Chantal Schmidt

Science, Grade 9

Mr. Harris

10/22/2015

Title: Investigating the effect of acids on Salivary Amylase

Introduction: Crackers (starch) are supposed to taste sweet in your mouth once you’ve been chewing them for a while . Salivary Amylase is there to help digest and swallow food. But what if your mouth is just too dry and you want to drink orange or lemon juice to help wash it down your throat? What happens, if you drink different acids, like orange, lemon or lime juice? Will it still taste sweet? Will it taste sour?

Research Question:  How does ­­­­­­­­­­­­­­a different pH level affect the productivity of your salivary amylase?

Hypothesis: If the pH becomes more acidic, the amount of sugar molecules increases slower.

Background information: Salivary Amylase helps digest your food. It converts starch molecules into sugar molecules. I am testing what effect acids have on the amylase. I used Orange juice and lemon juice and water, to compare acids to neutral fluids.

 

Identifying Variables:

                Independent Variable: pH

                Dependent Variable: Amount of time it took to taste sugar molecules after the starch came in                                                                   contact with amylase

                Controlled Variables: Amount of saliva

Amount of Acid (for example how much lemon juice you added)

Which Acids you use

 

 

Controlling Variables:

Independent Variable: Measure the pH levels of the acids on different litmus papers and wash                                                                             hands afterward to avoid acids getting mixed up. Also measure the same                                                                             amount of every different acid.

 

Dependent Variable: Cut the crackers (starch) into square pieces, with the same shape,                                                                                 so the different acids can equally show how they affect the salivary                                                        amylase on the crackers. Check how long the crackers have been in                                                          your mouth

                Controlled Variables: - Wash your mouth before and after every use and check the crackers have                                                                        been in your mouth, so each piece of cracker gets the same amount of                                                                 time and therefore get the same amount of saliva

• Put the acids in different testing tubes or glasses with the same shape, and fill them to a shared specific point, so you have the same amount of acids. Use different spoons with the same shape to transport these acids onto the starch or into your mouth

                                                               

Materials: Crackers (starch), Acids (Lemon, Orange), Saliva, Spoons, Litmus paper

Procedure: What steps did you take to perform the experiment and collect data?

Method steps (Note: “Gather materials” is not a step in your method)

Diagram (if applicable)

 (Measure the pH of the acids, if you already know it, leave this step out)

1. Put different acids into different testing tubes.

2. Cut crackers into squares/rectangles (all should have the same shape)

(Now start the experiment)

1. Put one cracker into your mouth (make sure to keep them apart to avoid mixing of acids)

2. Add a teaspoon of acid

3. Check the time

4. If you’re sure, that you taste sweetness, stop the time

Data:

                Qualitative data (observations table) - No numerical results in this section.

                Quantitative data (data Table) - Raw data

 

 

 

 

 

 

 

 

 

 

 

Analysis: I found out, that the higher the pH of your acid is, the longer it takes for the cracker to start tasting sweet

Graph: Title, X and Y axis labeled, graph is properly proportioned, and error bars are included.

 

Conclusion: My hypothesis was partly correct, since the higher the pH level of my acid was, the longer it took me to notice sweetness.

                 

Evaluation:

Table 3: Evaluation of strength and weaknesses

Possible Error/Weakness

Describe what could have affected your measured data.