The purpose of this experiment was to determine the pH level in various
types of soda pop.
I became interested in this idea when I was drinking a soda and I
wondered what caused its tart taste and acidy fizz.
The information gained from this experiment could help consumers know
what kind of soda pop to buy that won’t destroy their bone calcium and
tooth enamel as much as others.
My hypothesis was that colas like Coca-cola or Pepsi would have lower
pH than the other pops.
I based my hypothesis on a website http://web.ask.com by Bob Peebles at
that said, “Coca-Cola classic is the most acidic beverage at around
The constants in this study were:
- The amount of soda-pop in each container
- The type of pH measuring meter
- Container the soda is put in
- How long the meter is put in the soda
- Type of container the pop was held in
The manipulated variable was the kind of soda pop.
The responding variable was the pH level.
To measure the responding variable I used a digital pH-measuring meter.
(355 ml.) Coca-Cola
(355 ml.) Pepsi cola
(355 ml.) Mountain Dew
(355 ml.) Sprite
(355 ml.) Orange soda
(355 ml.) Root Beer
1. Collect items for experiment.
a. Three cans each of Coca-Cola, Pepsi, Mountain Dew, Sprite, Orange
soda, and Root Beer.
b. Digital pH measuring meter
c. Measuring cup (ml)
2. Label each group of three pops a-f.
3. Take a can from group A and measure out 100 ml. of the pop in a
4. Next put pH meter in the soda pop that’s in the measuring cup and
wait for about ten seconds. After the numbers stop changing, read
meter. Record data.
5. Triple test each can, so do this test two more times.
6. Repeat step 3 - 5 for the rest of the cans in-group A.
7. Average the results for all the cans in this group.
8. Repeat steps 3 - 7 with another group like B.
9. Repeat steps 3 - 7 for the rest of the groups C - F.
The original purpose of this experiment was to find the pH levels in
various types of soda pops.
The results of the experiment were that Root Beer had the highest pH at
4.24 followed by Sprite at 3.29 and Mountain Dew at 3.27. The
lowest scores were Orange at 2.90, Pepsi at 2.61, and the one with the
lowest pH was Coca-Cola at 2.52.
See the table and graph below.
My hypothesis was that colas like Coca-Cola or Pepsi would have lower
pH than the other pops.
The results indicate that this hypothesis should be accepted because
Coca-Cola and Pepsi had lower pH than all the other pops.
Because of the results of this experiment, I wonder if the amount of
carbonation would affect the amount of pH. For example, if the
pop was forced to be “flat” would that affect the pH.
If I were to conduct this project again I think I should use the
reference solution for the pH meter more often to make sure it was
still reading right during the experiment.
I also could have tested more brands of pop to tell the pH of other
pops that people might like, for example Shasta pops and Sam’s Choice.
I should have tested different types of pop like Mountain Lightning,
which is almost the same as Mountain Dew and I should have checked for
One really important health need of humans is healthy bones. When
consumers drink pop with very low pH it affects their bone calcium.
Bones are made by body cells. Bones are living organs.
That’s why bones can mend themselves and make blood. Bones are
always making new cells. To do this calcium is stored in bones
through the blood. When you are young you grow quickly that’s why
kids need a lot of calcium. It is vital that kids eat
calcium-enriched foods and not pop. In later life you don’t need
as much. Calcium carbonate makes teeth hard. If the outer
layer of a tooth called the enamel is destroyed it can’t be replaced.
When people drink pop it robs bone calcium. The bone calcium is
turned into alkaline by your body to neutralize the pH in pop.
Humans need calcium for bone growth and strength. Pop robs the
calcium you need for your skeletal system. If you don’t have
calcium, your bones can get weak and you can get hurt more easily.
In isolation calcium is really a metal. The most common compound
is calcium carbonate. Bones of animals and humans have calcium in
them. One-fifteenth of the human body is calcium.
Calcium is never found on it’s own because it reacts with other
elements easily. Limestone is the most common calcium
holder. Calcium is precipitated in springs because it isn’t
stable in hot water. Building stones have calcium in them.
Calcium oxide is in cement or in concrete known as quicklime.
Calcium hydroxide is hard and white.
The pH is a number showing the amount of hydrogen ions in a
solution. pH stands for potential hydrogen. The scale is
0-14. Something with a pH level of 7 is totally neutral, neither
acidic or basic. Distilled water has a pH around 7. A pH of 0 to
almost 7 in the scale is acidic. From 7 to 14 is alkaline on the
scale. A pH lower than 3 can give brain damage to people.
Human blood is about 7.4 pH.
The pH is expressed as moles of hydrogen ions per liter. A pH
solution with 6 is 10-6 (or one millionth) of a mole of hydrogen
ions. A chemist Soren Sorenson made the pH system in 1909.
There are about two ways of measuring pH. One way is with a pH
meter or using special strips that change color depending on amount.
Phosphoric acid is one of the acids in soda pop; its formula is
H3P4. Phosphoric acid is also called orthophosphoric acid. This
acid is very soluble (dissolves) in water and alcohol. It is made
from phosphate and sulfuric acid. It also melts at 42.4°
Celsius. This acid is also helpful as a water
Citric acid is another acid in pop. It is a very weak acid if it
wasn’t it could take a couple teeth out. Its formula is
C6H8O7. Citric acid is in many fruits that are commonly known as
citrus fruits like oranges, limes, lemons, and many others. The
citric acid in fruit is what gives fruit sourness. It is also
found that molds can produce this acid. This acid melts at
153° Celsius. Citric acid shares the same properties as
carboxylic acid. Citric acid is used for flavoring such as in
pop. Citric acid is what gives fruit tartness. Citric
acid is also used as water softener. Citric acid is popular as a
Carbonic acid is made from carbon dioxide and water mixed which equals
the formula H2O + CO2 = H2CO3. It is also impossible to get pure
carbonic acid. To get carbonic acid; carbonation in pop it is
pushed in at 250-550 kilo pascals.
A soft–drink is a flavored, non-alcoholic, carbonated
drink. Soft drink indicates that pop is not an alcoholic
drink. On average people drink about 56 gallons a year.
Joseph Priestly made the first carbonated drink. In 1772 a
British scientist found a way to force carbon dioxide into water.
That’s what carbonated water is. This led to the soft-drink
industry. In the 1820’s soda was first put in refillable
bottles. In 1905 the crown cap was first used for
Coca-Cola is called the world’s greatest soft drink. John
Pemberton made the original formula for Coca-Cola. Pemberton’s
partner made the name “Coca-Cola” because he liked two C’s. It
was a tonic for headaches and tiredness. He sold 25 gallons for
$50. Their slogan was “Delicious and Refreshing.” One day
someone spilled carbonated water in the mix and everyone liked it
better. Soon he sold the business to a man named Asa Candler for
$2,300 because of health.
Candler made Coke very popular in the United States. His
slogan was “Nerve and Brain Tonic.” He advertised Coke on
calendars and many other things. Mr. Candler didn’t like bottling
but let a fountain owner do it so he could sell to people out of the
city. Many tried to copy the drink. There were 150
imitators. In 1915 Asa hired a man to make a curved glass like a
bell. In 1919 Candler sold Coca-Cola to a group of
investors for $25 million. They elected Robert W. Woodruff as
president of the company. In 1920 Woodruff had cola put in
vending machines so people could get one for themselves. Today
the Coca-Cola company produces many other products like Sprite.
Here are some interesting facts:
∑ Mexico and Iceland have the highest per capita consumption of
∑ Every second over 7,000 Coca-Cola products are consumed.
∑ If all the Coca-Cola vending machines in the U.S. were stacked one on
top of each other, the pile would be over 450 miles high.
∑ This is what’s in Coke: carbonated water, high fructose corn
syrup, caramel coloring, phosphoric acid, natural flavors, caffeine.
Pepsi Co, Inc. is a big company. Bottles are shipped around the
world. In 1889 Caleb Bradnem made the first Pepsi drink. It
was originally made to cure dyspepsia. Caleb formed the Pepsi
Company in 1903. He bottled the product and filled drugstores
with it. In 1923 Bradnem filed for bankruptcy because of bad
sugar prices. In 1931 Charles G. Guth bought the company.
Guth increased sales by selling larger bottles. Pepsi has grown a
lot since 1933. Pepsi became the second best seller in the pop
industry. Former Coca-Cola worker Alfred Steele was Pepsi’s
president in 1950. Pepsi obtained Mountain Dew in 1964.
Pepsi also owns and sells bottled waters, sport drinks, and ice
Bone calcium is very important to human health. The pH in pop
robs that and tooth enamel. Pop does that because of all the
acids in it. So if you have a craving for pop you should think
about all the harm it can do. When you lose too much bone calcium
you can get hurt. As a child it is even worse to drink pop
because you need more calcium to grow up. When you drink pop it
takes enamel and your tooth can’t replace it so your tooth suffers.
Armbruster, David C. “Citric Acid”.Nov.04.
Barratt, Robert F. “Soft Drink Industry.” Canadian Encyclopedia. 1998.
Busch, A Marriana. “Phosphoric Acid.” World Book Encyclopedia. 1999.
“Carbonic Acid”. Nov. 04.
“Carbonic Acid”. 11/24/04.
Chamblee, Theresa S. “Soft Drink”. 20, Oct. 2004.
“Citric Acid.” 17 Nov. 04
“Citric Acid”. 12/1/04. http://www.factmonster.com.
Columbia University Press. “Phosphoric Acid”
“Coral Calcium”. Soda pH. 11/16/04.
Melissa Maupin. Coca-Cola. Mankato, Minnesota. Smart Apple Media,
2000. 4-32, 42-48.
“Pepsi Co, Inc”. Encarta. 2005.
“Phosphoric Acid.” The Columbia Electronic Encyclopedia. 2004.
“Phosphorus”. Elements. 1997. Vol.11. Pp.42-50.
I would like to thank the following people for helping make my project
- My mom for helping me to do my experiment and
supporting me in what I do.
- Mr. Newkirk for teaching me things to do and how to
improve and also correcting my report.
- Melinda Simon for taking two hours out of her time at
Tree Top to let me do my experiment.
- Mrs. Helms for helping me and finding mistakes in my
Top of page
Menu of 2004-2005 Science Projects
Back to the Selah