个冰霜观察者
you can try checking the weather before bed to see how cold it will get during the night
你可以试着在睡觉前看看天气，看看晚上会冷到什么程度
and guess whether there might be frost in the morning
猜猜早上是否有霜冻
is the air above freezing before bed but going to drop down below freezing overnight
睡觉前上方的空气会结冰，但会在一夜之间降至零度以下吗
is it humid with lots of water vapor in the air
空气中有很多水蒸气时潮湿吗
make your guess
猜猜吧
then look at the ground outside the next morning to see if you were right
然后第二天早上看看外面的地面，看看你是否正确
sure, we can try it tonight squeeks
当然，我们今晚可以试试
we’ll make a field journal where we can write everything down to keep track
我们要写一份实地日志，这样我们就可以把所有的事情都写下来，以便随时跟踪
if you try this - squeaks and I would love to hear about what you learned
如果做了——那么吱吱和我很想听听你学到了什么
just ask a grown-up to help you go to our website at patreon.com slash scishow kids where you can tell us all about your results
让一个成年人帮你登陆我们的网站patreon.com slash scishow kids，在那里你可以告诉我们你所有的结果
thanks I’ll see you next time here at the fort
谢谢，下次在堡垒见
