What Am I? A featured mystery object of the month Print a What Am I? sign. Add a "clue" in the textbox, print, and post on your bulletin board. Post a different clue every day or so and see who can identify the mystery item. Then plan a "What Am I?" discussion and other related activities. Do you know what I am? Here are some clues: 1. No one really knows exactly when people started using me, but we do know that I was mentioned as far back as Plato s ancient Greek writings. 2. I was probably first used in the Mediterranean area of Europe. 3. My design is based on a real animal that lives underwater and that has been harvested for centuries. I was developed to protect that animal from overfishing. 4. Today, you don t have to go underwater to find me; I can be purchased in most grocery or convenience stores. 5. I am very flexible. 6. Early Europeans used me to pad their helmets. 7. I have also been used as a portable drinking device. 8. I can be very soft or very rough, depending on how I am made. 9. I am most commonly made of cellulose, a fibrous compound found in plants and wood pulp. 10. When squeezed, I can compress down to about one-third my normal size. 11. I come in many different varieties, and some are made of materials such as melamine or metal. 12. I am often used in painting jobs. 13. I am very light and have many holes. 14. The size of my holes helps determine the job for which I am best suited. ActivityConnection.com - What Am I? - June 2013 - Page 1 of 5
15. I am a common household item, usually found in the kitchen. 16. Though I can be used dry for some jobs, I am most often used with water. 17. Automobile enthusiasts love using me to wash their cars because I will not scratch the paint job. 18. I am very absorbent and can be used to clean all kinds of messes. 19. You can use me to do your dishes or while bathing. 20. Hopefully by now, you have soaked up enough clues to be able to guess what I am. Can you guess what I am? If you have been able to absorb my clues, then you know I am a sponge! Print a copy of the pictures to pass around as you share and discuss the information in the article with your group. The sponge is a common household item that you probably use every day, but have you ever wondered where it came from, how it works, or how it is made? Let s take a closer look and soak up some facts about this hardworking cleaning marvel. From the Sea to Your Sink Long before sponges made the move to our homes, their permanent residence was in the ocean. Sea sponges are usually found near colorful coral reefs, preferring quiet waters in tropical zones. They are invertebrates, which means they do not have a backbone. Rather than eating and digesting food, they rely on the water that flows through their porous bodies to bring them food and oxygen and to flush out any waste. The part of the sea sponge that you can see and touch is actually its skeleton. Since ancient times, humans have harvested the absorbent and flexible skeletons of the sea sponge and used them for a variety of purposes. Early Europeans sometimes used the pliable sponges as padding for helmets, and they were even used as water filters. Unsurprisingly, the sponge was most commonly used for cleaning, bathing, and carrying drinking water. As the ActivityConnection.com - What Am I? - June 2013 - Page 2 of 5
demand for sponges increased, divers combed the waters of the Mediterranean for more of these popular little organisms, and by the mid-20th century, the supply had almost been exhausted. Overfishing had nearly driven the sponges to extinction, and the sponge-diving industry suffered because of it. Divers moved to Florida s west coast to continue harvesting sea sponges, and this time they were more careful not to overfish. Meanwhile, scientists began looking for ways to create objects with a sponge-like texture so people could continue using them while giving the sea sponges time to recover. Most of the sponges commonly used today are synthetic, though natural sea sponges are still sold for uses such as painting, hanging wall paper, and washing cars. The sponge in your kitchen is most likely a synthetic sponge, made from cellulose wood fibers, plastics, or polyester. Discussion Questions Sea sponges are not the only underwater invertebrates. Can you think of any others? (e.g., octopus, starfish, jellyfish, clams, crabs, snails, etc.) How do you think overfishing of the sea sponge could negatively affect other underwater critters? (For example, some species of hermit crabs take shelter inside sea sponges.) Choosing the Right Sponge for the Job In this day and age, synthetic sponges reign supreme. Many different kinds have been developed, all with a wide variety of materials and uses. Let s take a look at the different kinds of sponges out there. Cellulose sponges: Cellulose can be found in plants as well as wood pulp and cotton. While cellulose is used to make cardboard and paper, it is also a very absorbent compound, making it ideal for sponges. Melamine sponges: In the 1830s, a German chemist named Justus von Liebig synthesized this material using carbon, nitrogen, and hydrogen. Melamine sponges are especially good at removing tough stains and marks made by crayons, markers, grease, ink, soap scum, and scuffing. Dry sponges: Though these sponges are also made from cellulose, they are very different from the generic cellulose sponge. Dry sponges are to be used on surfaces that cannot get wet, such as lamp shades or wallpaper. While a wet cloth or sponge would smear dust, pet hair, soot, and smoke, dry sponges simply absorb these fine, dry substances. Abrasive sponges: Sponges made from metal and nylon have a very rough texture and are prime candidates for a job that requires a lot of scrubbing. Loofah sponges: Loofah (or luffa) sponges are made of the fibrous cellulose found in the luffa gourd, native to tropical parts of Asia and Africa. The most common uses for loofahs are bathing and showering as well as washing cars and boats. ActivityConnection.com - What Am I? - June 2013 - Page 3 of 5
Can You Guess? 1. Which absorbs water better: a dry sponge or a wet sponge? Though you might not think so, a sponge that is already slightly wet will absorb water more quickly and hold onto it better than a dry sponge will. This is because water molecules are very attracted to each other, and the water molecules on a surface will quickly try to bind with the water molecules already in the sponge. 2. How did ancient sponge divers harvest sponges? Divers were trained from a very young age to hold their breath for long periods of time. This allowed them to dive deep into the ocean. Divers jumped overboard naked (to reduce resistance from the water) and held a weight to help them sink quickly, allowing them more time to cut the sponge loose. Most divers went 100 feet below the surface, staying there for up to five minutes at a time. Today, divers use wetsuits and oxygen tanks. 3. Which sea creature has found a use for the sponge? In 1997, it was discovered that bottlenose dolphins in western Australia attach sponges to their beaks to protect them when scavenging for food at the bottom of the sea. This behavior has not been seen in use by any other dolphins elsewhere in the world. 4. What is unique about the cells in live sponges? Most types of cells within all known living sponges are unspecialized and can move throughout their bodies, allowing the sponge to remold itself and change its shape. Some sponges can even change from one kind of sponge to another. 5. Scientists are studying the use of the sea sponge in the possible treatment of what diseases? Some sea sponges are composed of compounds that could potentially be used to help treat malaria and tuberculosis, and some of those compounds could even combat viruses and cancers. The Holes Make the Sponge The most common type of sponge, the cellulose sponge, is made by mixing wet sheets of cellulose fiber either from plant fibers or wood pulp with sodium crystals in a large container. The mixture is then poured into a mold and heated to melt the sodium crystals out of the sponges. The crystals leave behind holes in the mixture, making the sponge especially porous. Crystals of different sizes can be added to make larger or smaller holes for different uses. The mixture is then dried and cut into the proper size or shape, and then the sponges are packaged for distribution. The size of the holes in a sponge is very important because it determines how porous the sponge will be. Sponges absorb water by taking it in and storing it in its empty spaces, making the sponge swell up. This way, the water stays inside the sponge until it is squeezed, forcing the water back out. If you have ever squeezed a sponge before, you know that it will compress to a much smaller size than ActivityConnection.com - What Am I? - June 2013 - Page 4 of 5
when it is at rest. The holes in the sponge are what allow for that compression and make the sponge flexible and absorbent. Therefore, a sponge with larger holes will hold more water, while sponges with smaller holes will absorb finer substances, such as powders, soot, and makeup. Discussion Questions Earlier, we named many different kinds of sponges. Which kinds of sponges have you used before? What did you use them for? Do the sponges you use have large holes or small holes? How do you think this feature helps them do their job better? ActivityConnection.com - What Am I? - June 2013 - Page 5 of 5