Heating a Test Tube to Dryness
A test tube containing liquid is heated until all the liquid evaporates. The 7 thumbnail images summarize the content of the video. Click an image to see the image gallery.
There is no narration for this video.
There is no sound with this movie.
A solution in a test tube is being heated to dryness.
A medium blue flame is used and the test tube is moved around in the flame to heat the entire surface of the tube as evenly as possible to minimize bumping and cracking.
The test tube is moved out of the flame every few seconds to allow heat to pass from the glass to the solution. This is particularly important in preventing boil-over.
The area near the liquid surface is heated slightly more than the bottom of the tube. This concentrates boiling near the surface of the liquid and reduces the potential for bumping and boil-over.
The upper portion of the tube is heated to prevent the vapors from condensing.
As the volume of liquid in the tube becomes quite small, shaking the tube gently spreads liquid out over the wall of the tube, increasing the evaporation rate and reducing the potential for bumping and boil-over.
Embedding Video in Learning Materials
The ChemEd DL encourages you to include this high-quality video in learning materials you create. We provide means to embed the video in a Web page, in a wiki, or in an online course using a course-management system. (If you want to include the video in another kind of learning material, contact us.)
If you create learning materials and make them available through the ChemEd DL, all of our videos may be freely used. For example, you can embed any video into the ChemPRIME wiki, or an online course on the ChemEd Moodle Courses site. For more information about developing resources at ChemEd DL, click here.
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Individual subscribers are permitted to incorporate video into PowerPoint or other multimedia presentations or into lessons written in HTML, provided the presentations or lessons are restricted to the subscriber’s own class (lecture presentation or course management system where only enrolled students have access). Through an institutional subscription the video becomes available for viewing by any student using a computer within the institution’s range of IP addresses. A student could also incorporate video into a report or presentation and the video would play from computers at the student’s own institution.
When this video is incorporated into other materials, this attribution should be present: Video from JCE Web Software, Chemistry Comes Alive!. Copyright ACS Division of Chemical Education, Inc. Used with permission.
In the box below is HTML code to embed this video into your own Web page. Copy the code and paste it into your Web page code.
ChemPRIME project is a full general chemistry textbook available online through the ChemEd DL. We seek collaborators to add exemplars to ChemPRIME that describe chemistry topics within various contexts, such as biological science, food chemistry, and everyday life. ChemPRIME is built using MediaWiki (the same platform used to build Wikipedia). ChemEd DL encourages users to add ChemEd DL videos to their own exemplars. MediaWiki does not allow full HTML code to be inserted, so the ChemEd DL community has created a MediaWiki extension that enables embedding videos. The extension is installed in ChemPRIME, so the code below allows you to add this video to a ChemPRIME page. More information is at ChemPRIME Help:Media. Contact us if you would like to use this MediaWiki extension on your own wiki.
ChemEd Courses is the ChemEd DL's Moodle course management system. Users can manage their own courses, or develop learning resources in Moodle to share with the community. Moodle does not allow full HTML code to be inserted, so the ChemEd DL community has created a Moodle extension that enables embedding videos. The extension is installed in ChemEd Courses, so the code below allows you to add this video to a course in ChemEd Courses. If you would like to use this Moodle extension within your own Moodle installation, contact us.
ChemPaths is the ChemEd DL's Drupal-powered integrated online textbook. Students can explore a full online textbook or other learning pathways. Instructors can sign-up to build their own pathways through course material. Drupal does not allow full HTML code to be inserted, so the ChemEd DL community has created a Drupal extension that enables embedding videos. The extension is installed in ChemPaths (currently in beta-testing), so the code below allows you to add this video to a course in a pathway. If you would like to use this Drupal extension within your own Drupal installation, contact us.