How Do Plants And Water Break Rocks?

You have probably seen people use big hammers to break rocks (in movies) or bulldozers to knock down large buildings. Did you know that plants too can break rocks? Have you seen tiny plants come out of cracks in the road or a concrete sidewalk? It is amazing to see a tiny plant break apart a big rock as it grows in a crack in the rock.

Plants exert a large amount of force on everything around them. All this hidden strength in plants and seeds come from the process of imbibition. Imbibition simply means taking up or absorbing water. This process can be understood by knowing what plants are made of.

Plants are made up of millions of little cells. Cells are the building blocks of living organisms. In plants, the cells are close together but are still set apart by a large number of pores, empty spaces between cells in plants.

Each cell in a plant has a flexible outer covering called cell wall. When the plants or seeds are near water, they absorb the water into their pores and also into the cells. Since the cell wall is flexible, it allows the cell to expand in size and yet not break.

The expansion of all cells is what causes a seed to enlarge so much or wood to swell. Did you know that long, long ago (several thousand years ago) the people who built pyramids in Egypt and temples in India used the power of the swelling in wood to break large rocks?

They used to place wooden wedges in cracks of large rocks, pour some water, and wait. In a few days the wood would swell up and slowly crack the rock open. Then the broken rocks were used to build pyramids and stones. The ancients even used the swelling to wood to lift the rocks, but that story is difficult to explain here!

Other fun experiments on plants are at: http://mgonline.com/experimentsforkids.html. It is going to be spring time so growing plants is the fun thing to do! For information on pyramids and temples visit: http://www.historyforkids.org/learn/egypt/architecture/egyptarchit.htm and http://www.templenet.com/tamilnadu.html.

Little Lion Experiment:

The great strength of wood-based materials when they expand due to water absorption can be easily shown at home. Seeds and beans (whole dry beans) are similar to woody matter and swell if soaked in water over a few hours. The interesting thing with soaking beans or seeds in water is that you will end up getting sprouted beans after a couple of days.

This experiment can be set up in few minutes, but will show results only after few hours, so some patience will be needed. You will need these materials:

• dry beans (green mung beans, or red kidney beans or garbanzo beans - you have to use dry beans)
• a small plastic container with a lid (yogurt containers with clear lids work best)
• water
• a large plastic bowl or plate

Steps:

1. Fill the container with dry beans leaving small amount of room at the top.
2. Set this container into the large bowl or plate.
3. Add water slowly to the beans until you see water reach the top.
4. Place the lid on the small container and close it firmly. If you use plastic wrap, you can clasp it tightly to cover the top and then put a rubber band around the container wall.
5. Write down the time, and check the container at intervals of 1 hour.

Why Is Natural Gas A Cleaner Energy Source?

Coal, oil, and natural gas are all important fossil fuels for heating our homes, generating electricity, and fueling vehicles. These energy sources are called fossil fuels because they are formed from the fossilized remains of plants and animals that lived thousands of years ago.

However, even though all three fossil fuels are formed from decaying organisms (living things), both coal and oil produce a variety of harmful byproducts when burned, while natural gas only produces carbon dioxide and water vapor when burned. This is due to differences in their final chemical compositions, which are due to the different processes (trapping, compaction, and heating) naturally taking place underground.

In general, natural gas has the simplest chemistry and is only made of one carbon atom and four hydrogen atoms (atoms are the fundamental building blocks of all matter), while coal and oil are much more complex.

The simple chemistry of natural gas allows it to have almost 100% energy conversion when it is being burned. This means that the majority of the fuel is being utilized for power needs and only a small amount of the fuel is not being used for power needs.

On the other hand, the harmful byproducts that coal and oil produce are a result of their incomplete energy conversion. Therefore, natural gas is considered to be the cleanest burning fossil fuel.

For more information and fun games on natural gas safety, check out Sierra Pacific's Natural Gas Safety World at http://www.sierrapacific.com/kids_safety/gas/index.html.

And if you ever visit Centre County, you will find that the CATA buses around town are actually running on natural gas! Check out their website for more information on these environmentally friendly buses: http://www.catabus.com/accngprog.htm.

Little Lion Experiment:

Natural gas collects underground by seeping into and passing through reservoir rock (a layer of spongy rock). To keep the natural gas from moving or leaking to the earth's surface, a different layer of rock called cap rock (a layer of solid rock) exists above the reservoir rock. The combination of these different rock layers allows the natural gas to accumulate until it is ready to be used for energy needs.

This experiment will help you to understand the different ways that natural gas can be trapped underground. You will need these materials:

• sand
• clay
• two 8 oz. wide-mouth glass jars
• 16 oz. of water
• magnifying glass

Steps:

1. Feel the sand and clay with your hands. Do they feel different?
2. Examine the sand and clay with the magnifying glass. Do they look different?
3. Put the sand into one glass jar and the clay into the other glass jar. Fill each jar about 2/3 full.
4. Add the water to each jar to fill the remaining space.
5. Observe the water's behavior - Is it passing through the sand or clay to the bottom of the jar? Or is it sitting on top of the sand or clay?

The material that allows the water to pass through is acting like reservoir rock underground, which allows water to seep in. This is similar to how natural gas accumulates underground. The material that does not allow the water to pass through is acting like cap rock because it is stopping the movement of the fluid. This explains how natural gas can be trapped underground.

Why Do We Laugh

We've all had the experience of laughing at something funny, but what exactly are humor and laughter? From a biological standpoint, laughter is a certain set of vocal sounds and physical movements occurring together (the biological study of laughter is called gelotology).

Laughter has also been shown to be beneficial to our general health. So, laughing is not only fun, but it's also good for you! That's lucky for us, since the average person laughs 17 times per day. That amounts to about one episode of laughter per waking hour!

Humor is a very complex topic. Realizing that something is funny involves many of the same areas of the brain as problem solving does. Humor also involves the frontal lobe (the part of the brain that allows us to experience social emotions).

Brain activity then spreads to the occipital lobe, which processes signals. Finally, the motor (i.e. movement) portions of our brain produce signals to bring about the physical movements associated with laughter.

Researchers have found that humor falls under 3 main categories:

1. Surprise: something strikes us as funny when it is contrary to what we expected to happen. Whenever someone starts a sentence, or an action, our brains predict what will follow. So, when a comedian sets up a joke, we think we know where the story is headed, but the punch-line surprises us, and so our brain interprets that as being funny.
2. Feeling superior: as much as we don't like to admit it, sometimes we laugh at others. mistakes or misfortune. This is what is commonly known as "making fun of someone." This humor is the result of our enjoying the emotion of feeling superior to the person we are laughing at. This type of humor is not polite and is not particularly kind either, so we often train ourselves not to indulge in it.
3. Relief: humans laugh at stressful situations as a way to cope with stress and anger. For example, if you're walking to school without an umbrella, and it starts to rain, you may feel frustrated or angry, but you will most likely chuckle at the situation. "Nervous laughter" also falls under this category since it serves to reduce tension in social settings.

Little Lion Experiment:

Laughter is a very important part of our social interactions. Studies have shown that people are much more likely to laugh at something funny when they are with other people than when they are alone. This explains why watching a comedy in your living room just doesn't live up to the experience of watching the same movie in a crowded movie theater.

For a week, keep a tally of how many times per day you laugh. Record whether you were alone or whether you were with other people each time you laughed.

Estimate how many waking hours (i.e. hours when you weren't asleep) you spent alone. Divide the number of times you laughed alone by the number of hours you were alone. This will give your rate of solitary laughter (how many times per hour you laughed alone).

Then, divide the number of times you laughed with other people by the number of hours you spent with other people. This will give your rate of social laughter (how many times per hour you laughed with other people).

Compare your rate of solitary laughter with your rate of social laughter.

Why Are Arteries and Veins Different Colors?

If you've ever stared at the blood vessels (veins and arteries) in your wrist, then you've probably noticed that your arteries look purple and your veins look blue. However, this is an illusion of nature; arteries and veins are actually both whitish in color! This illusion is due to the way that different wavelengths of light pass through our skin.

White light is composed of the different colors of visible light (red through violet). Each of the colors has its own set of wavelengths, with red having the longest wavelengths and violet having the shortest wavelengths.

Long wavelengths penetrate our skin more easily than shorter wavelengths do. So, red light can penetrate deeply enough into our skin that it reaches our blood vessels, where it is absorbed.

In contrast, blue and violet wavelengths are so short that they can not penetrate our skin very well. This means that they are reflected back at our eyes before they have a chance to be absorbed.

Therefore, when we look at blood vessels under our skin, we see the blue and violet light that is being reflected back at us, so our veins and arteries appear to be blue and purple even though our blood is not actually blue!

But why aren't veins and arteries the exact same color as each other? The answer revolves around the fact that arteries carry oxygenated blood (blood that contains a lot of oxygen) away from the heart, while veins return the deoxygenated blood (blood with less oxygen) from the tissues to the heart. [An easy way to remember this difference is to think arteries = away.]

When we inhale air, oxygen passes from our lungs into our deoxygenated blood. This addition of oxygen means that the blood is now oxygenated. The heart then pumps the oxygenated blood through the arteries to the rest of the body, where some of the oxygen is then used by our tissues (which make up our bodily organs). The leftover (deoxygenated) blood is then returned to the heart by our veins.

Oxygen changes the color of blood in such a way that oxygenated blood is a very bright red color, while deoxygenated blood is a darker red (not blue as some people believe). Now it should make sense why arteries are a bit redder than veins!

Little Lion Experiment:

Besides color, another difference between arteries in veins is that arteries pulsate (expand and contract) much more than veins do as blood flows through them. The slight changes in the shape and size of our veins is so slight that you can't even feel it.

In contrast, you can feel the pulsing of your arteries just by pressing your finger gently over an artery. This is called "finding your pulse." The two easiest places to find your pulse are on the groove of the underside of your wrist and on your neck right below you ear.

A person's pulse reflects how often blood is pumped between their heart and their blood vessels. In other words, it shows how hard their heart is working to get enough oxygen to their body.

To see how your pulse changes with the changing demands that you place on your body, place a watch or clock with a second hand in front of you. Sit still for 5 minutes, then press your index finger gently over your wrist or one side of your neck. Record how many times your feel a pulse in 12 seconds. Then multiply this number by 5 to get the number of pulses in one minute (5 x 12 seconds = 60 seconds = 1 minute). This number is called your resting pulse.

Next, if you are physically fit to do so, jog in place for a minute, do 30 jumping jacks, or do some other safe form of exercise for about 1 minute. Immediately after that, sit down and record how many times your feel a pulse in 12 seconds. Then multiply this number by 5 to get the number of pulses in one minute.

Compare your resting pulse to your pulse just after your exercised to see how much harder your heart has to work when you move around. This difference shows that physical activity requires extra oxygen since your tissues need oxygen in order to make energy.

How Do Microwaves Work?

When you drop a stone into a pool of water, you see waves. Ripples in the water bounce up and down. The waves form circles around the spot where the stone hit the water. The ripples start small but then they move away from the center, in bigger and bigger circles. The frequency of the waves represents how quickly they are bouncing up and down.

Microwaves are a type of radio wave. Appliances such as your radio, cordless telephones, cell phones, and television all function by radio waves. Radio waves are like water waves, but you can't see them.

In addition, radio waves work on a much smaller scale. Everything in the universe is made up of atoms (the fundamental building blocks of all matter). The most mobile parts of an atom are called electrons. When radio waves hit an object, they make the electrons in that object bounce around.

High frequency radio waves have more energy than low frequency waves do.

Microwaves are very high-frequency radio waves. They are used in cell phones, wireless Internet, and in microwave ovens.

The waves in cell phones and wireless Internet do not get very much electricity, so these waves are very weak. In contrast, lots of electricity runs through a microwave oven, so microwaves are strong.

Just as water waves make things move, microwaves make atoms move. The atoms bump into each other, and the resulting friction makes the food get hot.

In a microwave oven, a radio makes microwaves and sends them in one direction. They are aimed at a spinning fan that sits above or beside the food inside. Sometimes you can see the fan, but most of the time it is hidden behind plastic.

When the microwaves hit the spinning fan, the waves bounce off and hit the food. The microwaves then get absorbed by the fats, sugars, and especially water in the food. Once absorbed, the microwaves cause the electrons in the food to vibrate. This generates heat, which can then evenly heat up your food.

Microwaves can bounce around inside the oven. The metal walls of the oven keep the microwaves from escaping into the surroundings. Even though you can see the food while it's cooking, the microwaves won't bounce out of the glass door because the metal screen stops them. Still, it is not good to be too close to the oven when it is cooking.

For more fun information about the science of microwave ovens, you should explore these interactive websites!

• Dr. Electric's Microwave Oven Laboratory at http://www.discovery.panasonic.co.jp/en/lab/lab02mw/
• Professor Lee's Microwave Oven Laboratory at http://www.colorado.edu/physics/2000/microwaves/

  Little Lion Experiment

  The microwaves used in microwave ovens are specially designed to heat up water molecules since food is mostly water.

  Get two crackers that are the same size and type. Moisten one cracker with room-temperature water. Put both crackers onto a napkin and microwave them for 7 seconds. Safety note: wait 20 more seconds before opening the microwave door so that the heat will have a chance to spread out evenly over each cracker! Feel both crackers with your finger. Which one is warmer? Why?

Why Do Plants Wilt?

If you've ever forgotten to water your house plants, then you've probably noticed that they begin to wilt. Most of us naturally know that wilting plants need water, but exactly why is it that dehydrated (thirsty) plants wilt?

The answer is that plant cells contain many organelles (compartments), one of which is a very large vacuole (storage compartment) for water. When filled with water, this vacuole pushes out against the cell wall (a rigid layer which wraps around the plant cell to support it). This resulting outward pressure is called turgor pressure.

When it rains, or when you water a house plant, some of the water absorbed by the plant's roots is used to carry out cellular processes, some is used to transport nutrients (the plant's equivalent of an animal's blood circulation), and the leftover water is stored in vacuoles in the cells.

So, when a plant is well-hydrated, its vacuoles swell with water. Thus, the turgor pressure inside each cell is high. This supports the wall of each cell and makes the plant cells stiff. This stiffness is what allows plant stems to stand up straight (plants rely on turgor pressure since they do not have bones to support their "limbs" against gravity).

In contrast, when a plant gets dehydrated, it must use its vacuoles as a source of water since water is so important for every cell to function. So, some of the stored water must exit the vacuoles so that it can be used. This is similar to a town's water tower: when the town is well-supplied with water, the tower stays full, but when there is a water shortage, the stored water in the tower is drained out and used to support the townspeople.

As you can imagine, when the vacuoles are drained, they shrink and thus do not push outward on the cell wall anymore. This lack of turgor pressure causes the plant to wilt.

Little Lion Experiment:

Cut a grape in half and peel the skin off of it. If you don't have grapes, then cut a thin (1/4") slice of an apple. Notice how the fruit is rather stiff.

Next, to cause dehydration, cover the piece of fruit with salt for 10 minutes. The salt will draw some of the water out of the fruit. For the best results, scrape the wet salt off of the fruit and replace it with a new sprinkling of salt every 2 minutes.

Now, you have dehydrated the fruit cells so that their water vacuoles are depleted (i.e. they contain less water than they used to). This is similar to what happens when you forget to water your house plants. Feel the fruit to see how dehydration affected the stiffness of the plant. Can you explain your results with regard to turgor pressure?

Food for thought: if you left the grape in salt for a very long time, you'd end up with something similar to a raisin. A raisin, after all, is just a dehydrated grape! It still has the same amount of skin around it, but that skin is wrinkled because the volume of the raisin is much less than the volume of the original grape. This difference in volume shows how much water was lost. So, since grapes are so much larger than raisins, you can see that the main component of grape cells (and in fact all living cells) is water!

Why Do Onions Make Us Cry?

Many people enjoy the taste of onions in their meals. Indeed, the average American eats about 18.3 pounds of onions each year. Onions are healthy components of the human diet because they contain vitamins B and C, protein, calcium, iron, and quercetin (an antioxidant, which helps to neutralize harmful substances in our bodies that cause tissue damage and aging). In addition to being full of nutrients, onions are low in fat and sodium.

However, if you have ever cut into an onion, it is likely that your eyes filled with tears. Why does this happen? How can we enjoy the taste and benefits of onions without the tears? Read on to find out.

When you cut into an onion, an enzyme (i.e. a molecule that speeds up chemical reactions) called lachrymatory-factor synthase is released into the air from the ruptured onion cells. This enzyme converts some of the proteins in the onion into sulfenic acids, eye irritants which are responsible for the flushing action of our tears. Sulfenic acids are also responsible for the strong odor of raw onions.

So, how can we enjoy the benefits and the great taste of onions without the tears? Here are several methods that can reduce the amount of sulfenic acids that reaches the eyes:

• After peeling, put the onion in the refrigerator or freezer for a few minutes to slow the speed of the chemical reaction.
• Run the onion under cold water while slicing, or cut it underwater.
• Cook the onion before slicing.
• Do not rub your eyes, because they will be coated in irritating compounds from the juice of the onion.
• Cut the onion in a plastic bag with the bottom cut out.
• Turn the vent fan on high and place your cutting board next to the stove top.
• Try pouring a small amount of white distilled vinegar on your cutting board before slicing.

Over time, it is even possible to develop a tolerance for the chemical, reducing the amount of reaction.

Go on, put your new eye defense skills to the test with the help of a parent or other handy adult with the Little Lion experiment of the month!

Little Lion Experiment:

This onion soup recipe from the National Onion Association is full of flavor, and makes a tasty treat. To make it, you will need:

• 4 large yellow onions
• 6 tablespoons butter or margarine
• 1 tablespoon sugar
• 2 quarts reduced sodium chicken broth
• Salt and pepper to taste
• baguette French bread, sliced and toasted
• Grated Romano cheese
• An adult to help you

To begin, slice the onions, using any of the above methods to reduce eye irritation. Be careful with the knife, and always point the sharp part of the blade away from you when cutting. Melt the butter or margarine in a large saucepan that holds at least 4 quarts. Next, add the onions and cook over medium heat, stirring often, for 12 minutes or until tender and golden. Add sugar and stir for one minute. Next add broth, cover, and bring to a boil. Reduce heat, and simmer for 12 minutes. Season the soup with salt and pepper to taste.

Finally, ladle soup into bowls and top with toast and cheese. Enjoy!