Internet version [Naruhodo no Mori] Vol.32

by Yumiko Mori

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Vol. 32     September 15th, 1997

Clouds watch

Home science experiments for mothers of elementary school children

 Tae: "Thank you, Mom! I'll take him tomorrow."
Mom: "It's OK. I have found some fun in walking."
Tae: "What is it?"
Mom: "Now I like to look at clouds. I used to like to find nice looking houses. Clouds show different shapes every day. As I walk, clouds move and change shape constantly."
Tae: "Really?"
Mom: "Have you learned about clouds in school yet?"
Tae: "Yes. I learned clouds are made of water and how clouds are formed."
Mom: "Do you know different kinds of clouds?"
Tae: "I don't know."
Mom: "You haven't heard cumulus?"
Tae: "I may have learned about cumulus, but I don't remember."
Mom: "That's understandable. I can't remember anything except cumulus."
Tae: "I can't distinguish clouds."
Mom: "There are many kinds of clouds, Tae!"
Tae: "Really?'
Mom: "There are kinds of clouds that you can predict rain or wind."
Tae: "How about clouds that become shapes of soft ice cream or cotton candy?"

Observing clouds

Required time: 5 min
It is critical to watch frequently.

Look up at the sky every time you go out.

If you see clouds, observe the entire sky for 5 min.
If possible, go to somewhere you can see all the direction, such as a roof top, a deck, a park, or a wide open road.

Study cloud shapes. Clouds can be sheet-like (stratus) or tower-like (cumulus).

Compare the altitudes where clouds are located. High altitude or low altitude?

Search for clouds which will bring rain. (The key is its altitude.)

Think why some clouds bring rain but the others don't.

Try this!

1. Dry your hands very well and grab ice.
2. Wet your hands, and swipe your hands on a towel or a handkerchief to get excess water off. Try to grab ice.

(Very wet hands are no good in this case.)

* Ice should stick to your skin. This happens because ice easily sticks to water.

The reason why rain falls

• High clouds are made of ice particles, while low clouds are made of water particles. The reason for this difference is temperature; higher in the atmosphere, lower the temperature.
  At the intermediate height, clouds are made from the mixture of ice and water particles.
  In this mixture, ice particles tend to absorb water particles, so they become increasingly larger particles. Because of their weight, these large particles fall down, resulting in rain drops.

  Cumulonimbus grows upward from lower altitude. Therefore it is more likely that ice and water particles are mixed and a lot of rain falls as the result.

• For weather prediction, observe clouds in the western sky. In Japan the weather moves from west to east.

• The cloud formation also depends on the local geography.
  Clouds form differently on the land, on the sea, and on the mountains. On the other hand, rain or snow can change the shape of mountains and rivers by scraping the earth.
  In other words the weather and the geography are closely linked each other. A landscape shapes its weather, and in return such weather shapes the landscape.
  

   Autumn is the best season to study clouds. In Autumn the weather changes constantly. I had not observed clouds so carefully, since I did for my homework when I was in my elementary school. Yesterday, I saw 'lenticular' clouds for the first time. My book says, "when you see lenticular clouds, wind will blow hard." That evening wind really picked up hard. The next morning, we had warm wind and the clouds was moving to the east. The book says "When it is warm in the morning, it'll rain." Again it rained that afternoon as the book predicted. I was impressed! This is better than the weather prediction on TV, I thought. But I don't understand why clouds can predict weather. One of my friends who works in Japanese Meteorological Agency told me that to study meteorology he needed to learn some physics, some chemistry, and some biology besides geology. If you are a meteorologist, you have to deal with the entire Earth. You have to be knowledgeable. I leave complicated cloud science to meteorologists and simply enjoy watching clouds.

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