Weather: Why do we have weather? Does it serve a purpose?

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Jesse Kelly
5 years ago
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1 Weather: Why do we have weather? Does it serve a purpose? Heat, insulation, the Earth and you: Why people wear different colored clothing in different parts of the world Heat Part I Grandpa, why do people wear heavy, dark clothes in the wintertime and white, thin clothes in the summer time? That s an excellent question. One of the many jobs your body does with the food and water you ingest and the air you breathe is to produce heat. As each cell in your body takes in oxygen and combines it with the food you eat, the cell gives off carbon dioxide, heat and waste material. Just like you have a thermostat in your home to keep the heat a comfortable temperature, your body also has a thermostat keeping it at the temperature at which it works best, 98.6 degrees. Sometimes the weather is hotter than 98.6 degrees, and sometimes the weather is colder than 98.6 degrees. When that happens, the body does things to help your body thermostat control the temperature of the body at 98.6 degrees. For now, since you asked, let s forget about how we help the body by cooling it off and let s just talk about how we keep it warm when it gets colder than 98.6 degrees. When you feel cold, you shiver. Shivering produces extra heat to keep you warm. A second thing happens. The hairs on your body straighten out. That traps more air close to your body and provides insulation to keep you warm. Grandpa, why does trapping air close to your body keep your body warm? With all you ve told me about how the cells provide heat for the body and how an automatic thermostat keeps the temperature at 98.6 degrees, wouldn t you say that someone must have a plan in designing the heating system of the human body? Yes, I would have to agree with you. A man designed our home heating system. It keeps us warm, but it is not nearly as accurately or efficiently as the heating system of your body. It seems reasonable to believe that just as a man designed your home heating system, the creator Jesus Christ designed the very complicated heating system and God s masterpiece, man s body. Grandpa, why does air trapped close to your body keep you warm, and what do you mean when you say that air is an insulator? Heat Part II Grandpa, how does keeping air trapped close to the body keep the body warm, and what does the word insulator mean? If we had a bar of copper one foot long, and we had a thermometer on one end and a small fire on the other end, we would see the temperature of the thermometer go up quickly. Copper is a great conductor of heat. With conductors like copper and aluminum and most other metals, the

2 heat passes to the other end easily and quickly. If we placed a thermometer one foot away from the same small fire with nothing but air in between, we would see little if any change in the temperature. Air is a very poor conductor of heat. A poor conductor of heat is called an insulator, or insulation. If we were to put one end of a bar of copper against our body and ice cubes on the other end of the copper, the 98.6-degree heat would be conducted through the copper bar to the ice. We would be transferring the heat of our body through the great conductor copper to the ice cubes. The ice cubes would melt, and we would be losing heat and our bodies would have to work harder to keep warm. What if instead we were to surround our bodies with air that stays close to our bodies? The poor conductor, the insulator called air, would not transfer heat away from our bodies and we would remain warm. When your hair stands on end, your body is trying to trap air close to your body so that you don t lose heat. When you run or play or exercise you get warm or hot and you even sweat. Moving the muscles of your body creates heat. Honeybees keep their nests, called a hive, warm in the winter by moving their muscles without moving their wings. When we shiver our muscles are moving just like the honeybee. We shiver by moving muscles, and create heat which makes us warmer. Grandpa, when the body shivers, when our hair stands on end, our body is trying to keep us warm. Seems like the planner Jesus Christ thinks of everything. Yes, it s just another way to show His great love for you. Grandpa, I still don t understand why we wear dark coats and sweaters to keep warm. Heat Part III Grandpa, I still don t know why we wear dark coats and sweaters to keep warm? Winter will be coming. It s going to get very cold. Sheep begin to grow a very thick coat of wool. If you press on the wool, it s soft and spongy. What do you suppose makes the wool soft and spongy? It s our old friend, the insulator air. The wool is filled with little pockets of air. It s a lot like the pockets of air a toy might make with soap and water. Your soapy bubbles float away, but the pockets of air trapped in the wool don t move. They are stationary. The sheep s wool holds the air pockets in place. The sheep s body produces heat. The sheep also absorbs heat from the sun s rays, which pass through its wool to the body of the sheep. Pockets of stationary air trapped in the sheep s wool surround his body. The air trapped in pockets in the wool is a poor conductor of heat. Air is an insulator. It may be very cold, but the sheep is very warm. His body produces heat. The surrounding air trapped in his wool does not allow the heat of his body to escape and he keeps warm. One day many years ago in the Garden of Eden, Adam and Eve sinned. God killed a lamb and took its wool covering to hide their shame and to keep them warm. It was God s plan to take the wool of the sheep to keep Adam and Eve warm and to hide their shame. Adam and Eve did not

3 know that it was the air pockets in the wool that kept them warm, but God did, and now so do you. Grandpa, what do people mean when they ask if your home is insulated? Heat Part IV Grandpa, what do people mean when they ask if your home is insulated? We have already learned that copper is a conductor of heat and a very poor insulator. Suppose we build a house and put in a very good heating system. The thermostat keeps the temperature within 4 degrees of where we set it. That s not nearly as good as the thermostat and heating system in your body which keeps the temperature of your body at almost exactly 98.6 degrees. After all, a man designed the heating system of your house. It was God who designed the heating system of your body. After the heating system is built and installed, we build the walls and roof. Should we make the walls and roof of copper? Grandpa, you said copper is a conductor. Yes, and the heat will pass right through the copper walls and roof. If the wind is blowing, the heat will be transferred so fast it will seem like you don t even have a wall. We need to use an insulator to build the walls and the roof. Wood or bricks would make a good wall. After our outside wall is built, we need to build another inside wall, about 6 inches away with air being the insulator between. That will keep us warm inside, right? Yes, it will keep us warmer, but there is another problem about air. Do you remember what we learned about hot air rising above cold air? God made air so that as it gets hotter, it expands and rises above cool air. He did that as a part of His overall design for earth. In His overall plan it was absolutely necessary, but it s a problem in our home. As the air in the six-inch space in our wall heats up, it rises to the attic and the roof. The heat goes through the roof and into space. We have to burn a lot more oil than we want and that s expensive. What can we do to stop the warm air from rising? Supposing we took air pockets trapped in wool from a sheep and filled up the space between the walls. Just as it works for the sheep, just as it works for a coat, it would work in the space between the walls. It would work, but it would be very expensive. Instead, some man had a plan. He made what is called rock wool, which has pockets of air trapped in the rock wool. Then another man planned and invented fiberglass, which is pockets of air trapped in glass, which we call fiberglass. It is used to fill in the space between the walls and the attic. This is a very poor conductor and a great insulator. We fill the walls and attic with fiberglass, which has stationary pockets of air trapped in it. This traps the heat inside the house and greatly reduces the cost of heating the home. We now have a warm home in the winter and a cool home in the summer by using our knowledge of hot and cold air, conductors and insulators. We may not know who designed the walls and roof and heating system in our home, but we would be very foolish to believe it all happened by accident. When we look at the incredible

4 design of our home, space ship earth, shouldn t it be obvious that its truly incredible design demands an incredible designer? Grandpa, how do we keep our home warm when it s cold outside? Heat Part V Grandpa, how do we keep our home warm when it s cold outside? We already talked about insulating our home, but if there is no way to heat our home, won t we freeze in the winter? Many years ago, man discovered fire. One of the advantages of a fire is that it makes heat. The first fires must have been wood fires. I know this will be hard to understand, but a wood fire is really wood being combined with oxygen. One of the problems of a fire is that in cold weather, the part of you facing the fire is hot, and the part of you away from the fire is cold. If you get closer to the fire, you get burned. If you move away you freeze. If the fire is in a room with a chimney, it s a little better. But still, your front is hot and your back is cold. Then someone invented a wood-burning stove. They built the fire inside a metal box. On the top, they placed a chimney, which went outside. That was a lot better. At least you didn t choke on the smoke. The heat easily went through the metal conductor and went into the room. Someone thought of putting a pot of water on top. The water boiled, turned into steam, and warmed the room. That was better, but still not great. Someone tried to burn certain black rocks, which turned out to be coal. Coal was better than wood because it would last a lot longer than wood and you could control the fire better. Notice how many ideas and plans were involved. All of these people involved discovered facts and made plans. Then someone thought, if we have a big metal box over the fire and we connect big pipes to it, the air will heat up and go into different rooms. It was easy to make the hot air go up to the second floor, but it was hard to make it go to the sides. Then a man invented an electric motor, connected it to a fan, and we then could blow the air to the sides of the house. It took a lot of thinking and planning by some very smart people to have an imperfect heating system. Someone decided to have a metal box and put water in it. When a fire was placed underneath, the water boiled and turned to steam. Pipes were connected all over the house to heavy metals boxes that we call radiators. When the fire burned, the water boiled and turned into steam. In doing so, the steam expands greatly and spreads out through the pipes to the metal radiators, which get so hot you can t touch them. If you do you will get burned. The radiators give off heat and the rooms are comfortable to live in. Someone thought, why not use hot water instead of steam? We used a box made of metal. We put water into it. We heated the water with the fire and then used a motor to pump the hot water all over the house into radiators, which heated up the house very nicely. The fire was a great idea. The enclosed metal fireplace was an even better idea. The water pot on top was another great idea. Having the metal box with air in it was a brilliant plan. Using coal instead of wood was another great idea. The plan to use steam was really brilliant. Then using hot water with a pump was a terrific idea. Your heating system in your home is as a result of a series of brilliant ideas and plans by a large group of very creative intelligent designers. With all of this, there is no

5 heating system in the world that even comes close to the heating system in your body. Could you believe that nobody designed the heating system in your home? Of course not! How then is it possible to believe that nobody designed, planned, or created the incredible heating system in your body? Reason demands and insists that your body is the incredible masterpiece of a master designer. In the beginning, God created. Grandpa, why does a hot air balloon go up in the air when the air inside gets hot? Heat Part VI Grandpa, why does a hot air balloon go up when the air inside gets hot? Put air in a balloon and then weigh it. Heat the balloon up. The balloon gets larger. You then weigh the balloon. The balloon weighs the same, hot or cold. There is the same amount of air in the balloon, hot or cold. Hot air takes up more space than cold air, even though the air weighs the same. If I take a one cubic foot block of wood and place it five feet in the air above water and then drop it, the wood falls down through the air, lands and floats on the water. If I take the same block of wood and push it down into water, then release it, the wood will come to the top. A one cubic foot block of wood weighs more than one cubic foot of air, so it falls down. A one cubic foot of wood weighs less than a one cubic foot of water, so the wood rises to the top of the water. Suppose I have two rooms. One room is at zero degrees and another at 100 degrees. Suppose I take a balloon and fill it with one cubic foot of air from the 100 degree room and weigh the balloon. Now I take the balloon and place it in the zero degree room. It is much colder in the freezer. The balloon will slowly shrink in size, but the weight remains the same. The cubic foot area of the now cold air balloon is much less than before. Since the weight is the same in both cases, it proves that cold air per cubic foot will weigh more than hot air per cubic foot. Like the block of wood in the water, the lighter hot air in the balloon rises above the heavier cold air in the room. The hot air balloon rises to the ceiling of the freezer. We return two hours later. The now cold balloon is smaller and sits on the floor. We weigh the balloon. The weight is exactly the same as it was before. During the two hours, the heat in the balloon came out of the balloon and into the freezer. As a result, the balloon shrunk in size, but its weight didn t change. We take the smaller, now cold, balloon and place it into the hot 100 degrees room on the ceiling. The balloon falls to the floor. We come back in two hours and find the balloon on the floor, but it is much larger. We weigh it and it weighs the same. What have we learned? When we take an amount of air and heat it, the air in the balloon expands and takes up more space, but it weighs the same. A cubic inch of cold air weighs more than a cubic inch of hot air. Hot air rises above cold air because it weighs less per cubic inch. Place a thermometer on the floor of a room, then on the ceiling of the same room. You will find that it is much hotter on the ceiling than on the floor. Hot air will always rise above cold air. When we first take out a hot air balloon, it stays on the ground. As we build a fire under the balloon, the air in the balloon gets hotter and the balloon expands. The balloon weighs the same,

6 but per cubic inch it weighs less than the surrounding cool air. The balloon rises into the air. When we turn off the fire, the air in the balloon cools; the balloon gets smaller and comes back down to the earth. We have learned that as air gets hotter it expands and rises above cool or cold air. Grandpa, I saw a candle burning in a jar. I saw a man turn over what looked like an empty jar and the fire went out. It looked like magic. Heat Part VII: How do fires work? Grandpa, I saw a candle burning in a jar. A man appeared to pour what looked like an empty jar over the candle and the fire went out. It looked like magic. No, it was not magic. The jar looked empty, but it was full of a colorless gas called CO 2. Have you ever seen dry ice? It s used to keep things like ice cream cold. If we make CO 2 very cold, it turns to a solid we call dry ice. If we allow it to warm up in a jar we have an odorless, colorless gas called CO 2. If we pour this colorless gas into a jar with air, the denser CO 2 will be pulled below the lighter air by gravity because the CO 2 is heavier than air. Another way of saying this is CO 2 s specific gravity is greater than air. The air is pushed upward and escapes from the jar and the fire goes out. Grandpa, that doesn t tell me why the candle went out! OK, how do you start a fire? We get fuel. The fuel can be wood, paper, oil, gas or whatever. The candle fuel is wax. We strike a match and light the candlewick and we have a fire. There is one thing present that we didn t account for: air. In order for anything to burn we need three things: fuel, a temperature hot enough to burn, and oxygen. Without any one of the three there is no fire. When we pour the CO 2 into the jar, all oxygen is pushed out of the jar and is displaced with CO 2, which will not burn. What we really saw was an invisible gas CO 2 being poured out of a glass into a jar full of oxygen with a burning candle. Since CO 2 is heavier than air, it filled the bottom of the jar, pushing the lighter oxygen up and out of the jar. When the jar was emptied of oxygen and full of CO 2, the flame on the candle went out. Remember, in order for a fire to burn, oxygen must be present. When the CO 2 poured into the jar there was no oxygen to combine with the wax of the candle. As a matter of fact, when firemen want to put out a fire in a gigantic gasoline tank they don t pour in water because the water will go to the bottom and the gasoline will continue to burn. They pour in CO 2. The CO 2 sits on the top of the gasoline and pushes out the oxygen in the tank and the fire goes out. Your parents should keep a box of baking soda on the stove. If a pot of oil catches fire, don t throw water on it because the oil will spill over and burn your house. Do one of two things: 1. Sprinkle baking soda on the burning oil. It will turn to CO 2 and put out the fire, or 2. Put a cover on the pot. The oxygen will burn up quickly and the fire will go out.

7 We have learned several things: 1. Some gases are heavier than others. CO 2 is heavier than air; 2. A fire requires oxygen to burn; 3. A fire is really oxygen and fuel combining. A fire requires three things: 1. Fuel 2. Oxygen 3. A high enough temperature A lighter gas will rise above a heavier gas. A heavier gas will sink to the bottom of a lighter gas. Grandpa, you said sometimes our body gets too hot. When it does, how do we cool it off? Heat Part VIII Grandpa, you said that sometimes our bodies get too hot. When it does, how do we cool it off? The body itself has a means of cooling itself off. It is called sweating. When the body gets too hot, we begin to sweat. When the sweat evaporates, it takes heat from our body and we cool off. That is why in hot weather you should drink a lot of water. If you are sweating a lot, you need to replace the water that you sweat out. Long ago, someone discovered that if you take a fan and wave it, the sweat would evaporate from your body. When the sweat evaporates it removes heat from your body and you feel cooler. With the discovery of electric motors, fan blades were placed on motors. When we got hot, we would sit in front of the fan. The fan would blow air at us. This would cause the sweat to evaporate faster. Heat was removed from our bodies and we felt cooler. It took another smart person to discover an air conditioner. Would anyone ever believe that no one discovered or designed the fan, the motor, the electric fan or the air conditioner? Would anyone believe that it was a series of lucky accidents? How is it possible that people can believe that a masterpiece such as the human body just happened as a series of accidents? Reason demands, an incredible design demands an incredible designer. Any other conclusion is unreasonable. In the beginning God, an incredible designer, designed the heavens, the Earth and all living things.

Thermal Energy. Conduction, Convection, and Radiation. Before You Read. Read to Learn. Conduction. section 2

Thermal Energy. Conduction, Convection, and Radiation. Before You Read. Read to Learn. Conduction. section 2 chapter 5 Thermal Energy section 2 Conduction, Convection, and What You ll Learn the three ways heat is transferred the difference between insulators and conductors how insulators control the transfer