Whatever the weather

WHY IS THE SKY BLUE? The sun shines white and black light to our planet. The white light has all the colors in it. In our upper atmosphere, we have dust particles and oxygen molecules. The white light meaning all of the colours in a rainbow shines through the upper levels of the atmosphere and the blue light scatters across the entire planet. That is why our sky is blue. Now, during sunrise and sunset, the light traveling through atmosphere is longer at the horizon, then if you were to look up high in the sky. There are more dust particles and oxygen molecules at the horizon, so that is why you see such pretty colours like red, oranges and yellows.

WHAT IS WEATHER? The weather is just the state of the atmosphere at any time, including things such as temperature, precipitation, air pressure and cloud cover. Daily changes in the weather are due to winds and storms. Seasonal changes are due to the Earth rotating around the sun.

WHAT CAUSES WEATHER? Because the Earth is round and not flat, the Sun’s rays don’t fall evenly on the land and oceans. The Sun shines more directly near the equator bringing these areas more warmth. However, the polar regions are at such an angle to the Sun that they get little or no sunlight during the winter, causing colder temperatures. These differences in temperature create a restless movement of air and water in great swirling currents to distribute heat energy from the Sun across the planet. When air in one region is warmer than the surrounding air, it becomes less dense and begins to rise, drawing more air in underneath. Elsewhere, cooler denser air sinks, pushing air outward to flow along the surface and complete the cycle.

WHY DO WE HAVE SEASONS? As the Earth spins on its axis, producing night and day, it also moves about the Sun in an elliptical (elongated circle) orbit that requires 365 1/4 days to complete. The Earth’s axis is tilted at 23.5 degrees and is why we have seasons. When the Earth’s axis points towards the Sun, it is summer for that hemisphere. When the Earth’s axis points away, winter can be expected.

HOW BIG ARE RAINDROPS? Raindrops are much smaller than we think! They are actually smaller than a centimeter. Raindrops range from 1/100 inch (.0254 centimeter) to 1/4 inch (.635 centimeter) in diameter.

WHAT IS A TORNADO? A tornado begins as a funnel cloud with spinning columns of air that drop down from a severe thunderstorm. When they reach the ground they become tornadoes. Tornadoes are between 300 and 2,000 feet wide and travel at speeds of 20 to 45 miles per hour. They usually only last a few minutes, but their spinning winds, up to 300 miles per hour, can lift houses into the air and rip trees from the ground.

WHY ARE CLOUDS WHITE? Clouds are white because they reflect the light of the sun. Light is made up of colors of the rainbow and when you add them all together you get white. The sun appears a yellow color because it sends out more yellow light than any other color. Clouds reflect all the colors the exact same amount so they look white.

WHY DOES IT RAIN? We get rain when there is an area of disturbance, usually associated with a low-pressure system. The water vapor in the clouds creates droplets and those droplets keep getting bigger and bigger until the fall. When they fall, it creates rain!

HOW CAN YOU TELL WHAT TIME IT IS BY LOOKING AT THE SUN? Because the sun ALWAYS rises in the east and sets in the west, you can tell the time just by looking at where the sun is. When you look east and the sun is on the horizon that means its approximately 6:00am. When the sun is directly above your head that means its noon. When you look to the west and the sun is on the horizon that means its approximately 6:00pm.

WHY DO WE GET MORE SUNLIGHT IN THE SUMMER THAN IN THE WINTER? You might not have noticed this, but the Earth tilts over slightly. If you have a globe at home or in school, you can see that the line between north and south poles, that goes through the center of the Earth, isn’t vertical. It’s actually tilting over by about 23 degrees. In our summer, the north pole is pointing towards the Sun so the Sun rises and sets roughly from due east to due west. In winter, the Earth is on the other side of the Sun so the North Pole is pointing away from the Sun. This means the Sun rises and sets more towards the southeast and southwest. You might notice this as you look out of the window. Think back to how high in the sky the sun was during the summer. Compare this to where the sun is during the winter and you’ll see it’s much lower down towards the horizon. Because the sun is lower down on the horizon, there’s less time for it to travel between horizons. There’s less distance for it to travel so the sun rises later and sets earlier meaning there’s less daylight.

HOW DO TORNADOES FORM? Tornadoes are truly a mystery. Basically, they start as a horizontal column of air that rotates. For some reason, some of these turn vertical. Meteorologists are still unsure why this is. Once they turn vertical, they turn into a funnel cloud. As soon as they touch the ground, they become a tornado.

WHAT MAKES CLOUDS FORM RAIN? Cloud drops form when warm air cools and the water in the air condenses. With lots of drops and movement (winds and currents) the drops bump and merge until heavy enough for gravity to pull out the drops as rain.

HOW DO HURRICANES FORM? Hurricanes form in warm ocean water from an area of low pressure. Once the low starts to spin counter-clockwise, it can gain a tremendous amount of strength, but it can only do this if conditions in the atmosphere are right for development.

WHY DO CLOUDS TURN GRAY? Clouds are made up of tiny water droplets or ice crystals, usually a mixture of both. The water and ice scatter all light, making clouds appear white. If the clouds get thick enough or high enough all the light above does not make it through, hence the gray or dark look. Also, if there are lots of other clouds around, their shadow can add to the gray or multicolored gray appearance.

WHY DO CLOUDS FLOAT? A cloud forms when air heated by the sun. As it rises, it slowly cools it reaches the saturation point and water condenses, forming a cloud. As long as the cloud and the air that its made of is warmer than the outside air around it, it floats!