Quantcast
atla.doereport.comatla.doereport.comBiology: Chemistry in Biology: 07: Van der Waals Forces - Medical Animation
Biology: Chemistry in Biology: 07: Van der Waals Forces - Medical Animation



or
Search Language
Browse
Medical Illustrations
Medical Exhibits
Medical Animations
Medical Animation Titles
Medical Encyclopedia
Custom Interactive
Most Recent Uploads
Body Systems/Regions
Anatomy & Physiology
Cells & Tissues
Abdomen
Back and Spine
Foot and Ankle
Hand and Wrist
Head and Neck
Hip
Knee
Shoulder
Thorax
Medical Specialties
Anesthesiology
Cancer
Cardiology
Dentistry
Emergency Medicine
Gastroenterology
Infectious Diseases
Neurology/Neurosurgery
Nursing Home
Ob/Gyn
Orthopedics
Pathology
Pediatrics
Personal Injury
Plastic Surgery
Psychiatry
Radiology
Surgery
Urology/Nephrology
Account
Administrator Login
 
6/6/20
Biology: Chemistry in Biology: 07: Van der Waals Forces - Medical Animation
 
This animation may only be used in support of a single legal proceeding and for no other purpose. Read our License Agreement for details. To license this animation for other purposes, click here.

If animation does not play, download and install the latest free Flash Player plugin.
More Like ThisAdd To Lightbox NSV16025 Enlarge Share
Ready to Purchase?

$999.00

Order by phone: (800) 338-5954
Item #NSV16025Source #1136

Biology: Chemistry in Biology: 07: Van der Waals Forces - Medical Animation
MEDICAL ANIMATION TRANSCRIPT:
In this video, we'll discuss Van der Waals forces. Van der Waals forces are forces of attraction between molecules that are very close together. These forces between molecules are much weaker than the chemical bonds between the atoms holding a molecule together. Let's see how Van der Waals forces work. Molecules are electrically neutral because they have equal numbers of positively charged protons in the nucleus and negatively charged electrons outside the nucleus. In addition, some molecules are also polar. What does this mean? Well, polar molecules have permanent poles of electrical charge like a magnet because the electrons are unevenly distributed around the molecule. How does this happen? Let's look at an example of a polar molecule, water. A water molecule, or H2O, consists of two hydrogen atoms and one oxygen atom. When a water molecule forms, both hydrogen atoms bond with the oxygen atom by sharing their electrons with the oxygen atom. This completes both oxygen's outer electron shell, which can hold all eight electrons, and hydrogen's outer shell, which can hold two. However, the electrons aren't shared equally between the atoms because the oxygen atom attracts the electrons more strongly than hydrogen. As a result, a partial negative charge develops around oxygen because there are more negatively charged electrons around the oxygen side of the molecule. In comparison, fewer electrons around the hydrogen atoms create a partial positive charge on the hydrogen side of the molecule. This unequal sharing of electrons creates opposing poles of electrical charge on either side of the two bonds that hold the atoms together. Because of the opposite poles, these bonds are called polar covalent bonds. And since a water molecule is angled or bent with both of the hydrogen atoms on one side and the oxygen atoms on the other side, the molecule as a whole also has opposite poles and therefore is referred to as a polar molecule. Now, when polar molecules are near each other, a Van der Waals force of attraction between the molecules occurs because of their oppositely charged poles. In this example, the attraction of a polar molecule's negative pole to the positive pole around hydrogen atoms in water is a particularly strong type of Van der Waals force called a hydrogen bond. Hydrogen bonds only occur in polar molecules between hydrogen in one molecule and oxygen, nitrogen, and fluorine in the other. If a molecule doesn't have permanent poles of opposite electrical charge, it's called a non-polar molecule. However, non-polar molecules can become polar for very brief moments since the locations of electrons around atoms are constantly changing. This means the molecule can have a temporary negative pole on the side where there are momentarily more electrons, and a temporary positive pole on the opposite side where there are fewer electrons. The momentary concentration of electrons in this molecule's negative pole can repel the electrons in a nearby molecule toward its opposite end, making the neighboring molecule polar as well. The oppositely charged poles of adjacent molecules attract each other, forming weak connections between them called Van der Waals forces. Van der Waals forces explains two important properties: cohesion, the attraction between like molecules within a substance, and adhesion, the attraction between unlike molecules in different substances. An example of cohesion is when opposite poles of water molecules are attracted to each other but not to the surrounding air. This creates an inward force allowing water to bead up and form water droplets. Adhesion, the force of attraction between unlike molecules, explains how geckos are able to climb on slick, flat surfaces. Although each molecular connection is very weak, geckos can form millions of them between the molecules within the microscopic hairs on each foot and the molecules in the climbing surface. These connections add up to more than enough adhesion force to support the gecko's weight. In summary, Van der Waals forces are forces of attraction between molecules. They are not the same as chemical bonds between atoms within a molecule. They can occur in permanently polar molecules, such as water, and in non-polar molecules when they become briefly polar due to the changing positions of electrons. A hydrogen bond is a strong Van der Waals force between a polar molecule containing hydrogen atoms and the negative pole of another polar molecule. Van der Waals forces account for cohesion, the attraction between like molecules within a substance, and adhesion, the attraction between unlike molecules in different substances. ♪ [music] ♪

YOU MAY ALSO WANT TO REVIEW THESE ITEMS:
Breast Cysts
Breast Cysts - si1587
Medical Illustration
Add to my lightbox
Find More Like This
Hip Replacement
Hip Replacement - si1646
Medical Illustration
Add to my lightbox
Find More Like This
Complete Surgical Procedure for Spinal Condition
Complete Surgical Procedure for Spinal Condition - exh40974a
Medical Exhibit
Add to my lightbox
Find More Like This
Normal Abdominal Anatomy
Normal Abdominal Anatomy - exh52467a
Medical Exhibit
Add to my lightbox
Find More Like This
Positioning a Child on a Backboard
Positioning a Child on a Backboard - ANS00273
Medical Animation
Add to my lightbox
Find More Like This
Closed Fracture Fixation of Radius
Closed Fracture Fixation of Radius - GX00041
Medical Illustration
Add to my lightbox
Find More Like This
What attorneys say about MLA and The Doe Report:
"This past year, your company prepared three medical illustrations for our cases; two in which we received six figure awards; one in which we received a substantial seven figure award. I believe in large part, the amounts obtained were due to the vivid illustrations of my clients' injuries and the impact on the finder of fact."

Donald W. Marcari
Marcari Russotto & Spencer, P.C.
Chesapeake, VA
"I have found that the personalized medical illustrations prepared by Medical Legal Art have been very accurate and helpful. The medical doctors, both treating physicians and expert witnesses, have commented on the accuracy and professionalism of the medical illustrations. Most importantly, your prompt service and attention upon even short notice has been tremendous. I can certainly say that the medical illustrations prepared by Medical Legal Art have assisted us in bringing cases to a successful resolution."

Paul L. Redfearn
The Redfearn Law Firm, P.C.
Kansas City, MO

"A few words about The Doe Report: recently in a brachial plexus injury case, we used an image from The Doe Report to demonstrate the injury. We downloaded the PDF file image, and were amazed at the quality. The hard copies that you sent were even more clear. As well, we could not have been happier when you customized the image and reversed the injury from the left shoulder to the right shoulder, which is where our client's injury was.

The speed and cost-effectiveness of the product made it the perfect tool for our purposes. We will use The Doe Report again in future cases."

Andrew Needle
Needle Gallagher & Ellenberg, P.A.
Miami, FL

"I wanted to take some time out to let you know what a wonderful job you did with the 'collapsed lung/fractured rib' illustrations. They were both detailed and accurate. My medical expert was comfortable working with them and he spent at least an hour explaining to the jury the anatomy of the lungs, the ribs and the injuries depicted in the illustrations. Needless to say, the jury was riveted to the doctor during his testimony.

The jury returned a verdict for $800,000.00 and I'm sure we would not have done so well if not for the visualizations we were able to put forth with your assistance. Lastly, my special thanks to Alice [Senior Medical Illustrator] who stayed late on Friday night and patiently dealt with my last minute revisions."

Daniel J. Costello
Proner & Proner
New York, NY

Medical Legal Blog |Find a Lawyer | Hospital Marketing