Title: Comparing the pH of Household Products
Question: What is the pH reading of various household products (distilled
water, juice, Sprite, vinegar, seltzer water, hand sanitizer, baking soda,
and bubbles)and how do those pH readings compare with each other?
Purposes:
Scientific
1. Find the pH value of different household products using the red cabbage juice (indicator)
2. Use the indicator to identify acidic, basic, and neutral substances found in any home
3. Classify household items as acids and bases
Academic
4. Collect and analyze data
5. Organize and analyze results in tables and graphs
Hypothesis:
If we test the pH of several household products using cabbage indicator then I think the cleaners (vinegar, hand
sanitizer, baking soda, bubbles) will be more acid/base because ____________________________________ and the
foods (grape juice, sprite, seltzer water) will be more acid/base because __________________________________.
Variables, etc.
The indicator being used is ______________________________.
The independent variable is _____________ and the dependent variable is _____________.
Three examples of constants are ____________________, ____________________, and ___________________.
The control group is_______________ and the experimental group is ____________________.
Materials:
7 test tubes
Test tube rack
10 mL graduated cylinder
50 mL beaker
1.
2.
3.
4.
Experimental Test Solutions:
White grape juice
5. Hand sanitizer
Sprite
6. Baking soda
Vinegar
7. Bubbles
Seltzer water
Procedure:
1. Make predictions about which things will be acids, bases, or neutral.
3. Place a piece of white paper under the test tube rack, write the number of each substance to be tested (based on the
the way you numbered them on the data table) on the paper in front of each of the seven test tubes.
4. Record the colors of the products and the indicator in your data table (“Beginning color of product” and
“….indicator”)
5. Add one pipette full of red cabbage indicator to each test tube.
6. Add one pipette full of each household substance to each test tube.
7. Record the color change (final color), and color in your “data” test tubes.
8. Organize all test tubes from most acidic to most basic using the pH scale for red cabbage juice as a guide.
9. Estimate the pH value of each substance by using the pH scale for red cabbage juice
10. Classify each product as acid, base, or neutral.
11. CLEAN UP! Pour all substances into the sink followed by water. Rinse each used test tube. After removing the white
paper from below the test tube rack, set a clean paper towel below it. Set the rinsed test tubes upside-down in the test
tube rack.
12. Graph your results
INCLUDE THIS PAGE IN YOUR LAB WRITE-UP
DATA Table
Household
Product
pH of Common Household Products
Prediction
Predicted pH
Values (1-14)
Acid
Beginning color
of product
Acid (A),
Base (B),
Neut. (N)
Beginning
color of
indicator/
Grape juice
2.
Sprite
3.
Vinegar
4.
Seltzer
Water
5.
Hand
sanitizer
6.
Baking
soda
7.
Bubbles
8.
Control -Distilled
Water
INDICATOR + PRODUCT
Colored/labeled drawings:
Control
1.
Distilled water
2.
G.J.
Sprite
3.
Vinegar
Neutral
Product
+
cabbage
“cabbage
juice”
1.
Base
Final
color
4.
5.
Seltzer
6.
Sanitizer Baking S.
7.
Bubbles
Red Cabbage pH Scale
approximate pH:
color of extract
(cabbage + substance):
2
4
6
8
10
12
red
purple
(more red)
violet
(more blue)
blue
blue-green
Green
ANALYSIS
Graph your results from the most acidic to the most basic (bar graph) on a piece of provided graph
paper.
Conclusion paragraph Outline
1. The main idea (purpose) of this lab was …
2. It is important to learn about acids, bases, and the pH scale because …
3. When you added vinegar to red cabbage indicator, the indicator changed color from
_______________ to ___________.
4. Red cabbage juice changes from purple to other colors when……..This happens
because…..
5. The seven substances we tested from most acidic to most basic are…..
6. The examples of acidic substances were……. Examples of neutral substances
were……Examples of basic substances were…….
7. The data shows that most foods are mostly acid/base because …….
8. Cleaning supplies are mostly acid/base because...
9. Sources of error (mistakes) that may have occurred are 1……., 2………., or 3…………
10.A further test that could be done to experiment on the pH of foods and cleaning supplies
is………
Your Lab Report Should Include:
1. Title
2. Question
3.Hypothesis
4. Variables (indep., dep., exp. group, control group, constants)
5. Data Table filled in completely
6. Colored-in pictures of test tubes
7. Analysis Graph
8. Conclusion Paragraph