Experiment 2: Capacitor Bottle Shapes

Using the results of the previous experiment, we set out to determine which bottle shape matched our goals the most.

Purpose:
The purpose of this experiment is to determine which of two types of bottle shape (tall and thin or short and fat) would meet our criteria of high capacitance and ease of preparation.

Hypothesis:
The group's hypothesis was that the taller, thinner bottle shape would meet our criteria the best because of the narrow radius of the bottle, the high surface area of the exterior, and the affordability of the drink that came with it (orange cream soda).

Variables:
Control
Concentration: All salt-water used in this experiment is 26.9 g / 300 mL of water.
Liquid: We chose to use 300 mL ± 1 mL of pure deionized water.
Salt: We chose to use "Diamond Crystal Kosher Salt" as our salt.
Foil: We chose to use "Reynolds Wrap Quality Aluminum Foil" as our foil.
Oil: We chose to use "Arco Supreme Motor Oil" as our oil.

Varied:
Bottle shape: We chose a tall and thin bottle and a short and fat bottle.
Oil: We chose to place oil nowhere in the system, only in the capacitor bottle, and in the bottle and tub at the same time.

Equipment:
Today's experiment used the following materials:

• 2 200 mL beakers to hold salt in (120 g each)
• 1 500 mL graduated cylinder
• 1 orange cream soda bottle, cleaned thoroughly
• 1 short and fat bottle, cleaned thoroughly
  
• Aluminum foil
• Kosher salt
• Deionized water
• Weights and mass measuring devices
• Funnel to aid pouring of salt
• Motor oil
• Large plastic bin
• Electric tape
• Multimeter

Procedure:

1. We wrapped the interior of the bin with two layers of tin foil, sealing the edges with electric tape and prepared the two bottles with foil and lids.
   
2. We filled both bottles with 300 mL of our salt-water.
3. We placed the bottles, and a few more bottles purely for displacement purposes, into the bin.
4. We filled the bin with 7000 mL of the salt-water, which used up our cache of salt.
5. We placed one probe on the foil lining the bin and one probe on each bottle's conductive core using the multimeter. We measured the resulting capacitance.
6. Repeat step 5 with motor oil only in the bottle and motor oil in the bottle and the surrounding fluid to detect any changes in capacitance.
   

Results:
Table 2.1: Capacitor bottle shapes and capacitance

Bottle	Oil	Ratio of Salt to Water	Capacitance (nF) ± 1 nF
Tall and Thin	None	26.9 g / 300 mL	2
	Bottle only	26.9 g / 300 mL	2
	Bottle and tub	26.9 g / 300 mL	2
Short and Fat	None	26.9 g / 300 mL	2
	Bottle only	26.9 g / 300 mL	2
	Bottle and tub	26.9 g / 300 mL	2

Analysis:
The results show that the salt water capacitors are not affected by the size to a measurable amount with our techniques. Since this makes the capacitance of our criteria equal, the only difference between the two bottle shapes is the ease of preparation. Since the group immensely enjoyed purchasing the economically affordable orange cream soda and then drinking it, as well as wrapping the bottles in foil, the group has decided that the tall and thin bottles (the orange cream bottles) are the chosen bottles for our capacitors.

Because the oil status did not affect the capacitance directly to a measurable amount with our techniques, we are going to rely on our understandings of the motor oil's purpose to make that decision. From what our research has suggested, ionized salt water (which would be created in the process of charging our capacitors) creates 03 in contact with the air, which is a volatile and toxic gas. To reduce the risk of spontaneous explosions from the capacitor, we are using the motor oil to act as a barrier between the atmosphere and the salt water.

Further questions include what type of motor oil to use, specifically detergent or non-detergent. We also want to understand the relationship between salt-water concentration and capacitance in more detail.

Attendees:
Nate
Dan
Eric
Jodi
Matt

Experiment 1: Salt Water Capacitor Concentration (cont.)

We continued the capacitor experiment now that the four solutions and bottles were prepared. The testing procedure was especially easy, but had surprising results.

Note: links are pictures

Procedure:

1. Placing one probe on the conductive screw and one on the exterior foil, use the multimeter to measure the capacitance of the four different concentrations.

2. Use two new concentrations of salt water to refine data, placing their concentration near the highest capacitance solution's concentration.

Results:

Table 1.1: Salt-to-water ratio and capacitance

Bottle	Ratio of Salt to Water	Capacitance (nF) ± 1 nF
1	26.9 g / 300 mL	2
2	53.9 g / 300 mL	1
3	80.8 g / 300 mL	1
4	107.7 g / 300 mL	1
5	20.0 g / 300 mL	1
6	10.0 g / 300 mL	1

Analysis:

According to the data gathered, the 26.9 g / 300 mL had the highest capacitance. This was contrary to our hypothesis, and we plan to delve further into the theory as to why this is true. Current ideas suggest that the lower salt-water concentration allows the ionized particles to move with more freedom. We are searching for a more definite answer.

We want to have a more definite and precise method to measure the capacitance of these capacitors. The multimeter gave the measurement to the nearest nF, without a decimal point. This made determining the pattern of concentration to capacitance difficult, since we only have two levels (1 and 2 nF) of capacitance. I will search for a more accurate tool.

Using this result, the group began the next phase of our capacitor experiments.

Experiment 1: Cont

On Friday, myself and a few students showed up to the club. Due to the lack of major attendance, we created the solution for the remaining two bottles and began planning how to construct the conductive lids. Sadly, that Friday was not a productive one.

Experiment 1: Salt Water Capacitor Concentration

Today, we started our first experiment: Salt Water Capacitor Concentration.

Note: links are pictures

Purpose
The purpose of this experiment is to discover the ideal concentration of kosher salt to pure deionized water for peak capacitance for the tesla coil.

Hypothesis
The group's hypothesis was that the highest concentration of salt would be ideal since it is the most conductive.

Variables
Control
Bottle Shape: We chose to use the orange cream soda bottle for this experiment. The bottle was rinsed out and cleaned using deionized water and soap. The soap was rigorously cleansed from the bottle.
Liquid: We chose to use 300 mL ± 1 mL of pure deionized water.
Salt: We chose to use "Diamond Crystal Kosher Salt" as our salt.
Foil: We chose to use "Reynolds Wrap Quality Aluminum Foil" as our foil.
Oil: We chose to use "Arco Supreme Motor Oil" as our oil.

Varied
Concentration: We chose to use four different masses of salt to put into 300 mL of the liquid: 107.7 g, 80.8 g, 53.9 g, and 26.9 g.

Equipment
Today's portion of the experiment involved the following equipment:

• 4 200 mL beakers to hold salt in (120 g each)
• 1 500 mL graduated cylinder
• 4 orange cream soda bottles, cleaned thoroughly
• Aluminum foil
• Kosher salt
• Deionized water
• Weights and mass measuring devices
• Funnel to aid pouring of salt

Events
We focused on preparing and creating the capacitors instead of testing the capacitance. We had split the attendees into different tasks related to this.

The following are the chosen tasks:

• Chemical capacitor theory
• Cleaning bottles
• Placing foil on bottles
• Gathering equipment
• Measuring salt
• Measuring water
• Combining salt and water

Procedure

This is how the day's events went.

1. We gathered after finding someone who could unlock the lab.
2. Once we obtained the desired equipment, we began drinking the orange cream soda in order to use the bottles.
3. We began cleaning the bottles and splitting up the tasks.
4. The salt measurers measured four different masses of salt, to a very accurate degree with an electric measuring device:
• Sample 1: 26.9 ± 0.01 g
• Sample 2: 53.9 ± 0.01 g
• Sample 3: 80.8 ± 0.03 g
• Sample 4: 107.7 ± 0.1 g
5. The foil wrappers wrapped two layers of aluminum foil over the bottle, leaving about 1 cm of space from the top to prevent conductivity from the foil to the cap.
6. Two people left to purchase the following items for later in the experiment:
• Motor oil (30W non-detergent)
• Tub, plastic (or other container; may need to hold partial vacuum)
• Electrical tape
• 1/4 x 6" galvanized carriage bolts (1 per bottle)
• 1/4" nuts (2 per bolt)
• Funnel
7. While the two people left to purchase goods, we poured 300 mL of deionized water into the two prepared bottles and put into bottle 1 the sample 1 salt and into bottle 2 the sample 2 salt.

We ran out of time to continue the experiment, which means that we should finish up creating the capacitors next week and begin measuring capacitance.

Meeting Minutes

Today, we did not discuss a lot about the future of the project compared to last week. The main topic of discussion was the capacitors. We decided to use motor oil to seal the salt water off. This prevents the creation of ozone caused by ionized salt water. Also, we were discussing putting the six planned capacitors into a vat or container of salt water with similar concentration. This, according to a theoretical discussion, would enhance the capacitance of the entire six pack. We may need to experiment with this. We also discussed the possibility of removing as much air as possible from our capacitor container to prevent disruption like particles landing in our solution. We do not think a total vacuum would be appropriate, due to the extreme pressure differences and structural integrity.

Attendees

· Dan

· Eric

· Jodi

· Joe

· Matt

· Nathaniel

· Robert