Why is the Ocean Salty?

Ah...the beach. We recently returned from a trip to the coast of North Carolina where we enjoyed four days of sun, surf, and SALT. I have always been amazed by this unique property of ocean water. You can smell the salt before you step foot on the beach. After a refreshing dip in the ocean you are left with a grainy texture all over as you dry off in the sun. By the time you leave the beach the salt is on your skin, in your hair, and there is even a fine layer over your sunglasses. Where does all of this salt come from?

When I was young I heard an old folk tale about a magic salt mill at the bottom of the ocean. I don’t think this is the answer.

This is a common question but a good one. Rain isn’t salty, rivers and streams that dump out into the ocean aren’t salty either. So why is the ocean salty?

The answer to this question starts with the formation of the earth. Gases containing salt were released from below the earth’s surface into the ocean water. Ever since then, salt is continually dumped into the ocean from rivers. Wait, rivers aren’t salty, are they? Yes, rivers do in fact contain a small amount of salt, just not enough to taste. The salt comes from eroding rock, soil and other organic sources that the river picks up on its journey to the ocean. All the rivers of the world dump into the ocean, the river water evaporates, and the salt is left behind. Here is a diagram illustrating this concept:

http://www.palomar.edu/oceanography/salty_ocean.htm

How much salt is in the ocean? One cubic foot of ocean water will yield over two pounds of salt. All of the ocean salt could cover the entire earth’s surface, 40 stories high!

Ok, I understand now why the ocean is so salty. Salt has been washed into the ocean since the formation of earth. Since salt doesn’t evaporate, will the ocean eventually fill up with salt? Some scientists claim that the ocean’s salt content is higher now than millions of years ago. I imagine there would need to be a major shift in the hydrologic cycle before the amount of salt would exceed the amount of water in the ocean.

Some areas of the earth have higher salt concentrations than others. The Arctic is less salty with the presence of melting glaciers, and the Persian Gulf has the saltiest water due to higher rates of evaporation.

Salt is present all over the earth, but thanks to the rivers, salt is washed into the ocean where it is left for us to enjoy. The salty air, the gritty film on your sunglasses, even the mouthful of salt water you get when surprised by a wave, all adds up to a great vacation.

Experiment:
You can show your children how salt is left behind in the ocean by doing the simple evaporation experiment described at the bottom of the page at the following link:
http://wondertime.go.com/learning/article/0806-why-the-ocean-is-salty.html 

Sources:
http://www.palomar.edu/oceanography/salty_ocean.htm
http://wondertime.go.com/learning/article/0806-why-the-ocean-is-salty.html

Sugar Momma

     Sugar is something all moms have in mind. We make sure our children don’t have too much sugar, and even indulge in it ourselves for that late afternoon pick-me-up. Who hasn’t raided their children’s leftover Easter or Halloween candy? Like many moms I ration sweets out to my children on occasion. For them there is a weekly sugar payload at the supermarket. After a trip to the deli, they get a free kid’s club cookie at the bakery, usually a sugar cookie. When the cookies happen to have sprinkles, my daughter declares, “It’s our lucky day!” After check out they also gleefully approach the bank counter and get a lollipop for the ride home. One sugar cookie and one lollipop is well worth getting a weeks worth of groceries in peace.
    I also have the secret stash of dum dums for those important times when I really need the girls to, say, pose for a family photo. Yes, bribe candy.
    All sweets share the same main ingredient: sugar. But what makes lollipops hard, gum drops soft, and taffy so chewy? I decided to find out.

What is Sugar?
    To know candy, one must know sugar. The Science of Cooking website provides a great explanation and diagram:

“The white stuff we know as sugar is sucrose, a molecule composed of 12 atoms of carbon, 22 atoms of hydrogen, and 11 atoms of oxygen (C12H22O11). Like all compounds made from these three elements, sugar is a carbohydrate. It’s found naturally in most plants, but especially in sugarcane and sugar beets—hence their names.

Sucrose is actually two simpler sugars stuck together: fructose and glucose. In recipes, a little bit of acid (for example, some lemon juice or cream of tartar) will cause sucrose to break down into these two components. 

If you look closely at dry sugar, you’ll notice it comes in little cubelike shapes. These are sugar crystals, orderly arrangements of sucrose molecules.”

How Does Sugar Become Candy?

    Simply speaking, candy is made by dissolving sugar in water, then cooking the sugar solution to a particular temperature until the desired consistency is reached. As the temperature rises, so does the sugar concentration as the water evaporates. A high concentration of sugar will result in a hard candy such as lollipops and brittle, and lower concentrations of sugar cooked at lower temperatures will produce candy such as jellybeans and gumdrops. Here is a little chart to help illustrate the process:

                  Stage                    Temperature in °F               Sugar concentration

thread                               230-233°F                                80%

soft ball (e.g., fudge)        234-240°F                                85%

firm ball                            244-248°F                                87%

hard ball                           250-266°F                                92%

soft crack                         270-290°F                                95%

hard crack (e.g., toffee)   295-310°F                                99%

clear liquid                       320°F                                      100%

brown liquid (caramel)     338°F                                      100%

burnt sugar                      350°F                                      100%

                        Source: http://en.wikipedia.org/wiki/Candy

The “Stage” describes the consistency of the sugar solution when a sample is dropped in cold water, a.k.a. The Cold Water Test. Notice that as the temperature rises, so does the concentration of sugar and the firmness of the resulting candy. 

    So the answer to my question is quite simple: heat. Various temperatures create various textures of candy. A quick search of candy recipes will reveal other ingredients such as corn syrup and cream of tartar. These ingredients prevent the sugar from crystallizing in recipes such as lollipops, when you want a clear, glass-like candy. Some softer candies, such as toffee, use butter to prevent grainy crystals from forming and help maintain a smooth texture.

Click Here for the recipe for rock candy. This is a great and tasty experiment about saturated solutions.

New Baby Smell

It’s the first thing people say when they hold a newborn baby. “Oh, I love that new baby smell!” All newborns seem to be born with that sweet scent, one that fades much too soon. I can remember snuggling with my daughters when they were first born and they, too, had the New Baby Smell.

    So what causes the New Baby Smell, what purpose does it serve, and why is it so short-lived? My initial guess is that the scent serves some kind of evolutionary purpose, that it helps mothers and infants attract to one another to ensure the infant’s survival. So I set out in search of some answers. 

    Much to my surprise, I was unable to find any scientific research on this topic, at least not any that is readily available. I searched and searched, but was only able to find theories that others have posted online.

    Below are some of the more popular theories about how and why newborns have that New Baby Smell. Please leave a comment if you have any more information to share on this topic!

   Theory #1 (and my best guess): The sweet smell of a newborn encourages the mother to hold, protect, and feed the baby. Newborns are completely helpless at birth and depend on their mothers for survival. There is plenty of scientific evidence that newborns have the ability to recognize their mothers’ scent and thus find the food source, milk. The newborn has done it’s part, and the lovely scent of the infant helps the mother to do her part, nurture the baby. From my experience, the smell seems to come from the top of infants’ heads. When you smell the head of a baby, they are cradled in your arms, protected.

    Theory #2: The smell is not from the baby, but rather the smell of the perfumed baby lotion, soap, powder, and laundry detergent. It is true that all those products smell great and make one smell like a baby. However there are plenty of people out there who don’t use perfumed products and claim the New Baby Smell is still there. I personally think there is a difference between New Baby Smell and the scented baby products.

    Theory #3: The smell is actually that of breastmilk. Many people claim that the New Baby Smell seems to fade around the time when babies wean, or start eating solid food, so it must have something to do with being breastfed. Infants are attracted to the scent of their mother’s milk, so it makes sense that we may like the smell as well. It lingers on the baby’s mouth and on their breath.

    Theory #4: There is no smell, we are just euphoric at the sight of a newborn and instinct tells us to hold and snuggle the baby until someone looks at us like we have lost our mind and we must then put the baby down.

    Again, I believe that there is a New Baby Smell, for I have smelt it. I believe it’s Mother Nature’s way of helping the mother and child form an important bond for survival. If you have another theory or know where to find some scientific research on this topic, please share it with us!

*Photo by Jennifer Kolb Photography

Experiment Idea: If you have a newborn handy, give the baby a good whiff! Try it with and without the baby products and let us know what you discover.

If you don’t have a newborn, ask your children what their favorite scents are, and try to gather some to smell. Some suggestions are flowers, freshly baked cookies, fresh-cut grass, or their favorite dinner.

The Tainted Doughnut

After a very successful morning at mass with 2 preschoolers, my husband and I treated the girls to some doughnuts on the way home. You have to reward that good behavior, right? My 4-year-old of course chose the vanilla frosted doughnut with sprinkles. She licked off all the frosting and sprinkles then declared, “I’m done.” She does this with cakes and cupcakes, too. All frosting. So, I picked up the doughnut and took a bite. My husband nearly gagged and turned away in absolute disgust.

“What?”, I said. “This is a perfectly delicious Dunkin’ Doughnut. I’m not going to throw it away.” He replied, “But it’s saliva.”

Saliva? Please. When you are a mom, a little saliva is nothing compared to the other exciting things that come our way. We have been pooped on, thrown up on, and our precious toddlers come to us and say, “Here Mommy!” and hand us their boogers. I figure that since my daughters and I once shared the same blood, a little saliva on a doughnut is nothing to worry about.

So I decided to find out what exactly is saliva, and, as long as my children are not sick, whether I can indulge in that delicious doughnut after the frosting has been licked off.

What is Saliva?

Saliva is a liquid excreted from 3 different pairs of salivary glands in our mouths. These glands are called the parotid, the submandibular and the sublingual glands. Here is a diagram:

Over the course of one day, the salivary glands excrete between 1 and 2 liters of saliva each day. About 98% of saliva is water, but the remaining 2% contains critical components that help us taste, digest, and protect us from bacteria.

How does saliva help me to taste, for example, a fresh doughnut?  In order for our taste buds to detect flavor, the chemicals in foods must first be dissolved by saliva. You will not be able to taste much with a dry mouth (try the experiment below).

Saliva contains several enzymes, such as amylase, which start the digestive process by breaking down the foods we eat. Other enzymes are antibacterial, such as lysozyme. They help to prevent infection and keep our mouths clean.

If you are one of those mothers who endured morning sickness (or 24-7 sickness in my case), there is a reason our mouths salivate right before that dreaded moment. The saliva helps to protect our mouth from the acids coming up from our stomach.

So, after doing some research, I could not find one good reason to throw out the doughnut my daughter had licked. Again, if my daughter had been sick, I would have tossed it. Plenty of illnesses are transferred through saliva. But now I know that saliva is mostly water, and the other components speed up digestion. As far as I’m concerned, my daughter helped me eat the doughnut.

In the future I may pass on other foods that have been licked. But doughnuts? Those are mighty tasty.

Click here for an experiment on saliva and taste.

Sources:

http://digestivesystem.suite101.com/article.cfm/the_many_purposes_of_saliva

http://www.wisegeek.com/what-is-the-purpose-of-saliva.htm

http://kidshealth.org/kid/closet/experiments/experiment_saliva.html

Bleach And “Washable” Paint

As you all know by now motherhood comes with a lot of laundry. Who knew such small people could create massive piles of dirty clothes? My least favorite is what I call The Stain Wash: clothes that had extraordinary encounters with ink, blood, and who knows what else.

This week I found myself battling the stain of all stains, washable brown paint. Yes, I said washable. My daughter came home from preschool with it on her dress. I thought “it will come right out, it’s washable!” Wrong.

The paint held on through the first wash, and resisted Oxiclean’s oxygen action. I then tried my grandmother’s old stand-by, Fels Naptha bar soap. This gets out just about everything. No luck. Then I tried Clorox Bleach Pen (it is a white dress with black dots). The stain was still there. 

Eliminating this stain had become my new mission. I decided to put full-strength straight bleach on the stain, applying it with a small paintbrush hoping to avoid discoloring the black dots. The results are in the photo below.

Even bleach failed to conquer the washable brown paint stain. I had always believed bleach to be the be-all-and-end-all of stain removal. This got me thinking...what exactly is bleach, how does it work, and why didn’t it work this time? I found the following explanation helpful:

Ordinary table salt (sodium chloride, NaCl) is half chlorine, and a simple electrochemical reaction with salt water produces chlorine gas easily. That same reaction produces sodium hydroxide (NaOH), and by mixing chlorine gas with sodium hydroxide you create sodium hypochlorite (NaOCl). When you buy a gallon of bleach at the grocery store, what you are buying is the chemical sodium hypochlorite mixed with water in a 5.25-percent solution. You're buying salt water that has been changed slightly by electricity.

Chlorine also makes a great stain remover, but not because of the chlorine itself. Natural stains (as well as dyes) produced by everything from mildew to grass come from chemical compounds called chromophores. Chromophores can absorb light at specific wavelengths and therefore cause colors. When chlorine reacts with water, it produces hydrochloric acid and atomic oxygen. The oxygen reacts easily with the chromophores to eliminate the portion of its structure that causes the color. (howstuffworks.com)

Aha! So a chemical reaction changes the molecular structure of the chromophores, inhibiting their ability to produce color. Now I understand how bleach works. But why didn’t it work on the dress? Dr. Laundry does not recommend using bleach on spandex, and my daughter’s dress was a cotton-spandex blend. Maybe that small percentage of spandex was enough to keep the bleach from being 100% effective.

So, the next time you turn to bleach to salvage that outfit you just bought, you will have a little more insight into how it is working...or isn’t.

As for the fate of the dress? I decided to live with the light stain that is left on the back, and I filled in the discolored black circles with a Sharpie. 

If you would like to share some science with your kids, click here for an experiment about separating colors.