As a member, you'll also get unlimited access to over 79,000 lessons in math, English, science, history, and more. Plus, get practice tests, quizzes, and personalized coaching to help you succeed.
Try it risk-freeAlready registered? Log in here for access
Have you ever heard the phrase 'oil and water don't mix'? Though this phrase is hardly ever used in a scientific setting, the basis behind the old saying is due to chemistry. Indeed, oil does not mix with water and, because of this, it is considered hydrophobic. Let's discuss what it means for a molecule to be hydrophobic, and why this is an important characteristic in chemistry.
The word hydrophobic comes from the Greek roots hydro- (meaning water) and -phobia (meaning fearing or hating). The word hydrophobic describes the fact that nonpolar substances don't combine with water molecules. Let's take a closer look at that definition. Water is a polar molecule, which means that it carries a partial charge between its atoms. Oxygen, as an electronegative atom, draws the electrons of each bond closer to its core, thus creating a more negative charge. Therefore, any materials with a charge, be it negative or positive, will be able to interact with water molecules to dissolve. (Think of how salt dissolves in water. This is due to the charges of the ions sodium and chlorine.)
So essentially, hydrophobic molecules are molecules that do not have a charge, meaning they are non-polar. By lacking a charge, these molecules do not have any charge-to-charge interactions that will allow them to interact with water. Hydrophobic materials often do not dissolve in water or in any solution that contains a largely aqueous (watery) environment. This characteristic of being hydrophobic - or non-polar - is important for many of the molecules found in nature, in other organisms, and even within our own bodies.
Waxes are practical examples of hydrophobic molecules that are used commercially and biologically because of their abilities to resist interacting with water. For example, if you have ever had your car waxed, you probably noticed that the water would bead up and roll off of the paint afterwards. This is because the applied wax is hydrophobic and will not interact with water. Waxes, in this case, help to keep water away from the surface of the car.
 |
On the other hand, in many biological systems, waxes may be used for other means. Some plants, for example, utilize waxes to prevent water from escaping through evaporation. Many of the succulent plants, such as aloe, produce waxes that allow their tissues to retain water for biological use. Still, the reason these plants are able to do so is the hydrophobicity of the waxes.
 |
Many of the key vitamins and hormones in the body are steroids, and these molecules are non-polar. These include testosterone, progesterone, and other hormones that are derived from cholesterol. Additionally, these include vitamins A, D, E, and K, which do not dissolve in water. (Coincidentally, most steroid molecules are soluble in fats and lipids.) This allows steroid hormones and vitamins to last longer within the system, and preserves them for future usage within the body. In addition, the hydrophobic nature of these molecules allow for these molecules to cross the plasma membrane and enter body cells easily.
 |
The word 'hydrophobic' comes from the Greek roots 'hydro' meaning 'water' and 'phobia' meaning 'fearing or hating.' To put it another way, hydrophic describes the fact that nonpolar substances don't combine with water molecules. Water is a polar molecule which means that it carries a partial charge between its atoms. Hydrophobic molecules are molecules that do not have a charge, meaning they're nonpolar. Hydrophobic materials often do not dissolve in water or in any solution that contains a largely aqueous (watery) environment. Oil, waxes, and steroids are all examples of hydrophobic materials and molecules.
 |
| Vocabulary | Definitions |
|---|---|
| Hydrophobic | hydro (water) and phobia (fearing or hating): nonpolar substances don't combine with water molecules |
| Polar molecule | water carries a partial charge between its atoms |
| Hydrophobic molecules | molecules that are nonpolar or do not have a charge |
| Aqueous | watery environment |
Examine the video lesson on hydrophilic molecules closely so that you can later:
To unlock this lesson you must be a Study.com Member.
Create your account
Already a member? Log In
BackAlready registered? Log in here for access
Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.
To learn more, visit our Earning Credit Page
Not sure what college you want to attend yet? Study.com has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.
Back To Course
Anatomy & Physiology: Tutoring Solution19 chapters | 330 lessons
{{courseNav.course.topics.length}} chapters | {{courseNav.course.mDynamicIntFields.lessonCount}} lessons | {{course.flashcardSetCount}} flashcard set{{course.flashcardSetCoun > 1 ? 's' : ''}}
Your Cart is Empty. Please Choose a Product.
Watch 5 minute video clips, get step by step explanations, take practice quizzes and tests to master any topic.
Study.com has a library of 550,000 questions and answers for covering your toughest textbook problems
I love the way expert tutors clearly explains the answers to my homework questions. Keep up the good work!
- Maritess, College StudentStudy.com video lessons have helped over 30 million students.
"I learned more in 10 minutes than 1 month of chemistry classes"
- Ashlee P.
"I learned more in 10 minutes than 1 month of chemistry classes"
- Ashlee P.
"I aced the CLEP exam and earned 3 college credits!"
- Clair S.
Over 65 million users have prepared for {{displayNameByProductKey[registrationData.product || testPrepCocoon]}} and other exams on Study.com
"The videos have changed the way I teach! The videos on Study.com accomplish in 5 minutes what would take me an entire class."
- Chris F.
Over 65 million users have prepared for {{displayNameByProductKey[registrationData.product || testPrepCocoon]}} and other exams on Study.com
Over 65 million users have prepared for {{displayNameByProductKey[registrationData.product || testPrepCocoon]}} and other exams on Study.com
