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.