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
 
8/10/20
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:
Impingement Syndrome of the Left Shoulder with Surgery
Impingement Syndrome of the Left Shoulder with Surgery - exh5366a
Medical Exhibit
Add to my lightbox
Find More Like This
Bladder
Bladder - BJ00009
Medical Illustration
Add to my lightbox
Find More Like This
Lumbar Spine Injuries
Lumbar Spine Injuries - exh46075a
Medical Exhibit
Add to my lightbox
Find More Like This
Lysing of Abdominal Adhesions
Lysing of Abdominal Adhesions - exh57875a
Medical Exhibit
Add to my lightbox
Find More Like This
Left Hip Injuries
Left Hip Injuries - exh67417
Medical Exhibit
Add to my lightbox
Find More Like This
Left Foot Fractures with Surgical Fixation
Left Foot Fractures with Surgical Fixation - exh73613a
Medical Exhibit
Add to my lightbox
Find More Like This
What attorneys say about MLA and The Doe Report:
"I wanted to thank you for the terrific job you did illustrating my client's injuries. The case was settled at the pre-suit mediation, and I believe a good part of the success we had was due to the medical legal art you prepared.

Your work received the ultimate compliment at the conclusion of the mediation. The hospital risk manager took the exhibit with them at the conclusion of mediation, and will be using it to train nurses on how to prevent bed sores..."

Steven G. Koeppel
Troy, Yeslow & Koeppel, P.A.
Fort Myers, FL

"For us, the defining feature of effective demonstrative evidence is whether, by itself, the piece will tell the story of the case. Medical legal Art provides our firm with illustrations and animations that are clear and persuasive. Their exhibits tell the story in a way that allows the jury to understand a very complex subject, very quickly."

James D. Horwitz
Koskoff, Koskoff & Bieder, P.C.
Bridgeport, CT

"There is nothing like a great graphic depicting the real nature and extent of a victim's injuries to get full value for your client. I use Medical Legal Art for mediations as well as trial."

Geoff Wells
Greene, Broillet, Panish & Wheeler
Santa Monica, CA

"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
Medical Legal Blog |Find a Lawyer | Hospital Marketing