Every chemical is unique. They have different physical properties, such as texture, colour, and hardness. Chemical properties are the ways chemicals react with one another. For example, sugar and chalk dust are both physically similar (fine white powders). However, they react differently with water; sugar dissolves in water and chalk does not. pH, a measure of acidity, is also a chemical property.

Some ingredients in toothpaste are necessary to clean and strengthen teeth while others are used for marketing strategies, for example "bubblegum" or "cool spearmint" taste. The ingredients of toothpaste made in this workshop are listed below with their specific functional use. Fluoride is only available to dental firms, and thus a substitute has to be used.

1. Sodium Bicarbonate (baking soda): this acts as a cleaning agent. This can neutralize the acids that cause cavities. This is also an abrasive to remove build-up on the teeth.
2. Calcium Phosphate: the Fluoride substitute. Fluoride is used in toothpaste to strengthen teeth. (If you have difficulty obtaining this ingredient, it could be left out, although Fluoride is an important ingredient in "real" toothpaste.)
3. Saccharin: the chemicals used in making toothpaste can be bitter, and need to be sweetened. Saccharin or Nutri-sweet can be used. (The best way to obtain Nutri-sweet is to use artificial sugar packets such as "Equal" or "Sweet 'n Low".) Sugar is not recommended for obvious reasons.
4. Washing soda (detergent powder): this is the cleaner that helps to get the food and plaque off of the teeth.
5. Glycerin: acts as a foaming agent, allowing a small amount of toothpaste to form a foam, and adequately cover the teeth. (Any liquid soap, such as "Sunlight" or "Palmolive" would also work.)
6. Water: is included to given a good "paste" consistency.
7. Peppermint extract: is used to give the toothpaste flavor. Other flavors can be used.

• 15 g sodium bicarbonate
• 11 g calcium phosphate
• 2 g Saccharin
• 3 g washing soda
• 1 ml glycerin
• water
• 1 drop peppermint extract
• 1 ceramic mold of a set of teeth
• 1 toothbrush
• 1 popsicle stick
• 4 50 ml beakers
• 1 400 ml beaker
• pH paper
• 1 tube Toothpaste (Crest™)
• 1L grape juice
• coke
• vinegar
• lemon juice
• paper towels

1. Place a small amount of the "Adventures Paste" on the paper towel. Place the same amount of Crest™ on the paper towel.
2. Dip one strip of pH paper into the "Adventures Paste" and another strip into the Crest™. Record the pH colour or number on the chart below.
3. Test the pH of the following common products as well and record the pH colour or number on the chart below.

Common Product	pH
"Adventures Paste"
Crest™ toothpaste
Water
Vinegar
Cola
Lemon juice

1. Rub a small amount of "Adventures Paste" between your fingers of one hand and a small amount of Crest™ between the fingers of your other hand. Determine which toothpaste feels "scratchier". Record your results.

The scratchier toothpaste is: ______________________________

1. Place some Crest™ on the toothbrush and brush half of the stained teeth for 2 minutes. Rinse the toothbrush off.
2. Place some of the "Adventures Paste" on the toothbrush and brush the other half of the stained teeth for 2 minutes.
3. Rinse the toothbrush and stained teeth in water and check which toothpaste cleaned the stained teeth better. Record your results.

"Adventures Paste"
Crest™
neither

The scratch test, Test #2, shows that "Adventures Paste" was slightly more abrasive than Crest™. Although mild abrasive properties are good for removing plaque build-up, this paste is likely to scratch away the enamel on teeth, like brushing your teeth with sandpaper.

The cleaning test, Test #3, is likely to show that "Adventures Paste" is a better cleaner than the Crest™. This is a result, at least in part, of the characteristics noted in the first two tests.

The testing process you followed in this project is similar to the one used to develop products for sale with the best properties for the customer.