Make sure everyone understands the answers. Consider testing items found in the kitchen, bathroom, laundry and garden. Once students have completed the worksheet, have them manipulate this equation to solve for the concentration. Have students use this equation for each liquid's pH value to determine the concentration of hydrogen ion in each of the seven liquids.
Helmenstine, Anne Marie. However, these contents do not necessarily represent the policies of the NSF, and you should not assume endorsement by the federal government. Why Teach Engineering in K? Find more at TeachEngineering. Introduction to Water Chemistry. Quick Look. Print this activity. Suggest an edit. Discuss this activity. Curriculum in this Unit Units serve as guides to a particular content or subject area. TE Newsletter. Subscribe to TE Newsletter. Summary Students take advantage of the natural ability of red cabbage juice to perform as a pH indicator to test the pH of seven common household liquids.
Then they evaluate the accuracy of the red cabbage indicator, by testing the pH of the liquids using an engineer-designed tool, pH indicator strips. Like environmental engineers working on water remediation or water treatment projects, understanding the chemical properties including pH of contaminants is important for safeguarding the health of environmental water sources and systems. Analyze and interpret data to determine similarities and differences in findings.
Grades 6 - 8 More Details View aligned curriculum Do you agree with this alignment? Knowledge gained from other fields of study has a direct effect on the development of technological products and systems.
Missouri - Science Science understanding is developed through the use of science process skills, scientific knowledge, scientific investigation, reasoning, and critical think Grades 6 - 8 More Details View aligned curriculum Do you agree with this alignment?
Red Cabbage Chemistry Worksheet pdf. This water-soluble pigment is also found in apple skins, plums, poppies, cornflowers, and grapes. Very acidic solutions will turn anthocyanin into a red color. Neutral solutions result in a purplish color. Basic solutions appear in greenish-yellow. Therefore, you can determine the pH of a solution based on the color that it turns the anthocyanin pigments in red cabbage juice. Acids will donate hydrogen ions in an aqueous solution and have a low pH pH 7.
Chemicals used in this demo may be safely washed down the drain with water. You can conduct a neutralization experiment using a cabbage juice indicator. First, add an acidic solution such as vinegar or lemon, then juice until a reddish color is obtained. Add baking soda or antacids to return the pH to a neutral 7. You can make your own pH paper strips using a red cabbage indicator. Take filter paper or coffee filter and soak it in a concentrated red cabbage juice solution.
After a few hours, remove the paper and allow it to dry hang it by a clothespin or string. Cut the filter into strips and use them to test the pH of various solutions. To test a sample, place a drop of liquid on the test strip. Don't dip the strip in the liquid because you'll get cabbage juice in it.
An example of a basic solution is laundry soap. This is a great way to introduce the concept of acids and bases to a child since they can see the color change before their very eyes. We used these same scientific principles to create an amazing fizzy color changing chemical reaction and to dye Easter eggs naturally , which were both so much fun. I cannot wait to start using these with my 5 year old!
Should I do it again? Hi Elizabeth, I would just use the dark blue cabbage water and see what happens when you drop into acidic or basic solutions. It could be very interesting! There are a variety of reasons that your red cabbage water came out dark blue instead of purple. There may have been some kind of residue in your saucepan or there might be minerals in your water that make it slightly alkaline.
The red cabbage you purchased may have been grown in more alkaline soil, too. Feel free to try it again with a different head of cabbage or using bottled water instead of tap water and see if it comes out purple.
And let me know what you find out from your experimentation! I have always used tap water, but I can certainly see the benefit of using distilled water to prevent contamination.
Great question, thanks for asking. Thanks for this! I have small classes so a little cabbage goes a LONG way. I was just wondering if it would be ok to freeze it, and I came across this post.
This is great! What are the other alternatives I can use? Red cabbage is available at the grocery store though! Would it work if I use the red cabbage indicator as a liquid instead of freezing them, or is freezing mandatory.
So cool! What is the advantage of using ice cubes instead of the liquid? Search for:. Previous Next. Pin 5K. Share
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