Wouldn’t it be great if scientists could control the weather? For starters, they could make sure that rain fell in all the right places - and not at picnics!
But scientists have a hard enough time simply predicting the weather, how could they possibly control it?
In the late 1960’s the United States of America (USA) attempted one of the first weather control experiments. During the Vietnam War they dropped crystals of silver iodide into clouds, hoping to increase rainfall and disrupt enemy supply lines. In 1971 North Vietnam did suffer unseasonable heavy rains, but to this day nobody knows if this was the result of the crystals or if the rain would have developed naturally.
More recently, an American meteorologist by the name of Ross Hoffman suggested that we might be able to alter the weather by nudging certain environmental conditions at appropriate moments. For example, by cooling the air in one part of the world, we might be able to cause rain somewhere else. Hoffman suggested that by monitoring current weather patterns and how small changes can cause dramatic outcomes, we should be able to learn how to tame the world’s climate.
CATCHING A CLOUD
Scientists may not be able to control the weather just yet, but there is one rather interesting weather phenomena that you can create at home. Fancy catching a cloud in a jar?
WHAT YOU NEED:
• large jar with a wide mouth
• rubber gloves
• scissors
• matches
• rubber band
• sheet of black paper
WHAT YOU DO:
1. Cut a square out of the rubber glove large enough to cover the mouth and lip of the jar.
2. Rinse the jar out with a little water, leaving enough inside to just wet the bottom.
3. Light a match and allow it to burn for a short time. Blow it out and then hold it inside the jar, allowing plenty of smoke to build up inside.
4. Drop the match into the jar and then quickly stretch the square of rubber over the jar’s mouth, securing it in place with the rubber band.
5. Pull up on the rubber square and you should be able to make a cloud appear inside the jar. Push down and the cloud will disappear.
6. A black piece of paper placed behind the jar will help you to see the cloud more clearly.
WHAT’S GOING ON?
Water exists in the air as an invisible gas called water vapour. In this experiment you were able to turn this vapour into a visible cloud of water droplets, and then back into an invisible vapour again.
When you pulled up on the rubber you stretched the air inside the jar, making it cool down a little. This caused the invisible water vapour to collect together around smoke particles and form visible water droplets - and a cute little cloud!
When you pushed down on the rubber you squashed the air inside the jar, making it warm up a little. This caused the water droplets in the cloud to break apart and form an invisible vapour once again.
The following section provides information outside the main thrust of the article… As such, it would be great if they could be ‘visually separate’? Maybe contained in a bubble… Or be in a different colour? Or whatever…!
RAINDROPS KEEP FALLING ON MY HEAD
Raindrops are shaped like tears, right? Wrong! Small raindrops form perfect spheres, while mid-sized raindrops look a little like hamburger buns. Large raindrops are the weirdest of all, shaped like upside down plastic bags with their edges rolled back!
WHAT YOU DO: