What exactly is the white we see coming off an airplane in the sky.
Sometimes in the summer you can lookup and see many streaks in the sky.
They are much longer and last longer in the summer than winter. Please
tell me what causes this and why they last longer in the summer.
The white streaks you see coming off airplanes are called contrails, which
is short for condensation trail. Contrails are actually clouds made by the airplanes.
There are two types of contrails.
Most contrails people see are caused by a jet's exhaust. The exhaust has
some water vapor in it which mixes with the air when it leaves the jet's
engine. Sometimes this mixture has too much water vapor for the air to
hold and it condenses into a cloud. This is the most common kind of
contrail and it lasts the longest.
The other kind of contrails are form by an airplane's wing.
Air moves over the wings really fast and cools because of the low
pressure. The cool air can't hold as much water so some of it has to
condense. This kind of contrail isn't as long-lived as the other kind.
The picture to the left is an example of this kind of contrail.
Contrails last longer when there is a greater amount of water in the air.
During the summer, the air generally has more water vapor in it than
during the winter. You might notice that it's usually more humid in the
summer. Because it's more humid in the summer, contrails take longer to
evaporate. That's why they last longer than in the winter.
Submitted by Stephanie (age 27, Ohio, USA)
January 16, 1998
Shop Windows to the Universe Science Store!
Learn about Earth and space science, and have fun while doing it! The
games section of our
online store includes a
climate change card game and the
Traveling Nitrogen game!
You might also be interested in:
Clouds can come in all sizes and shapes, and can form near the ground or high in the atmosphere. Clouds are groups of tiny water droplets or ice crystals in the sky and are formed by different processes.
...more
It depends on which type of motion you are asking about. If you take a birds-eye view from the top of the solar system all the planets orbit around the Sun in a counter-clockwise (or direct) direction.
...more
Almost everyone has a question or two about living in space. What do astronauts do in space? How do they do everyday things like eat, sleep and go to the bathroom? It's important to note that astronauts
...more
There is a really neat internet program called Solar System Live that shows the position of all of the planets and the Sun for any given day. If you go to that page, you'll see an image similar to the
...more
The picture of the American Flag (the one put there by the Apollo astronauts) is waving (or straight out) in the wind. How could that be possible if there is no atmosphere on the Moon? Was it some sort
...more
I was wondering if there is a new planet? Are there planets (a tenth planet?) after Pluto belonging to our solar system? What are the names of the new planets discovered in the solar system? Are there
...more
If that is so, the energy released during the Big Bang must have created many such black holes. Therefore most of the Energy of the Big bang must have disappeared in that form. Then how did the Universe
...more
