How Was Ice Cream Developed?

You know your favorite flavor and that you have to eat it fast before it melts, but do you know the science of ice cream? Believe it or not, ice cream as we know it has had a pretty rocky road in order to be as yummy and available as it is today. In "The History of Ice Cream," written by the International Association of Ice Cream Manufacturers (IAICM), Washington DC, 1978, a very detailed history of the cold and creamy treat is described. The funny part about the book, though is that most of the early history of ice cream remains unproven folklore.

And so the story goes...once upon a time, hundreds of years ago, Charles I of England hosted a banquet for many of his friends and family. The meal featured the greatest foods of the day and ended with a cold treat that resembled fresh-fallen snow. The guests as well as Charles loved the cold treat and Charles paid the cook 500 pounds a year to only serve it at his Royal table. The cook kept the secret until Charles was beheaded in 1649.

This tale along with others provides some insight into the evolution of our country's most popular dessert. Most likely, ice cream was not invented, but rather came to be over years of similar efforts. Even the Roman Emperor Caesar is said to have sent slaves to the mountains to bring snow and ice to cool and freeze the fruit drinks he was so fond of. Centuries later, the Italian Marco Polo returned from his famous journey to the Far East with a recipe for making water ices resembling modern day sherbets.

These tales are interesting and help to connect history with food science as well as cultural traditions. Unfortunately, no real historical evidence supports any of these stories. The tales might just have been a marketing plan of the nineteenth-century ice-cream makers and vendors. When it comes to actual facts, it seems that ice cream may have had its first appearance in China.

Although the actual history of ice cream is rocky, some of the inventions that were made to improve ice cream are a little more know. The first improvement in the manufacture of ice cream (from the handmade way in a large bowl) was given to us by a New Jersey woman, Nancy Johnson. In 1846, she invented the hand-cranked freezer. This device is still familiar to many. By turning the freezer handle, they agitated a container of ice cream mix in a bed of salt and ice until the mix was frozen. Because Nancy Johnson lacked the foresight to have her invention patented, her name does not appear on the patent records. A similar type of freezer was, however, patented on May 30, 1848, by a Mr. Young who at least had the courtesy to call it the "Johnson Patent Ice Cream Freezer." Commercial production was begun in North America in Baltimore, Maryland, 1851, by Mr. Jacob Fussell, now known as the father of the American ice cream industry. Right in our backyard at Penn State, tremendous research on how to make ice cream from making the best flavors to extending its shelf-life have been occurring for decades. Besides several tasty flavors, the Penn State Creamery offers a course (Ben and Jerry even took it) and a little museum. Maybe one day this summer when you are hot and in the mood for a sweet taste and a food science lesson you should ask your parents to take you down 322 E to Happy Valley. In the meantime, share your secrets on ice cream to your friends and family.

Little Lions Experiment:

Fill up a paper Dixie cup with water and another one with fruit juice. Only fill up the cups to about 3/4 full as liquid expands as it freezes (molecules in ice are bigger than they are in a liquid state). Then, place them carefully in the freezer and time how long they take to freeze. Monitor the process and see where ice forms first. Try to think why ice forms on the top before in the middle. Then, time to see which freezes first water or fruit juice. You can freeze other liquids such as milk or solids just as pudding or yogurt, if you want. Try to determine if a substance's state (liquid or solid) affects its freezing time as well as the material's density, i.e. has more sugar, food ingredients in it. Then, enjoy your frozen treats. Be careful, not to give yourself a "brain-freeze" as cold foods can cause mild nerve triggers that can hurt your head.

How Do Firecrackers Work?

I am sure by this time of you most of you have seen, heard and even fired firecrackers. But, do any of you know what makes firecrackers crack, bang, and light up? If not, I will explain it to you. It is actually quite simple--it's science.

Today's firecrackers use gunpowder. But, firecrackers came long before gunpowder. The actually date centuries across to China. In fact, the firecrackers were entirely natural or organic. They were probably an accident, too. It is said that these early firecrackers came about because someone tending a fire ran short of fuel and decided to throw in a few lengths of green bamboo. Bamboo is a type of plant. The bamboo, knobby round reeds, would blacken, smoldered, and hissed. Surprisingly, they would end up exploding. How did this happen?

The answer is that inside bamboos are pockets of air and sap. These pockets, when weakened by the fire, will expand and eventually burst. The result is a sharp reverberating bang. Back then, this never-before-heard noise was quite alarming.

The Chinese figured that if this noise scared them it would scare evil spirits. One particular evil spirit was Nian. This spirit was known to eat crops and people! To protect themselves, the Chinese would use "bursting bamboo" or pao chuk at all special ceremonies such as weddings and celebrations for centuries.

Soon, a Chinese chemist accidentally discovered gunpowder. This chemist was mixing around sulfur, charcoal and potassium nitrate (KNO3) and BANG! This bang was more powerful and louder than ever!

Over time, the Chinese used chemistry to perfect their firecrackers. They also used this knowledge to do more than just scare evil spirits. They used firecrackers and extensions of them---rockets and bombs---to blow away their enemy.

Luckily, many scientists have stayed true to making firecrackers fun! These scientists have found that certain chemicals make the firecrackers colorful. And, potassium chloride (KClO3) was found to be even better than KNO3 as it made the colors deeper and brighter. Example chemicals that make certain colors are strontium to make red, barium to make green, copper to make blue, and sodium to make yellow.

Little Lion Experiment:

How to make safe firecrackers:

Materials:

• Toilet paper or paper towel rolls
• Dry rice or dry beans
• Colorful wrapping paper
• Curling ribbon

Steps:

Cover the cardboard rolls with wrapping paper. Leave about 3 inches of excess paper on each end. Gently twist wrapping paper to close ends. Secure the ends of the wrapping paper with ribbon. Before securing last end, put a few dried beans or rice inside. Shake the roll. It will make noise like a "firecracker."

Why do the Seasons Change?

When does summer actually start? Do you think summer starts as soon as school ends? Or, do you think it starts as soon as the sun is out and burns your skin? The last day of school, sunny days and sunburns are all signs of summer. But, in the northern hemisphere (the top half of the globe), summer does not actually start until June 21st.

To be exact, summer starts at 0148 UT on June 21st, which is 9:48 Eastern Standard Time (our time zone) on June 20th. Yes, that means summer actually starts during the night of the 20th for us. But, June 21st is still the first full day of summer. Known as the summer solstice (sun stands still), June 21st is the longest day of the year.

In the southern hemisphere, below the equator (the line in the middle of the globe that splits the world into two), winter arrives. For them, June 21st will be the shortest day of the year. It also marks the start of winter for them.

Why do the weather and seasons change? To answer this question we have to think about the planet we live on. The Earth takes a yearly trip around the Sun. For part of the year, the Earth's north pole points away from the Sun and part of the time toward it. When the North Pole points toward the Sun, the Sun's rays hit the northern half of the world more directly and it is summer. But when the North Pole is pointed toward the Sun, the South Pole is pointed away. So the Sun's light hits the Earth at a less direct angle, spreading the warmth over a larger area, and it is winter.

Some people think the seasons are caused by how far the Earth is from the Sun. But, the Earth's orbit about the Sun is very close to circular and the distance of the Earth from the Sun only differs by about 3% during the year. Another problem with this hypothesis is we are actually closest to the Sun on about January 2nd, and the farthest on about July 4th. This is the opposite of hot and cold weather in the northern hemisphere. Therefore, the angle at which sunlight hits the Earth is more of a cause of seasonal changes than the Sun's difference from Earth.

Another factor in seasonal changes is the length of days and nights. In the summer, daylight lasts longer and nighttime is shorter. This makes the temperature higher. In winter, the days are shorter and the nights longer. The winter gives the sun little time to warm up the Earth so short winter days do have long, cold nights.

Speaking of winter, the shortest day is the first day of winter. For us in the north, it is around December 21st or 22nd. This day is known as the winter solstice.

Between winter and summer, we have spring. It starts on about March 20th. On this day, day and night time are each 12 hours long. This is called the vernal equinox. It is the first day of spring north of the equator and the first day of autumn in the southern half of the world.

In between summer and winter there is another equinox, called the autumnal equinox. Just like the vernal equinox, day and night each are 12 hours long. But, it is now the first day of autumn north of the equator and the start of spring to the south.

What Is In Sweat?

Now that springtime has finally arrived, so has the Sun. More Sun means higher temperatures and more time to spend outside playing. Oftentimes, Sun, heat and sports equal sweat. I am sure most of you have experienced this but do any of you know why this occurs? Do any of you know what sweat exactly is? If not, read this.

Sweat or perspiration is the fluid produced by sweat glands. Sweat glands are found mainly in the skin of the armpit. But, other areas on the body produce sweat. This would include your forehead, hands and feet.

But, what is it made of? Sweat is a mixture of water, ions, urea, uric acid, amino acid, ammonia, glucose, lactic acid and ascorbic acid. What are all these things? Water is just that---water. Ions include sodium, which is represented by the chemical symbol Na+ and chloride, which is represented as Cl-. These are often thought of as together as salt. They help to make our sweat so sticky and "salty."

These important ions are taken away from the body when they are "sweated out." When an athlete exercises for several hours in the hot sun, they lose lots of sodium and chloride and other types of electrolytes. Electrolytes are any compound that separates into ions when dissolved into water and is able to conduct electricity. They are very important to helping us stay hydrated or with enough water to function. A water loss of as little as three percent hurts our ability to run, walk and think. When we sweat a lot, we lose lot of electrolytes. This is why products such as Gatorade were created. They provide athletes, who sweat a lot during workouts and games, with much needed water and electrolytes.

Okay, so we know what electrolytes are. What about all those other things in sweat? Urea, amino acid and ammonia are products that are made from the break down of protein. Protein is found in foods such as meat, fish, eggs and milk. Proteins serve many roles in the body: they help us grow, help with chemical reactions in the body, help control body processes through hormones, help protect the body against foreign invaders through antibodies, help in maintaining hydration, help maintain they body's acid-base balance, transport substances such as oxygen around the body and also provide us with energy to walk, talk and breathe. Proteins are important!

Glucose or "sugar" provides the body with energy too. Lactic acid is produced when we use up our glucose stores in the muscle. It causes the burning feeling in our muscles when we exercise a lot. Ascorbic acid or vitamin C is found in oranges. It helps with many key body functions.

All these important things are in that sticky fluid that runs down our face when we exercise outside when it is hot.

But, why do we sweat? Sweat helps to regulate the body's temperature. It provides a way to cool the body down. It also gets rid of some of the body's waste products such as lactic acid that the body does not need.

Obviously, sweating is important for the body. It is also important to remember when we are outside sweating away to drink plenty of water and, if needed, sports drinks like Gatorade to replace our lost electrolytes.

What Is The Life Cycle Of A Butterfly?

Even wonder where a butterfly comes from or how it grows up? The lifecycle of a butterfly is actually not that simple. Unlike humans who look a lot alike whether they are a newborn baby or great-grandparent, butterflies go through four different life stages. In the beginning or their first stage, an adult butterfly lays an egg. Next, the egg hatches into a caterpillar or larva. You have probably seen many green or furry black and yellow caterpillars crawling around leaves, trees and your fingers in the spring and summer. The caterpillar then changes into a chrysalis (KRIS-uh-liss), which is also called a pupa. A chrysalis or pupa looks like a tiny leathery pouch. This summer look for them under leaves. When the chrysalis matures or grows up, it turns into a butterfly.

Little Lions Experiment:

Make a butterfly!

Materials:

• Toilet-paper tube
• Tongue depressor or ice-cream pop stick
• Heavy paper
• 6" (150 mm) piece of pipe cleaner, folded in half
• Markers or crayons
• Scissors and glue

Steps:

1. Cut out and color a butterfly from the heavy paper. Use any colors, but make both halves look the same. Put a small hole at the top of the butterfly's head.
2. Color the toilet paper tube to look like a chrysalis. (A monarch butterfly's chrysalis is green, but you can use any color.)
3. Take a piece of pipe cleaner and shape it like the letter "V". Put one point through the little hole in the butterfly's head and then twist it to look like antennae. Butterflies use these "feelers" to learn about their environment.
4. Glue the butterfly to one end of the tongue depressor or ice cream pop stick. Let the glue dry.
5. Curl the butterfly's wings and slide it into the chrysalis.
6. Pull the stick to make the beautiful butterfly come out of the chrysalis.

Now that you know all the lifecycles of a butterfly and can even make one, do you want to know how to tell the difference between a butterfly and a moth? If so, this is how you do it: most butterflies hold their wings together over the back when resting. A moth generally holds its wings spread out over its body or curled up tightly around it. Another difference between butterflies and moths is that a butterfly's antennae are generally long, with knobs at the end. On the other hand, a moth's antennae lack knobs, are usually shorter, and may be fuzzy. Go outside and try to dig up, spot and find the butterfly at all four lifecycles. Make sure not to confuse a butterfly with a moth!

How Do Sounds Travel In Space?

Everyone loves movies, they can make us laugh or cry or jump out of our seat! But when it comes to science, movies do not always tell the whole story.

Movies set in space are a great example. Have you ever watched a movie that is set in outer space and heard an explosion? This would never happen in space. As most of us know, space is a vacuum; this means there is a whole bunch of nothing in the air. The air here is made of tiny molecules like oxygen, nitrogen and carbon dioxide. In space, these molecules are few and far between. Sound is a wave, like in the ocean and needs molecules to be carried. So just like ocean waves need molecules of water, sound waves need molecules of air to move and be heard.

We are able to see in space because light travels in a different kind of wave called an electromagnetic wave. Electromagnetic waves do not need molecules to send their wave. Another thing related to light and sound is that they do not travel at the same speed. Sound travels at 760 miles per an hour here on earth. I would like to see Jeff Gordon beat that! In space because there are so many less molecules, it would be much slower. We are not talking slow like a turtle, but slow like going only a foot or two over millions of years. Light travels at 671,080,887 miles per an hour in a vacuum like space. We would see the explosion long before we would hear it. This is the same thing that allows us to see lightning before we hear it.

And just another point about space settings is the ever-present exploding planet or spaceship. Pieces of the planet or spaceship created from exploding objects would have an extremely high initial speed, like on earth, and then continue forever in a strait path through space. Here on earth we have gravity to slow exploding objects, in space there is little or no gravity, so the debris would travel outward in straight lines ideally forever until it impacts with something. These exploding pieces would have about the same energy or force they had at the moment of explosion, so if they impacted a ship or planet, no shield would be able to protect you!

Little Lion Experiment:

Explore physics for yourself! A common physics topic is pressure. Pressure is just the amount of force distributed over the amount of area that force is given. For instance, if you took your finger and pressed it into the arm of your sibling or parent, it would hurt quite a bit. If you used the same amount of strength and pressed into their arm with your entire hand, it would not hurt much at all. Lets try the same thing a different way!

Materials

• Paper Cups
• Big thin book or piece of flat, thin plywood

Steps:

1. Step down on a single cup. What happens?
2. Take the paper cups and lay them in a square a little bigger than the size of the book or plywood. Fill in the square with cups so that the cups are all right next to each other.
3. Place the book or wood on top of the cups.
4. Have your parents help you as you step on top of the book or wood. What happens? Do the cups break as they did when you stepped on just the one?

So what happened is the force (your weight) is distributed over all the cups instead of just one cup. So the cups are able to hold you up! This is the same way a bed of nails works. If you lay on one nail, OUCH! But because your weight is distributed over several nails, it is just a little prickly.

How Does A Basketball Bounce?

Did you ever wonder while you were watching Michael Jordan running up the court, dibbling a basketball and shooting a game-winning final-second shot how a ball bounces?

If so, here is the answer. A basketball bounces because of air and gravity. Air makes the ball bounce because air does not want to stay up. Air wants to go down. It is like that old saying---"what goes up, must come down." This old saying is true and also describes gravity.

Scientific properties of a basketball also help to explain why if you bounce the ball hard, it will go high, But if you make a small bounce, the ball will not bounce much. This is because of elasticity. Elasticity is defined as an object's property of changing shape when the deforming force is removed. A basketball is elastic. So, when it hits a hard surface, the ball's shape is deformed and kinetic energy (energy in motion) is changed to and stored as potential energy (energy that is stored). Once the basketball returns to its original shape, potential energy is changed back into kinetic energy and makes the ball bounce. Based on this scientific principle, pulling a little muscle into your dribbling will help you make the basketball bounce higher.

Air and gravity play important roles in basketball. You have probably noticed how important air is when your ball is deflated or without air. Does a basketball without air bounce? NO! So, you need to keep your basketball filled with air. But, air only supplies a part of the energy storage in an under-inflated basketball. Another player in a basketball's energy supply is the ball's leathery skin. But, the skin does a bad job of storing the energy it gets from being bounced. It is like a leather belt. It is not very elastic. It quickly loses the energy it gets as thermal energy. These scientific properties of a ball make having a well-inflated basketball important.

Science in sports is not limited to how a basketball bounces. The following website provides more details of how science is a key player in the entire game of basketball: http: //www.physics.utoronto.ca/~rbhat/bball/physics/.

Learning more about the science of sports may help you be the Michael Jordan of your basketball team and science class.

Little Lion Experiment:

Materials:

• Different types of balls (basketball, baseball, tennis balls, football, etc.)
• Measuring stick
• Paper and pencil
• Teammate

Procedures:

1. Take one ball at a time and bounce it.
2. Have a teammate use a measuring stick to determine how high that ball bounced.
3. Record the type of ball you bounced and how high it bounced.
4. Figure out which type of ball bounced the highest. Why? (Hint: Remember air and gravity. Shape is also important.)
5. Pick a sport and play it often. Participating in sports is good for your heart and head.

How Do Insects Climb Walls?

Everyone has seen the little critters: they fly around, climb up and down walls, and generally make themselves a big nuisance. It's the housefly, and if you look at them closely you can understand how insects can climb on a wall that no human could. Flies are just like most insects; they have six legs and three sections to their body, a head, a middle section called a thorax, and a hind section that is called the abdomen. Since flies fly, they have wings as well.

But how do they climb on walls? It helps to imagine what it would be like if we were a fly. Let's say we suddenly shrunk down to the size of a fly. Everything would be about 150 times bigger! Suddenly a piece of paper would be around the size of a 12 story building! If we walked over to a wall, we would notice that instead of a smooth surface, it actually looks bumpy and rugged. That's because everything we use, from wood to plastic, has some kind of a roughness to it. But if the roughness is small enough we don't notice it. Since we are still the size of a fly, when we go to the wall we find that it is made up of bumps and crevices about the size of a small doorknob. So if we were the size of flies, with a little effort we could climb walls too. Flies don't have hands, instead they have little hooks at the end of each of their feet. In addition, for smoother surfaces they have little sticky pads which not only help them to walk but act as tastebuds. So everytime a fly walks around, it's tasting what it's walking on! This helps the fly to find food and places to lay its eggs.

There are lots of fun facts about flies and most of them can be found either on the web or at a library near you. The one bad thing about flies (besides being annoying), is that they can carry harmful diseases. The best way to avoid having flies around is to keep everything clean and dry.

Little Lions Experiment:

Now you can see for yourself the ways a fly can walk around on walls, glass, and ceilings. Take a piece of paper and fold it into quarters. This will be your "wall." Arrange the paper so that some of the folds are peaked like mountains and others are down like valleys. This is similar to how a wall would look to a fly. Take something smooth like a ceramic tile or a coaster and place it next to the paper. Now take your pointer finger and make it into the shape of a hook. You now have a fly leg! Drag it across the paper and the tile. Next take a piece of tape and with the sticky side down drag it across the paper and the tile. Which works better on the paper? Which works better on the tile? Why do you think a fly has both?

Why Do You Get Tired After Thanksgiving Dinner?

Ever feel really sleepy after Thanksgiving dinner? Ever watch your grandfather fall fast asleep after eating his Thanksgiving meal? You are not alone. Many people hit the hay after enjoying their Thanksgiving feast featuring everyone's favorite bird - the turkey. Some think that the turkey makes them tired. Is this true?

People think turkey puts them to sleep because it is made up of L-tryptophan. But what is L-tryptophan? L-tryptophan is an amino acid. An amino acid helps to build proteins. Proteins are very important to your body. Along with making up your muscles so you can move, proteins also control the billions of chemical reactions that happen in your cells every day. If these reactions did not take place, you would not be able to make stomach acid to digest your food, produce sweat to cool yourself off in the summer, get oxygen and nutrients from your blood to your cells, fight off infections or do pretty much everything your body needs to do to stay alive.

Proteins are made up of various amino acids, not just L-tryptophan. Humans need to eat nine "essential" amino acids to survive. L-tryptophan is one of these nine. It is a normal and important part of everyone's diet. L-tryptophan is also natural sedative or, in other words, a compound that relaxes people and makes them sleepy. L-tryptophan also helps to make serotonin--a normal chemical in the brain that is also a sedative. Some people actually take L-tryptophan to help them fall asleep. But, in large amounts, it is not healthy and could cause serious problems such as death. As a result, the Food and Drug Administration, the government agency that decides which foods and drugs can be legally sold in the United States, banned it from being sold in this country.

Even though L-tryptophan can help you fall asleep, it is unlikely that the amount in your Thanksgiving turkey is putting you to sleep. This is because L-tryptophan only affects the brain if your stomach is empty and there are no proteins present. Do you plan on eating only turkey for Thanksgiving? What about those delicious food items on your plate such as candy yams and cranberry sauce? And, who can forget about that pumpkin pie? Also, turkey is made up of many proteins, so L-tryptophan would not be alone in your stomach even if you did pass up all the other delicious dishes.

As you can see, if you are tired after turkey, it is probably not the L-tryptophan in your turkey that is making you fall asleep. You are probably just tired from helping your parents cook that great, big meal or from working up an appetite while playing football outside with all your cousins or from simply overeating. Overeating---not just turkey, but mashed potatoes, cranberries, yams, peas, carrots, bread, pies, and whipped cream---demands a lot of blood to be pulled towards your digestive system to help break down all that food. This blood is pulled away from your brain. Your brain constantly needs blood for you to think and be alert. Losing even small amounts can cause you to feel tired. So, if you want to stay awake for desert or to watch the end of The Sound of Music or to see your neighbors start to put up their Christmas decorations, you should probably take your time and enjoy your meal. Don't fill up! And, after that delicious dinner, take a walk or help wash the dishes.

Little Lion Experiment:

Corn was a stable food item for the Indians because it was easy to grow and very nutritious. Try to grow your own!

Materials:

• Kernels of popcorn
• Ziploc bag
• Dirt
• Water

Procedure:

Place a couple handfuls of dirt into your Ziploc bag; add a little water and a few kernels of popcorn. Then, seal the bag and place it in a sunny window. Observe your corn grow. In about a week, your corn should be sprouting

For the advanced scientist, you can make a couple bags of corn and test the effects of different amounts of sunlight, water and air. Be sure to record how much or how little you provided your kernels.

How Should You Clean Earwax?

Have you ever wondered where earwax comes from? Your ear, of course! But where in your ear is earwax made? Earwax, which scientists call cerumen (pronounced suh-ROO-muhn), is made from special glands in your outer ear canal. These glands produce the gloppy substance that we call earwax. The outer ear canal is a tube between that flap of skin on each side of your head that scientists call the auricle, what most people think of as your ears, and your eardrums.

So what does earwax do, exactly? Well, your eardrum is a very sensitive membrane. It's only a few cell layers thick, so it is very important that it stays clean. Earwax protects the eardrum from dust and dirt particles that may irritate it. Dirt particles entering the ear get trapped in the gooey wax and are eventually pushed out of the ear naturally. In a healthy ear, earwax is pushed to the outside of the ear where it eventually flakes off, carrying whatever dirt and grime it has collected with it. Earwax also traps and prevents bacteria from growing in the ear canal, helping to prevent ear infections.

So how do you clean the earwax from inside your ear? You don't! Never stick anything smaller than your elbow in your ear canal! Earwax helps to prevent harmful substances like dirt and bacteria from reaching your eardrum. It also helps to keep your outer ear canal moist. Ear canals that do not have enough wax tend to become itchy. Cotton swabs should NEVER be stuck inside your ear, because they can damage the sensitive skin of your ear canal, causing it to bleed, and can even hurt your eardrum. Sometimes, using things such as cotton swabs or pencils will push earwax back into the ear canal and up against the eardrum. This is BAD! If this happens, it may be difficult to hear very well. Although there are some over-the-counter remedies for compacted earwax, should this happen to you, you should have your parents call your doctor and ask what the best treatment is. A healthy ear canal will naturally push out old wax, keeping itself clean.

So how do you clean the earwax from outside your ear? All you really need to do is wash your hair to clean your ears. The soap and lather from washing your hair will get into the folds of the auricle, the part of the ear you can see, and help wash away old, flaky earwax. You can also put a cloth over your finger, and wipe the folds of the auricle, but do NOT stick your finger into the ear canal.

Little Lions Experiment:

Materials:

• 2 old paper towel tubes (outer ear canal)
• 2 sheets of facial tissue (eardrum)
• petroleum jelly (earwax)
• dust, dirt or lint (grime)

Steps

1. Tape a sheet of facial tissue to one end of the paper towel tubes. Make sure one end of each tube is completely covered by one layer of tissue.
2. Spread petroleum jelly inside one of the tubes. Leave the other tube without any petroleum jelly. Only spread the jelly in the upper half. Do not let it go too far down the tube. Do not let it touch the facial tissue.
3. Set the tubes beside each other, and prop up the open ends about 30 degrees.
4. Throw the dust towards the tubes.
5. Carefully remove the tissue paper. Compare how dirty the tissue paper got for the tube with the jelly and without the jelly. Did the earwax prevent the grime from hitting the eardrum?

Why Don't Animals Need Glasses?

Roughly, forty percent of people wear contacts or glasses. Some scientists think that the cause is genetic and some think is because of our surroundings.

Scientists have been able to show that people who look out over long distances, like sailors, often do not have problems with short-sightedness or are not myopic (MY-OP-ICK). People such as tailors who have to focus their eyes close to their face often are myopic. It seems that muscles on the side of the eye will correct the eye and help it to see more clearly. If you were to travel to primitive parts of the world, you would see people who have excellent vision without the help of glasses.

Monkeys that have been taken from the wild and held in captivity have been shown to only focus on this close to them. They have become unable to focus far away. Scientists gave chickens glasses and showed that they could cause the chickens to be nearsighted (see things only close to their face, or beaks) for a short time. Imagine a chicken with glasses!

Another theory as to why animals are able to see well is because those that cannot do not live for very long. This is the survival of the fittest theory. That animals that are the strongest will survive the longest and make more animals that are the strongest.

Among domesticated animals, or animals taken from the wild, like cats and dogs, eye problems are likely as the animal gets older. Older domestic animals and humans typically get what are called cataracts (CAT-TER-ACTS). Cataracts are when the front part of the eye becomes cloudy and hard to see through. Have you ever seen an old dog with blue-grey hazy eyes? This is probably because of cataracts.

Little Lion Experiment:

Do you or people in your family wear glasses? Try on some of your family members' glasses and see if you can figure out if they are near- or far-sighted. Do not keep the glasses on too long; they might give you a headache!

Do you see a pattern in the age of the person wearing the glasses and the strength of the glasses? Do older people in the house have stronger glasses than younger people?

A good scientist always looks for trends in the results from their experiments.

Perform a search on the Web for information about the eye and vision problems. Pages like http://www.google.com or http://www.yahoo.com are good search engines. If you just search on eyes, you will get a lot of information.

How Does A Pencil Eraser Work?

The pencil eraser works based on the friction developed between the eraser and the paper. Friction is what causes your hands to heat up when you rub them together. When you rub two objects the roughness of their surfaces contact each other and rub against each other causing friction. A pencil is made of graphite. Graphite is a mineral composed of an element called carbon and is black in color. A pencil mark consists of graphite particles that peel off from the pencil point by the paper. These particles, which have an angular, gritty look under the microscope, are commonly used in hard black (HB) pencils, typically between 2 and 10 micrometres in diameter. This is about 6 times smaller than the thickness of the human hair!

When the pencil is used on a sheet of paper, the graphite particles lie slightly below the surface of the paper, interlocked between its fibers. A single rub using an eraser sufficiently soft to reach between the fibers will pick up most of them. Looking at the eraser you can see undamaged graphite piece sticking to the surface. An effective erasing material scratches the paper surface, producing the familiar small spindles of rubber or eraser material, which wrap up the graphite particles. When you look at these under an optical microscope at 200 times magnification (200x), these look like roly-poly puddings studded with graphite raisins.

Little Lion Experiment:

Erasers come in a variety of colors: white, pink and gray are some of them. Sometimes the color difference is because of a dye or because the eraser is made of a different type of rubber. Go around you house and see how many types of different erasers and pencil leads you have; number two and number three pencils are different types of leads. Remember the bright-colored erasers, like purple and yellow, are usually white erasers in disguise! If someone in your home has a mechanical pencil, you can purchase different types of lead, like HB or soft, they might have different leads you can use. You can also use erasable pen as a lead type. See which one of these works best with different types of pencils and ink. Can you erase the ink with a pink or white eraser? Is there one eraser that works for all lead types? Knowing what you know about how erasers work, why do you think certain erasers do not work with other types of pencil lead and ink?

Thinking about experiments, scientists look at the different things or factors in the experiment called variables. The variables you have in this experiment are erasers and lead types, assuming you always use the same type of paper. A scientist is always concerned about the number of variables in there experiments because it tells them how many experimental runs they need to do. An experiment run would be a single type of eraser against a single type of lead. The total number of experimental runs you would do in your experiment are the number of erasers times the number of leads. By limiting your variables you limit your number of experimental runs, but you don't want to limit your variables too much otherwise your experiment will not be conclusive or lead to a correct answer that may be misleading. For example, if you use all the lead and eraser types in your house, you can say that you have a conclusive study of the erasers and leads in your house. If you just look at the erasers and leads in your room, you could not say that you know about all the erasers and leads in your house, just about the ones in your room. Sometimes scientists limit there variables, like for instances just the erasers in just your bedroom, and then predict from those experiments to say how the erasers in the house would perform. Not all predictions are good, but sometimes it is the best a scientist can do.