Bethanie

**Title**
Bacteria

**A. Question / Problem**
Do canines or humans have more bacteria in their mouths?

**1. intro**
I want to test if canine's or people will have more bacteria in their mouths. I want to check them after forty eight hours and see which one has more bacteria.

**B. Hypothesis**
My hypothesis is that humans will have more bacteria because dogs have a cleaning thing is their mouths. That cleaning thing takes most of the germs and bacteria and just cleans out their whole mouths and humans do not have that.

**C. Method / Procedures**
Boiling water. Waiting 48 hours for bacteria to grow.

= =

**1. Step by Step**
Collect dog saliva and human saliva. Put both cotton swabs in two different test tubes. Write on the petri dishes which bacteria it is. Boil hot water. Put boiled water into completely clean petri dish with agar. Wait until the agar in water is room temperature. Make three or four "S" lines in the water. Wait 48 hours for the bacteria to grow. Look at the bacteria and see which petri dish has more bacteria in it.

**2.** Materials
cotton swab test tube petri dish boiled water agar water crayon

**3. Analysis**
There is different bacteria in a dogs mouth than a human's mouth. I learned how to make an agar plate.

= =

The dog's mouth had more bacteria in it. The human's mouth was more clean.

**Research:**
Saliva is the watery and usually full of substance that is produced in the mouths of humans and most animals. Human saliva is composed of about ninety nine percent water while the other is one or two percent of other compounds such as mucus, antibacterial compounds, and various things. As a part of the food digestion, the enzymes in the saliva break down some of the starch and fat in the food. Saliva also breaks down food caught in the teeth, protecting them from bacteria that causes cavities. Saliva protects the teeth, tongue and the tender tissues inside of your mouth.
 * Saliva**

Saliva also is important for tasting food by trapping thiols produced from odorless food compounds by anaerobic bacteria living in the mouth. Some swifts use their gummy saliva to build their nests. Some nests are made only from saliva and used to make birds nest soup. Cobras, vipers, and certain other members of the venom clade hunt with venomous saliva injected by fangs. Some arthropods, such as spiders and caterpillars, create thread from salivary glands.

A dogs mouth might actually be cleaner than a human's mouth. If a person bit another person that would mean that person could get more infected then if that person got bit by a dog. The bacteria in a dog’s mouth is different from the bacteria present in a human’s mouth. So when you’re dealing with different bacteria, it’s difficult to make this sort of comparison. It’s a difficult comparison to make due to the vast differences when it comes to the mouth’s function and differences in hygiene that exist between humans and canine's. Dogs have some sort of protection in their mouth that can reduce or get rid of germs.
 * Dog Saliva**

Because mouths are warm and wet which are ideal conditions (Bacteria require water for growth and they multiply faster in warmer conditions). Also the mouth contains a lot of nutrients for bacteria from the food which passes through the mouth. Lastly, the mouth is exposed to food and the environment which contain many bacteria.
 * Bacteria**

To thrive, bacteria require a source of food, possibly oxygen depending upon the species, water, and warm temperatures. All these are consistently found in the mouth. However, there are also negative factors that control just how many bacteria can thrive at a given time. these include: there natural life span, chemicals found in saliva, swallowing which moves bacteria from the mouth to the stomach which is very acidic which kills off many bacteria.

We all have bacteria in our mouths. The bacteria that cause tooth cavities could be considered harmful. This is why you should brush your teeth after eating and not eat too many sweets which they also love. Every time you open your mouth bacteria gets in. As long as you don't have an open wound in your mouth, you are probably o.k. because most of the time the bacteria gets swallowed and killed by the acid in your stomach. You also have enzymes in your mouth that can kill bacteria. Most of the bacteria in your mouth however cause you no harm, and may even help you because they take up space and crowd out bad bacteria that are trying to find a place to live.

There are many different types of bacteria in your mouth every second. These are called normal flora. Some examples of normal flora in your mouth are Streptococcus salivarious, Streptococcus mutans, and Actinomyces. Different types of bacteria can grow in very different ways. Some require oxygen and some will not grow when oxygen is even there. The bacterium //Streptococcus salivarious// does require oxygen to grow and it gets itself nutrients from many of the things that people eat as an everyday thing. A example of an bacteria that is anaerobic is Actinomyces and it probably is in between the teeth where oxygen comes and goes because it needs oxygen.

The other organism was Streptococcus mutans. This organism is the cause of tooth cavities. When you eat a lot of sugar this bug becomes very happy. It uses the sugar for growth and produces lots of acids that can destroy the tooth enamel.


 * Sites**

Calder, Vince. " Mouth and Bacteria ." //NEWTON/ANL Home Page//. Vince Calder, n.d. Web. 19 Jan. 2010. .

McDougal, Debra. "Can Dog Saliva Kill Bacteria? - Associated Content - associatedcontent.com." //Associated Content - associatedcontent.com//. Debra McDougal, 14 Aug. 2009. Web. 19 Jan. 2010. .

"Saliva - Wikipedia, the free encyclopedia." //Wikipedia, the free encyclopedia//. N.p., 28 Sept. 2009. Web. 19 Jan. 2010. .

Suite 101. "Is a Dog's Mouth Cleaner than a Human's?: Find Out if a Dog’s Mouth is Cleaner or More Sterile." //Mammals//. N.p., 6 July 2008. Web. 19 Jan. 2010. .

"Free Science Fair Projects." //Free Science Fair Projects//. N.p., n.d. Web. 29 Jan. 2010. .