Nicholas Academy
Google
 
Web nicholasacademy.com
Click here to buy posters!
Click here to buy posters!



Science Experiment of the Week
300 - A Watched Pot


Never Boils Boiling Water Vapor
From Robert Krampf's Science Education Company. To start receiving the
Experiment of the Week, just send a blank E-mail to: krampf-subscribe@topica.com


 






This Week's Experiment - #300 A Watched Pot

This week's experiment came from last week's research. As I was boiling each vegetable sample, I had quite a bit of time to watch the water boil. If you tried the experiment, then you probably spent some time watching too. Did you notice all the strange things the bubbles did? No? Then it is time to go back to the stove and boil some water. You will need:

a pot with a lid
a stove
water
patience

Fill the pot about half full of cold water. Place the pot on the stove burner and turn on the heat. Now get comfortable and watch. Keep watching. Watch some more.

As the pot and water heat up, you will notice tiny bubbles forming on the bottom and sides of the pot. These first bubbles are not the start of boiling. Instead, they are from dissolved gases being driven out of the water. Still, these bubbles are important, as they will serve as starting points for the bubbles produced by boiling.

As the water heats more, the process of boiling begins. Heat causes the molecules of water to move faster and faster. When they are moving fast enough, they break away from the other molecules and change from a liquid to a gas. The molecules of water leap into the tiny bubbles we saw earlier. This forms a bubble of water vapor. When the bubble gets large enough, it breaks free and begins to rise. Watch closely and you will see an amazing thing. The bubble vanishes before it reaches the top of the water!

Where did it go? Heat from the pan caused the water molecules to move fast enough to become a gas. When the bubble begins to rise, it moves through the cooler water in the upper part of the pot. This cooler water condenses the water vapor back into liquid water and the bubble disappears.

As the water in the pot gets hotter and hotter, it finally reaches the point where the bubbles reach the surface. Now you need to watch very closely to see the next amazing thing. Some of the bubbles pop, but most do not. Instead they shrink and disappear. The same thing is happening, but this time it is the cooler air that causes them to condense back into liquid.

The next step is to put the lid on the pot. Very quickly you will probably find that the pot is boiling over. Bubbles and liquid begin to come out from under the lid. Carefully lift the lid and you will see that the pot is full of bubbles. Almost instantly, the bubbles go away and the pot is once again just boiling water. Why does putting the lid on make the pot boil over? Think for a minute. With the lid off, the cool air caused the bubbles to collapse. With the lid on, the air inside the pot gets hot enough to keep the water vapor in its gaseous form. More and more bubbles develop and the pot quickly fills with foam and boils over. When you lift the lid, cooler air comes in contact with the bubbles and they go away.

All of this boils down to the fact that while watching a pot will not keep it from boiling, keeping the lid off to watch it will help keep it from boiling over.

From Robert Krampf's Science Education Company
PO Box 60982
Jacksonville, FL 32236-0982
904-388-6381
krampf@aol.com

To start receiving the Experiment of the Week, just send a blank E-mail to: krampf-subscribe@topica.com


Science Experiments Index
211 - 220 221 - 230 231 - 240 241 - 250
251 - 260 261 - 270 271 - 280 281 - 290
291 - 300 301 - 310 311 - 320 321 - 330
331 - 340 341 - 350 351 - 360 361 - 370









space items
Space Items
ant farms
Ant Farms
DNA Explorer
Forensics
electronics
Electronic Kits

Nicholas Academy Index

Middle Age & Renaissance


Foreign Language


Language Arts


Math


Music


Creativity


Science


Social Studies


Science Experiments


Space Items for Kids


Fun Science Kits


Fun Electronic Kits


Educational Posters


Educational Coloring Books


Courses


Exercises


Printables


Useful Tools


Testing & Assessment


Bargain Books


Website Building


Freebies & Bargains


Site Map



Educational Poster Store

Hundreds of educational posters in different subject areas. Parts of speech, medieval, solar system, biology, world maps, Einstein, Martin Luther King. Science, math, literature, art, music, english, geography, social studies. If you don't know exactly what you're looking for, this is great to browse for ideas.
Free Before You Know It™ Software Download

Download a full working copy of Before You Know It Lite, plus a collection of lists for your chosen language. It's free and you can use it forever, with no time or session limits. 42 languages to choose from.
NASA Website Links

Educational resources include worksheets such as mazes, coloring pages, shuttle model instructions, crossword puzzles, space food tray instructions and grocery list, and more. See the Space Station Sky Watch, view a NASA Astronaut Application or the Space Shuttle Launch Schedule, learn about the U.S. Space Camp and Women in Spaceflight.


Get a free Zoobooks issue and a tiger poster. Zoobooks are the all-in-one, everything-you-wanted-to-know but-didn’t-know-who-to-ask guide to the world’s most fascinating animals, birds, reptiles, and insects. For kids five to twelve.


Subscribe to Nicholas Academy Educational Resources
Parents - Teachers - Students - Homeschoolers
Keep informed of the newest resources we find, and of any new sections we add to the site. This list is also for general conversation and for sharing your own favorite educational resources.
 
Powered by groups.yahoo.com



If you have comments, questions, or would like to
report a broken link, please send an email to Cheryl at
gorillacheeze@aol.com

© 2000-2008 Nicholas Academy
Nicholas Academy Site Map