Science Lab - Sound Waves

8th Grade - Physical Science

A. Purpose: The purpose of this experiment is to allow the experimenter to gain a stabilized understanding of the medium through which sound waves travel via two different experiments. The experimenter will establish knowledge about sound waves and physically see the results of those sound waves in motion. Sound waves are an important section of science that is useful for every student to understand. Features of these sound waves will be demonstrated clearly throughout the simple experiment.

While sound waves are often explained to students like waves of the ocean, rolling from one point to another, the reality is that there are, in fact, two kinds of waves. Transverse waves are waves like those found in the ocean, while longitudinal waves are the kind of waves that sound travels by. Many scientist contributed research to this phenomenon, but by far, James Clerk Maxwell's works during the mid-nineteenth century have best demonstrated the conclusion that sound is a longitudinal wave. (Wikipedia) The 1800's were a great time where science thrived in technological advances. (sciencemuseum.org) The question in the mid-1800's, though, was what do sound waves travel through? Or, what is the medium through which sound waves travel? A medium is a substance or object that something such as sound waves or light, can oscillate. For example, when a man is walking down the sidewalk, air is the medium through which he is oscillating, but when the man goes swimming, water is the medium through which he is now traveling.

This experiment hopes to show the results and affects of sound waves in motion. Above all demonstrations will be performed to determine the medium through which those sound waves travel. The student will hopefully gain a better understanding of both sound waves and their consequences. Usefulness of this knowledge is beyond helpful, but almost necessary.

The intelligence of how sound waves oscillate is essential to the young mind's knowledge as a student. Sound waves are an important part of science as a whole and must not be skipped over in the learning process. Understanding of this phenomenon is useful to understanding of many more topics of further study. This topic is of interest to science in many fields.

Hypothesis: If plastic wrap is placed tightly around a bottomless 2-liter plastic bottle, and that bottle is placed upside-down next to a lit candle, and the plastic wrap is gently flicked with one finger, then the flame will go out due to the sound waves exiting the bottle. Furthermore, if plastic wrap is placed tightly over the top of a large glass bowl, and a small amount of rice is poured on top of the plastic wrap, and a pan is held up over the bowl, while a spoon thumps the back of the pan, then the rice will begin to “jump” around due to the sound wave oscillating from the the pan.

B. Equipment:

1. Plastic wrap

2. Scissors

3. Tape

4. Candle

5. Match

6. Plastic 2-liter bottle

7. Large pot

8. Wooden spoon

9. Large bowl

10. Rice

C. Procedure:

Procedure for Experiment #1:

1. Cut away the base of the plastic bottle so that there is a big hole at the bottom.

2. Use the plastic wrap to cover the hole that was created when the bottle's base was cut away.

3. Flick the bottom of the bottle to hear the dull thump.

4. Hold the bottle so that the opening from which you drink is pointed toward the experimenter's ear. 5. Flick the plastic wrap again and heat the sound as it comes through the bottle.

6. Light the candle.

7. Hold the bottle so that the opening from which liquid is poured is right at the flame. Try to hold the opening as close to the flame as close as possible without melting it or catching it on fire. When the bottle opening is positioned properly, flick the plastic wrap at the other end so you hear the dull thump.

8. Note the result.

Procedure for Experiment #2:

1. Stretch the plastic wrap over the top (open end) of the large bowl.

2. As was did in previously in the first experiment, make sure the plastic wrap is stretched tightly across the bowl.

3. Spread some rice over the plastic wrap that is stretched across the top of the bowl.

4. Bring the large pot near the bowl, holding it so the top of the pot (the open end) points toward the top of the bowl.

5. Use the large spoon to start banging against the bottom of the pot.

6. Watch the rice.

7. Clean up the mess.

D. Observations

Observations for Experiment #1:

1. Bottom of bottle is cut away easily with large right-handed scissors.

2. Plastic wrap is stretched across open hole at bottom of bottle with ease. Outer edges are somewhat wrinkled.

3. Plastic wrap makes low-pitched, dull thump when gently flicked.

4. Bottle is held up to experimenter's ear with the experimenter's right fingertips. Plastic wrap is flicked. Thump is much louder than before.

5. Candle is lit with match. Experimenter's index finger suffers a moderate burn.

6. Bottle is held up to the fire with the small opening upside-down. Bottle end is approximately ½ in. away from flame.

7. Flame is blown out. Thin stream of smoke rolls from candle tip.

Observations for Experiment #2:

1. Plastic wrap is stretched across bowl with ease. Edges are slightly wrinkled.

2. Plastic wrap is double checked by experimenter. Wrap is extremely tight.

3. Approximately 47 grains of cheap, Kroger brand white rice are spread across wrap.

4. Large black pot is held up 3 inches away from the bowl by experimenter.

5. Large metal spoon is banged consistently against the back of the pot by experimenter. Family of experimenter becomes more or less annoyed.

6. Rice begins to “jump” around on top of wrap.

7. Supplies are put back where experimenter originally found them.

E. Conclusions:

Hypothesis was confirmed. The candle flame was most definitely blown out, an the rice jumped like mexican jumping beans. The reason for both of these results are simple. When the plastic wrap on the bottle was flicked next to the candle, sound waves were created from the vibrations. As these sound waves traveled through the bottle, AIR was pushed out of the bottle, blowing out the candle. Air. Does this mean air is the medium through which sound travels? Yes! The second experiment confirmed this. When the pot was struck with the spoon, sound waves were created by the vibrations, air was pushed away from the pot, blowing the rice, giving the impression that the rice was jumping.

This experiment could not be improved much. The results were easy to recognize and conclusive. The only thing that might possibly be changed is the second experiment. The pan was slightly awkward to hold, and the experimenter had to strike the back quite hard in order for a result to be seen. This mild dilemma can be fixed by using something with a thinner back.

Ideas for future research are difficult to distinguish due to the simplicity of the experiment at hand. Sound waves, it seams, can only be discovered to a certain degree. Although, the pursuit of knowledge should never be underestimated or defined. Future research will always be necessary in order for science to expand it's interests and fields of study.

F. Bibliography:

Rosenoff, Steven. Classroom Lecture. April 12, 2012.

The contributors of Science Museum, “Science and Medicine”.

Domain: http://www.sciencemuseum.org.uk

Document:/broughttolife/themes/science.aspx

Wikipedia contributors, “TransverseWaves,” Wikipedia, The Free Encyclopedia

Domain: http://en.wikipedia.org/

Document: wiki/TransverseWave

Wile, Dr. Jay L. Exploring Creation with Physical Science, 2^nd Edition. Apologia Educational

Ministries, Inc. 2007

Science Lab - Force and Circular Motion

8th Grade - Physical Science

A. Purpose: The purpose of this experiment is to demonstrate the properties of circular motion and the force that upholds it. The force required for circular motion to occur properly is a special force called centripetal force. An example of centripetal force will be performed in the following experiment, which is very helpful for any experimenter in order to produce a true understanding of the unique and complex force regarding circular motion. Centripetal force is a hard concept to grasp, but evaluating the reasons and results will certainly be of great assistance.

Centripetal force is basically defined as the force necessary to make an object move in a circle. It is always directed perpendicular to the velocity of the object. This means that the force always points toward the center of the circle. One example of centripetal force is a loop on a roller-coaster. In this case, the track applies a centripetal force on the cars. The cars initial velocity is traveling forward, but the track is applying the force, the centripetal force, on the cars, which causes the cars to begin traveling in a circle. Yet another example is in the solar system. Earth for example is traveling through space at thousands of mile per hour. The gravitational force of the sun however causes the earth to bend its initial velocity. The sun's gravitational force acts as the centripetal force in this case. Sir Isaac Newton explained centripetal force in this statement, “A centripetal force is that by which bodies are drawn or impelled, or in any way tend, towards a point as to a centre.” (Wikipedia)

Centripetal force was first put into mathematical definition by Dutch scientist Christiaan Huygens. Although his formula for centripetal force is extremely complex, three basic laws of centripetal force have been accumulated over time. They are:

1. Circular motion requires centripetal force.

2. The larger the centripetal force, the faster an object travels in a circle of a given size.

3. At a given speed, the larger the centripetal force, the smaller the circle.

These are the three laws that have helped many grasp the concept of centripetal fore itself.

Centripetal force is often mistaken for centrifugal force. Centrifugal force at times seems rational, but is actually a fake. Centrifuge is the Latin word for “center fleeting” (regentsprep.org). While many believe that centrifugal force is the reason mud spins off tires, or passengers lean to one side in a car turning a curve, those are really just results of Newton's first law of motion, which states,”An object in motion (or at rest) tends to stay in motion (or at rest) until acted on by an outside force.” So then, the reason car passengers are thrust to one side during a curve is that their bodies are staying in motion until the physical car makes them turn with it.

This experiment hopes to show the reality of centripetal force. Circular motion will be explained in a manner as to easily be understood by the ordinary person. Also, centrifugal force shall leave one's mind as a simple myth, and not a fact. This experiment will show as well the benefits of centripetal force using easy, everyday materials.

This experiment is of interest to science because without centripetal force, there is no way earth could survive. Centripetal force is something unknowingly used everyday. If no one discovers the superior value of understanding this unique force, then man is left being content with seeming unintelligent.

Experiments such as this one are important so that the reality of centripetal force may be shown in easy ways.

Hypothesis: If every step is proceeded as necessary, and the washers are spun at the exact speed needed, then the goal of centripetal force being demonstrated will be successful.

B. Supplies:

1. A mechanical pen

2. A black marker

3. Thin string or thread

4. Five metal washers

5. Stopwatch

6. Scissors

C. Procedure:

1. Unscrew the bottom part of the casing from the pen and remove the insides from the pen.

2. Set everything aside except for the bottom part of the casing.

3. Thread about a foot of string through the casing. If you is having trouble getting the string all the way through, stick the string in the pointed side of the casing and suck on the other side with mouth. The suction will pull the string through. Tie one washer on the end that is on the pointed side of the casing and tie two washers on the other end.

4. Lay your device on the table and pull the string so that about 6 inches of string comes out of the pointed side of the casing. Next, use your marker to make a strong black mark all around the string, right where it comes out the other side of the casing. The mark needs to be easy to see.

5. Hold the device by grasping the pen. Make sure that the pointed end of the pen points up. Begin twirling the single washer on the end so that it moves in a circle.

6. Get used to how this thing operates. Notice that as you twirl the washer faster, the string pulls out the end, causing the circle that the washer sweeps out to become larger. If you slow the twirling down, the string goes the other way, making the circle smaller.

7. Adjust the rate you are twirling until the black mark you made is visible right at the bottom of the pen casing. This tells you that there are 6 inches of string extended from the point end of the casing. In other words, the radius of the circle swept out by the single washer is 6 inches.

8. Watch the washer as it moves in a circle. You are going to begin counting the number of full circles the washer makes. This can be a little tricky, so get used to the motion of the washer, keeping the black mark just at the bottom of the casing.

9. When you're ready, start the stopwatch and time how long it takes for the washer to make twenty full circles. Do this five times and average the result.

10. Next, tie two more washers to the end of the string that already had two washers on it. That way, there are now four washers on one end and one washer on the other. 11. Repeat steps (5-7) determining how long it takes the washer to make twenty full circles in this new configuration. 12. This step might be hard, but try to do it anyway. Try to twirl the washer so that the time it takes the washer to make twenty full circles equals equal to the time in step 7, when you had only two washers on the other end. In other words, if you are trying to twirl the washer with the same speed as in step 7.

This does not need to be done perfectly, just try to get reasonably close. 13. Notice where the black mark is when the washer twirls with the same speed as it had in step 7. 14. Finally, while the washer is still twirling around, cut the four washers off the string with the scissors. Make sure no one else is near when this is done. Also, make sure there are no breakables in the room. Note what happens. 15. Clean up the mess.

D. Observations:

1. Casing is removed cleanly and easily, inside of pen can be described as any other inside of a pen.

2. Everything is set aside with ease

3. String is threaded through the casing, although suction with the mouth was necessary. Two washers are tied on one side with a basic square knot, and one washer is tied on the other end using the same method.

4. Six inches of string are pulled from the pointed side of the casing. Sharpy brand black marker is used to mark. Mark is thin but bold.

5. Pen casing is held as directed. Top washer begins to spin fairly easily counter-clockwise.

6. Adjusting of spinning speed is attempted. Spinning begins to become more natural.

7. Black mark is visible at bottom of casing.

8. Washer is watched carefully. Preparing to count soon.

9. Iron Man brand stopwatch is started. Washer makes twenty full rounds and the watch is stopped. This is repeated four more times. Average time turns out to be just at 10 seconds.

10. Two more washers are tied onto the side with two washers already attached. Same square knot is used to tie the second two on. Four washers are now on one side of the string, and one remains on the other side.

11. Steps (5-7) are repeated, and average time taken for washers to make twenty full rounds comes to about 5. 27 seconds.

12. Step is extremely difficult, but closest attempt trying this came to a time of 9.86.

13. Black mark is well below pen casing.

14. Washers are cut with orange and gray scissors. Lone washer flies of in a straight line, nearly colliding with a television.

15. Mess is cleaned up in approximately 4 ½ minutes.

E. Conclusions:

This experiment was extremely successful in proving the existence of centripetal force. The above hypothesis was confirmed in demonstrating the effects of circular motion, and centripetal force. The washers made great example objects to show these effects. When two more washers were added to the bottom end of the casing, it demonstrated the second and third law of centripetal force very clearly and easily.

Honestly, there is no way that this experiment could possibly be improved. Besides the fact that the particular experimenter of this procedure could have made sure to stand a little farther back from the television, it was a perfect success. The usefulness of this experiment can be varied for many reasons of education and research. The washers could be substituted with any other reasonably small, heavy objects, or for larger scale operations, the general build could just be enlarged for official scientific research.

Ideas for future research are hard to generate when it comes to centripetal force, because scientists believe that research in this particular field has gone as far as possible. Of course, science has never gone as far as is can go. For man can never know when all facts have been discovered. Perhaps further research can be established throughout the process of constant discoveries made every day in the field of science.

F. Bibliography:

Joy Wagon,“Centrifugal Force, The False Force” Regents Prep

Domain: http://regentsprep.org

Document: /regents/physics/phys06/bcentrif/centrif.htm

Wikipedia contributors, “Centripetal Force,” Wikipedia, The Free Encyclopedia

Domain: http://en.wikipedia.org/

Document: /wiki/Centripetal_force

Wile, Dr. Jay L. Exploring Creation with Physical Science, 2^nd Edition. Apologia Educational Ministries, Inc. 2007

Science Lab - Atmospheric Pressure

8th Grade - Physical Science

A. Purpose: In this experiment, the experimenter will demonstrate how the atmosphere exerts pressure on everything it encounters. Observations will be made of both the positive and negative consequences of atmospheric pressure. The experimenter will then discover why and how these consequences occurred. Finally, there will be nothing to do but marvel at how intelligently The Creator has built this world.

Air exerts pressure over the entire earth. That air is called atmosphere. The earth's atmosphere reaches up higher than 460km above sea level. All of this air pushes down on everything at the surface. Atmospheric pressure varies widely over the earth. These changes are extremely important when studying weather (Wikipedia). It is because of these changes that climbers have a difficult time breathing at high altitudes. (universetoday.com)

As imagined by many people, all this air becomes quite heavy. In fact, every square inch of earth is being pressed down by an average weight of 14.7 pounds. As a result, there is an average weight of 176 pounds being pressed down on every fully-grown human being. The reason humans do not feel as if they are holding up 176 pounds is because God already has a solution for this heavy burden. Although the air around a person is pushing in on them, the air inside of them is pushing out. Therefore, the air inside and out cancel out each other and the person does not feel any weight pushing down on them.

This experiment hopes to show the reality of atmospheric pressure. The experimenter hopes to demonstrate this by observing and aluminum can in two very different situations. The first time the experimenter will study the can under normal conditions. The second time the can will be observed when no air is inside of it.

This experiment is of interest to science because the earth's atmosphere is a major ingredient for survival. Because the atmosphere is so important, it is necessary to try and understand everything about it possible. Atmospheric pressure is beyond important to science, it is indispensable. The sheer knowledge of it is useful to practically everything science explores.

Hypothesis: If the can is robbed of all the air it contains inside of itself and dumped upside down in the water so that no new air could not possibly enter back inside, then the atmospheric pressure on the outside will cause the can to implode.

B. Equipment:

1.Stove

2.Frying pan

3.Two empty, 12-ounce aluminum cans (like soda pop cans)

4.Two bowls

5.Water

6.Ice cubes

7.Tongs

8.Eye protection such as goggles or safety glasses

C. Procedure

1. Put a small amount of water in each aluminum can. You should use only enough to cover the bottom of the can with a small amount of water. The more water you use, the less dramatic the effect.

2. Place the two aluminum cans in the frying pan so that they stand up.

3. Put the frying pan on the stove and turn the heat up to “high”. This will heat up the water in the cans.

4. While you are waiting for the water in the cans to heat up, fill each bowl half full of water.

5. Place a few ice cubes in each bowl so that the water becomes ice cold.

6. Wait for steam to start rising out of the opening of each can. That will tell you when the water inside is boiling vigorously.

7. Once a steady stream of steam is coming out of each can, use the tongs to grab one can and place it upright in one of the bowls of water.

8. Note what happens.

9. Use the tongs to grab the other can and place it upside down in the other bowl of water.

10. Note what happens.

11.Clean up your mess.

D. Observations:

1. The two cans are filled with an extremely small amount of water from the faucet. Water is clear and the cans are completely empty.

2. Cans are placed on frying pan and stood up with little effort from the experimenter.

3. Frying pan is placed upon the stove without anything breaking. Water begins to heat up as expected.

4. Water in each can continues to heat up. Water from tap flows into both bowls. Water is clear and appears normal.

5. Ice cubes are clear and colorless. Bowls are now ¾ way full.

6. Steam begins to continuously stream out of both cans.

7. Plastic tongs are used to lift the first can. Can is then placed right side up in one of the bowls of ice water.

8. Leftover water in can quickly evaporates.

9. Same plastic tongs as used in step 7 are again used to pick up the second can. Can is turned upside down and quickly placed in the second bowl of ice water.

10. Can implodes with a very loud “bang”. After being lifted out of the bowl, a small amount of water spills out into the bowl.

11. Imploded can is kept in experimenters room while the undamaged can is thrown in the trash can, water and ice are dumped into the sink, and stove is turned of.

E. Conclusion:

The hypothesis above was confirmed. The experiment itself did not contain any noticeable faults. The steam in the aluminum can pushed out all of the air outside of it. The experimenter can conclude that because of the fact that there was no air in the can, it imploded as a result of atmospheric pressure forcing the aluminum inward. The experimenter may also conclude that because the air inside of people, humans, and all living things is pushing outward, that there will never be any danger thanks to The Creator's marvelous design for our survival.

This experiment may be improved by adding less water to the aluminum can. In doing so, more air can be removed. The less air in the can, the more noticeable of an implosion there will be. Also, a smaller can would serve as the same remedy for this issue.

Further research may also be tested after performing this experiment. This research could include why the steam in the can helps to remove the air. Also, it is crucial to understand why the water in the bowls must be ice cold. These are two critical components of this experiment that must be recognized.

F. Bibliography:

Rosenoff, Steven. Classroom Lecture. July 7, 2011

Wile, Dr. Jay L. Exploring Creation with Physical Science, 2^nd Edition. Apologia Educational Ministries, Inc. 2007

Wikipedia contributors, “Atmospheric Pressure” Wikipedia, The Free Encyclopedia

Domain: http://en.wikipedia.org/

Document: wiki/Atmospheric_pressure

Universe Today, “Atmospheric Pressure” Universe Today

Domain: http.//www.universetoday.com/

Document: 44400/atmospheric-pressure/