Comparing the Electrical Output of Various Electrolyte

PURPOSE

The purpose of this experiment was to compare the electrical potential of various electrolyte/electrode combinations in a wet-cell battery.

I became interested in this idea when my dad entered a school for H/VAC Technicians.  He taught me how to use a voltmeter.  After that I became more and more interested in batteries.  

The information gained from this experiment could benefit battery producers.  They need to know which electrolyte they should add to a wet-cell battery so that it will give the greatest electrical voltage. 

HYPOTHESIS

My hypothesis was that the zinc and copper wet-cell battery would produce more electrical voltage. 

I based my hypothesis on the fact that everyday batteries are made of a zinc-copper mix.  This lead me to believe that producers use zinc and copper in the batteries that they produce because they have the best performance compared to other combinations.

EXPERIMENT DESIGN

The constants in this study were:

• Amount of electrolyte

• Size of test tube

• Size of zinc and copper strips

• Number of strips

• Size of wires

• Length of wires

• Voltmeter

The manipulated variable was the electrolyte and electrode combinations I was testing. 

The responding variable was the electrical potential, in volts, of the different liquids I used.   

To measure the responding variable, I used a voltmeter to find the amount of volts the battery produces.   

MATERIALS

        

QUANTITY	ITEM DESCRIPTION
2	copper strip
2	zinc strip
2	lead strip
2	porous cup
2	250mLbeaker
150 mL	Zinc Nitrate solution
150 mL	Copper Nitrate solution
150 mL	Lead Nitrate solution
1	voltmeter
1	pair of safety goggles
1	apron
1	pair of gloves
1 sheet	fine-grain sandpaper (220 grit)

 

PROCEDURES

1. Put on rubber gloves, apron, and safety goggles.

2. Clean zinc, copper, and lead strips with fine-grade sandpaper to remove outside coating.

3. Place about 75mL of zinc nitrate solution in a 250mL beaker.  Immerse clean zinc strip in solution.

4. Fill porous cup with about 2 cm of copper nitrate solution.  Immerse clean copper strip in solution.

5. Connect one wire to the zinc metal and the other to the copper metal.  Connect each wire to voltmeter.

6. Lift up and touch porous half-cell to the beaker’s solution to see if the battery is hooked up properly.  The needle should deflect to the positive side of the meter.  Switch the wires if the needle shows a negative deflection.  

7. Place porous cup in beaker and immediately read meter.  Record voltage in table. 

8.  Repeat for 10 trials.

9. Prepare lead half-cell in another beaker by pouring 75mL of lead nitrate solution in 250mL beaker.  Clean copper strip thoroughly and rinse outside of porous cup with distilled water.  Immerse copper cup in lead solution.  Record voltage in notebook for 10 trials.

10. Change porous cups and set up zinc half-cell in porous cup by filling it 2cm with zinc nitrate solution.  Place clean zinc strip in porous cup.  Immerse zinc cell in lead nitrate solution.  Repeat for 10 trials.

11. Clean-up area and wash materials with distilled water.    

RESULTS

The original purpose of this experiment was to compare the electrical potential of various electrolyte/electrode combinations in a wet-cell battery.

 The results of the experiment were that the lead-copper cell had the greatest electrical potential with an average of 483.6 mV.  The zinc-copper cell had the least with an average of 93.8 mV.  The lead-zinc cell was a high second with 421.1 mV.

CONCLUSION

My hypothesis was that the zinc and copper wet-cell battery would produce more electrical voltage.

The results indicate that this hypothesis should be rejected, because the zinc-copper cell has the lowest voltage.  The lead-copper cell performed the best. 

Because of the results of this experiment, I wonder if the temperature of the electrolytes/electrodes would affect the voltage. I wonder if a more concentrated electrolyte would produce more electrical output.  I also can’t help but wonder if the size of the electrodes would affect the voltage it produces.

My findings should be useful to battery producers because my results show that lead-copper produce more voltage than anything else I tested.

If I were to conduct this project again, I would use more combinations of electrolytes and electrodes.  I would also conduct more trials for each combination to receive more reliable results. 

Researched by --- Kevin B. 

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Effect of Acid Rain on the Biomass of Radishes

   

PURPOSE

The purpose of this experiment was to determine the effect of acid rain on the biomass of radishes.

I became interested in this idea when my family started to plant a garden. We watered, fertilized and weeded the plants. Not all of the plants grew. They died within a week or two. I wonder it could have been caused by acid rain. My parents also told me once how the rain may be affecting the crops. They told me about some chemicals that get in rain.

The information gained from this experiment could help gardeners and farmers with their crops. It could also help warn those who might contribute to acid rain, such as, factories, truck-drivers, and others who drive a automobiles.

HYPOTHESIS

My first hypothesis was that the plant’s biomass would be less as the water pH decreased (became more acidic). 

My second hypothesis was that the survival rate of the radishes would decrease as the pH decreased.

I based my hypotheses on a book “Acid Rain” by Gail B. Stewart.  It stated, “In the last twenty years, rain has been associated with other, less pleasant ideas. Scientist, especially those who study the environment, has found that not all rain and snow are pure. In whatever form, much of the water that comes from the sky is laced with deadly chemicals that turn into acid. The acid builds up in lakes and rivers. It kills the fish and insects that live in the water. Acid rain has also damaged many of our forests. It is harmful to some crops. There is also more and more evidence that acid rain is hazardous to human beings.”

                                                EXPERIMENT DESIGN

The constants in this study were:

•    The number of radishes in each group (36).

•    Number of seeds in each cell (2).

•    The amount of liquid given to each plant.

•    When each plant is watered when needed.

•    The depth the seed is planted in the soil (1 cm).

•    The distance each light is from the ground (30cm).

•    The amount of time each plant gets light (14 hr 6:00am-8:00pm).

•    The temperature each plant grows at (76ºf, 24°c). 

The manipulated variable was the pH level in the water given to the different groups of plants.

The responding variable was the plant growth (mass) of the radishes.

To measure the responding variable, I used a triple beam balance to weigh the plants after they were uprooted.

    

MATERIALS

QUANTITY	ITEM DESCRIPTION
288	Early Scarlet GLobe radish seeds used (144 for experiment)
4	Syringes (12 ml)
2	"Easy Grow" planters (72 cells)
2	Bags of potting soil
2	Fluoresent Lights and fictures
1	Triple beam balance
1	Greenhouse (L76cmx W601cmx H86cm)
4	Plastic bottles
4	paper bowls
1	Light Timer
1	Pencil marked at 1 cm

                                                             PROCEDURES

I.    Prepare soil in planting containers

A    Put enough soil in each planter cell, evenly, so that each cell has soil      up to the top.

B    Shake planter and tamp it on a counter so that the soil is loosely packed.

C    Sprinkle more soil on the cells so that there is soil until the planter cells are filled to the rim.

D    Put water in a paper bowl and pour water in each cell. Water each planter cell individually, so they are slightly soaked.

E    Repeat this step if soil is not fully wet.

F    Add more soil until cell is filled to the rim of the planter.

G    Repeat steps above for the other trays that you may have.

II.    Plant Radish seeds in planter

A    Mark a pencil 1cm from the tip.

B    Make 2 small holes in soil diagonal from each other to the 1 cm mark.

C    Put 1 seed in each hole.

D    Put each seed into its hole, 1cm deep.

E    Cover the seeds and pat the dirt lightly onto the seeds.

           

III.    Water the plants

A    Check the bottom tray for water.

B    Check the soil and see if it is dry 

C    Always water every cell with the same amount and at the same time (depending on how much they need).

IV.    Mixing the pH levels  

A    Ask a local laboratory to mix 4 different water pH levels.

B    They used distilled water (H2O) and added sulfuric acid (H2SO4) to make different levels of acid rain.

C    They made pH levels 6.0, 5.0, 4.0, and 3.0 and labeled them.

D    Label groups of 36 plants as “6.0,” “5.0,” “4.0,” and “3.0”.

V.    Treat plants with pH levels

A    Repeat the step three of watering the plants except.

While giving the plants toxins check on them daily for: Health, Growth, Color changes, and Leaves.

VI.    Measure Plants for Biomass:

A    Pull each radish plant carefully out of its planter cell and remove dirt.

B    Weigh all plants from group together on Triple Beam Balance 

C    Count plants in this group and divide the mass by the number of plants to get the average.

D    Repeat these steps until each group has been done.

RESULTS

The original purpose of this experiment was to determine the effect of acid rain on the biomass of radishes.

The results of the experiment were that the pH level of 6.0 groups was the healthiest group in biomass by a large amount and the group 5.0’s biomass was the least. The pH level of 6.0’s group biomass averages are 0.27g. 5.0’s were 0.23g. 4.0’s were 0.25g. 3.0’s were 0.24g.

    

CONCLUSION

My first hypothesis was that the plant’s biomass would be less as the water pH decreased (became more acidic). 

The results indicate that the overall pattern was for plant mass to decrease as pH decreased. However one group, the 5.0 pH group, did not follow the pattern and had the smallest average biomass. For this reason, my first hypothesis should be rejected, until more research is done. 

My second hypothesis was that the survival rate of the radishes would decrease as the pH decreased. 

The results also indicated that my 2nd hypothesis should be rejected because all the groups survived at an equal rate. 

After thinking about the results of this experiment, I wonder how acid rain would affect different plant species such as soybeans or tomatoes.

If I were to conduct this project again I would do several things differently. I would have used 2-3 times more plants. I would have used a more accurate scale so that I would have more accurate results. I also would have tested my seeds before planting to make sure the germination rate was near 100%. I also would have grown them in the sunlight in late spring.

Researched by -  Kaitlin B

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Effect of Football Helmet Padding Pressure on the Effect of Force of Impact

PURPOSE

The purpose of this experiment was to determine if air pressure in a football helmet’s padding affects the force of impact. 

I became interested in this idea after the football team I played on had won our championship game. I wondered if playing football that season had made any effect on my brain, good or bad.

The information gained from this experiment could possibly be helpful for football players and coaches in all different leagues, letting them know the effect their helmet has on possible brain injury.

HYPOTHESIS

My first hypothesis was that the impact force would decrease as air pressure inside the padding increased from 0 mm Hg (totally empty) up to 200 mm Hg (maximum tested). 

My second hypothesis was that the impact force would increase as air pressure inside the padding increased above 75 mm Hg.

I based my hypothesis on the answer my football coach gave to the question, “Is the air pressure in the padding for comfort or for fit?” My coach answered, “It is for both. It depends on what the player wants. Some people like it as pumped up as they can get it, other like it as empty as possible.”

EXPERIMENT DESIGN

The constants in this study were: the helmet being tested, size of mannequin head, way tested, force/speed of helmet at impact, the temperature at which the experiment was conducted, the measure being used, accelerometer probe being used, and the software that read the probe.

The manipulated variable was the pressure in the football helmet.

The responding variable was “g” force or force of impact.

To measure the responding variable I used a Vernier Accelerometer probe attached to a computer running Logger Pro 3.0 software, which reads “g” force of the impact/ collision 

MATERIALS

QUANTITY	ITEM DESCRIPTION
1	Vernier accelerometer probe
1	computer running Logger Pro 3.0 software
2	football helmet
1	hand pump (off of a blood pressure cuff)
1	pulley
1	Mannequin head
25	Feet of 1/8inch rope
1	roll of masking tape

 PROCEDURES

1. Tie a rope securely to the base of the pulley.

2. Pass the rope over a strong support 3 meters above floor.  Pull the rope so the pulley is positioned securely about 3 meters above the floor.  

3. Take a helmet and tie it to a second rope.

4. Run this rope though the pulley so the weight can be raised and lowered easily.

5. Attach the Vernier accelerometer probe to the computer with Logger Pro software.

6. Place the Vernier accelerometer probe inside the mannequin head shape by drilling a hole in the top of it and stuffing the probe inside of the hole.

7. Using bulb pump from a sphygmomanometer attached to a sports ball needle, add air to the internal protective pad in the football helmet.  The pressure should read 0 mm Hg.

8. Put the mannequin head shape into the helmet in an upright position on a flat surface that the masking tape can fasten the mannequin head into a position where it is not tilted or uneven when it is placed on the flat surface. 

9. Be sure it is positioned exactly under the other helmet.

10. Check helmet for correct fit.

11. Hold the rope so the helmet is in a fixed position, suspended 2.0 meters in the air directly above the helmet with the mannequin head. The empty helmet must not be swinging.  

12. Release the rope so the weight will hit the helmet and mannequin head. 

13. Record what the Vernier accelerometer probe reads in “meters per second squared” for that individual helmet brand at the moment of impact.

14. Repeat steps 10-13 for a total of 10 trials.  

15. Repeat steps 8-14 for each pad pressure.

  

RESULTS

The original purpose of this experiment was to determine if air pressure in a football helmet’s padding affects the force of impact.

The results of the experiment showed that the impact impulse raised as the air pressure inside the helmet increased. The maximum impact was similar on average for all pressure levels. 

                                                          CONCLUSION

My first hypothesis was that the impact force would decrease as air pressure inside the padding increased from 0 mm Hg (totally empty) up to 200 mm Hg (maximum tested).

My second hypothesis was that the impact force would increase as air pressure inside the padding increased above 75 mm Hg. 

The results indicate that my first hypothesis should be rejected. 

The results indicate that my second hypothesis should be accepted.

Because of the results of this experiment, I wonder if not having the padding in the helmet helps with the impact force.

If I were to conduct this project again I would b sure to do so in a more controlled manor. I also would find a something different do set the probe into instead of using a Styrofoam mannequin head. I believe that the Styrofoam head had a bad affect on the results of this experiment.

Researched by -- Camdon A. 

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