Physical Formal Report Example

Christie W. 09/21/08

Atoms and Molecules

A. Purpose:

The objective of this experiment is to allow the experimenter to gain a greater understanding of how atoms and molecules bond and break. This will be accomplished through the viewing of the reaction between electricity and water containing baking soda.

An atom is the smallest particle that comprises a chemical element. An atom consists of an electron cloud that surrounds a dense nucleus. This nucleus contains positively charged protons and electrically neutral neutrons, whereas the surrounding cloud is made up of negatively charged electrons. When the number of protons in the nucleus equals the number of electrons, the atom is electrically neutral; otherwise it is an ion and has a net positive or negative charge. An atom is classified according to its number of protons and neutrons: the number of protons determines the chemical element and the number of neutrons determines the isotope of that element. The concept of the atom as an indivisible component of matter was first proposed by early Indian and Greek philosophers. In the 17th and 18th centuries, chemists provided a physical basis for this idea by showing that certain substances could not be further broken down by chemical methods. During the late 19th and the early 20th centuries, physicists discovered subatomic components and structure inside the atom, thereby demonstrating that the 'atom' was not indivisible. The principles of quantum mechanics were used to successfully model the atom.

Relative to everyday experience, atoms are minuscule objects with proportionately tiny masses. More than 99.9% of an atom's mass is concentrated in the nucleus, with protons and neutrons having about equal mass. In atoms with too many or too few neutrons relative to the number of protons, the nucleus is unstable and subject to radioactive decay. The electrons surrounding the nucleus occupy a set of stable energy levels, or orbitals, and they can transition between these states by the absorption or emission of photons that match the energy differences between the levels. The electrons determine the chemical properties of an element, and strongly influence an atom's magnetic properties. (Wikipedia)

A molecule is the smallest unit of a substance that shows all the chemical properties of that substance. A molecule is a group of atoms that are bound tightly together by strong chemical bonds called covalent bonds. Every molecule has a definite size. If a molecule is broken up into its atoms or into smaller groups of atoms by chemical processes, these pieces will not behave like the original molecule. A molecule can contain atoms of the same element or atoms of different elements. A substance made up of molecules that include two or more different chemical elements is called a molecular compound. An example of a molecular compound is water. Water is made of molecules that contain two hydrogen atoms and one oxygen atom. See also Atom.

Many substances on Earth are made of molecules. Millions of molecules join together to make up the cells in humans or in any other plant or animal. The food we eat, the air we breathe, the clothes we wear, and the wood, paint, and carpeting that we use in homes are all made of molecules. Millions of different molecules exist in nature or can be made by chemists. The nature of each molecule depends on the atoms that it contains and how they link to each other. For example, the oxygen that animals require is made of molecules that have two oxygen atoms bound together. If one oxygen atom binds to a carbon atom, the molecule is instead the poisonous gas carbon monoxide.

Scientists study molecules and their structures so they can better understand why substances behave the way they do. For example, molecular structure helps explain why water boils at a high temperature. Scientists and manufacturers also use their knowledge of molecules and molecular structures to make substances with desirable properties. Plastics, for instance, are laboratory-made substances that consist of enormous molecules containing thousands of atoms. By manipulating the molecular structure of plastics, chemists have created materials that stretch better, resist fading, or can be used in microwave ovens without melting. Similarly, pharmaceutical chemists use their knowledge of molecular structure to develop new drugs that more effectively ease pain or fight disease. The discovery of the structure of deoxyribonucleic acid (DNA), the molecule that contains the genetic blueprint for living organisms, opened the door to tremendous advances in medicine and industry. Knowledge of the structure of DNA has enabled physicians to understand and treat certain genetic diseases (MSN Encarta). Thus, molecules compose a very important branch of scientific study.

This experiment hopes to show, through the reaction of electricity and water containing baking soda, that molecules and atoms exist and can be viewed breaking and bonding in a home setting, providing the experimenter with knowledge concerning the nature of both atoms and molecules.

Atoms and molecules comprise a vast area of scientific research, and therefore prove to be very important to study, in that most all of creation hangs on these two elements. The understanding of these elements, then, is indispensable, for scientists cannot hope to greatly understand our world if a comprehension of atoms and molecules is not gained.

Hypothesis: If baking soda is placed in the cup of water and the wire and battery successfully conduct electricity into it, and the molecules in the water break down into hydrogen and oxygen, then bubbles will be seen rising from the ends of the wires, and a greater understanding of molecules and atoms will be gleaned by the experimenter.

B. Equipment:

1. A small cup or glass

2. Tap water

3. Baking soda

4. A 9-volt battery (Cannot be an electrical outlet or a flashlight battery)

5. Two 9-inch pieces of insulated copper wire

6. Scissors

7. Electrical tape (Masking tape will work too, but not as well)

8. A stirring spoon

9. Eye protection

C. Procedure:

1. Fill the small glass ¾ full of tap water

2. Add a teaspoon of baking soda and stir vigorously

3. Use scissors to strip about a quarter of an inch of insulation off of both ends of the wire. The best way to do this is to squeeze the scissors around the wire just until the resistance from the wire is felt, then stop squeezing. Do this while several times while rotating the wire after every cut. This will produce the desired results. Make sure that there is at least ¼ inch of wire sticking out both ends.

4. Connect the exposed end of one wire to one of the two terminals on the battery. Do this by laying the wire over the terminal and then pressing it down. Secure it to the terminal with a piece of tape. It need not look pretty, but the bare wire needs to be solidly touching one terminal and not in contact with the other terminal.

5. Repeat step four with the other wire and the other battery terminal. Do not allow the bare ends of these wires to touch each other!

6. Immerse the wires in the baking soda/water solution that is in the small glass so that the bare end of each wire is completely submerged. It doesn’t matter how much of the insulated wire is immersed; just make sure that the entire bare end of each wire is fully submerged. Once again, do not allow the ends to touch each other.

7. Look at the bare ends of the wires as they are submerged in the baking soda/water solution. If everything is set up right, bubbles should come up from both ends of the wires. If bubbles are not seen, the cause is most likely a lack of good contact between the wires and the battery terminals. Try pressing the ends of the wire hard against the terminals to which they are taped. If bubbles come from the submerged end of the wire, then the contact between the wire and the battery was the problem. If not, the battery might be dead. Try another one.

8. Once things are going well, spend some time observing what’s going on. Notice that bubbles are forming on both wires. That’s an important point that should be written down in the laboratory notebook belonging to the experimenter.

9. Allow the experiment to run for about ten minutes. After that time, pull the wires out of the solution and look at the bare ends. One of the wires should not look very different from when the experiment was started. It might be darker than what is was, but that should be it. The end of the other wire should be different, however. Note the color of that wire in lab notebook.

10. If the experiment was successfully run for ten minutes, the water should be slightly colored differently. Note this color also.

11. Note which terminal, positive or negative, the different color wire was attached to. Note this also.

12. Clean up. Disconnect the wires from the battery, dump out the water, wash glass and sink thoroughly, and pick up any other mess that might have occurred during experimentation.

D. Observations:

1. The copper wire and 9-volt battery took a very long time to procure, as these two elements are not common in the experimenter’s household.

2. Once these elements and the cup of baking soda/water are in place, the experimenter places the wires on their respective terminals, securing them with electrical tape.

3. The wires are placed in the water concoction. In doing so the experimenter makes sure that the wire ends do not come in contact with one another.

4. The experimenter notes that the wire connected to the negative terminal gives off many tiny bubbles, while the wire connected to the positive terminal gives off fewer, larger bubbles.

5. The experimenter wonders if the end giving off more bubbles will be the end that discolors most noticeably.

6. Bubbles continue to pour from both ends as the ten minutes tick by.

7. Even after three minutes the positive end begins to discolor to green, a sign that the copper is oxidizing.

8. After the ten minutes are up, the experimenter removes the wires from the water.

9. The results surprise the experimenter. Although the negative end gave off more bubbles, the positive end is the one that changed color.

10. The water did not discolor noticeably, and the experimenter concludes that this is because the glass of water contains too much water for the small amount of electricity and the limited resources to influence the large amount of water contained in the glass.

11. The wire is examined, scratched, and then disposed of, and the rest of the mess is put away.

E. Conclusions:

The above hypothesis was confirmed, in that the baking soda was placed in the cup of water and the wire and battery successfully conducted electricity into it, and the molecules in the water broke down into hydrogen and oxygen, and as a result bubbles were seen rising from the ends of the wires, and a greater understanding of molecules and atoms was gleaned by the experimenter. In the experiment, the copper wire that was used is actually billions of copper molecules that have been formed into a wire shape. When these were attached to the battery, electricity began flowing through the wires because the wires conduct electricity. Then, when the ends were placed in the water, the electricity began to break the water molecules down into hydrogen and oxygen, which then began to bubble up to the surface of the water. The reason that the end of the wire connected to the positive end turned greenish-blue is because the copper atoms in the wire interacted with the carbon molecules in the baking soda and the water molecules, creating a copper hydroxycarbonate.

This experiment could have been improved by using a smaller amount of water, as there was too much used in this experiment. This will allow for the discoloration due to the chemical reactions to be better viewed and understood. Using a smaller glass would fix this problem.

Ideas for further research were generated by the discoloration of one end of the wire. It would be interesting to note exactly why the positive end was discolored while the other end stayed the copper color. This could be achieved by looking into the many resources available on this topic.

F. Bibliography:

Domain: http://encarta.msn.com

Document: /encyclopedia_761563983/Molecule.html

Rosenoff, Steven. Classroom Lecture. October 12, 2008

Wikipedia contributors, "Atom," Wikipedia, The Free Encyclopedia

Domain: http://en.wikipedia.org

Document: /wiki/Atom

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