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| Supplies (my vinegar is in a spray bottle, as I use it for cleaning) |
Here is a fun and easy lab to learn about acids and bases. Most of the ingredients are probably already in your galley / kitchen. I've modified it a little for homeschool use.
Materials:
white paper
scissors
pencils, crayons, colored pencils
*science journal (optional)
1 Red cabbage for indicator solution (Boil the head of red cabbage in water for approximately 10 minutes, let the liquid sit until cool. Pour into a large pitcher. This can be made ahead of time and stored for one week in the fridge).
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| Boiling cabbage to make the indicator solution. |
a few clear containers (whatever you have on hand, such as tupperware, glasses, etc).
•pH scale chart (print out one you like online, laminated, or placed inside a clear plastic bag)
•pH paper strips (see list of resources for making your own pH paper strips down below) *optional
Substances to test:
lemon juice (can also test lime, orange, or other citrus fruits)
baking soda
white vinegar
marina water or the water in the anchorage
your boat's water-maker water
dish soap
clear soda (can also be soda water)
(feel free to add to this--ask the kids, they always come up with different things to test, such as toothpaste, shampoo, laundry detergent, etc).
Vocabulary: acid, base, neutralize, precipitate, pH, scale, substance, indicator
Asking Questions: What do you know about acids and bases?
Plan and carry out the investigation: what materials will you need to conduct this lab? What other materials would you add or substitute?
Conduct the experiment:
1. Using a clean sheet of white paper, draw the number of sections correlating to the number of substances you will be testing. See example.
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| My daughter's example testing mat |
2. Take a clear container and add a small amount of the indicator substance (cabbage juice). Draw a picture of the control (cabbage juice before you add a substance to it). Note the color.
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| Indicator solution. |
3. Next, add the first substance you are going to test. Record any changes to the indicator. Use the pH paper and dip it into the substance. Compare the pH paper to the pH chart and record the number. Set the used testing strip next to the label on your sheet of paper.
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| This was the color after adding the first substance we were testing (in this case, lemon juice). |
Substance tested:_________ Color when added to the indicator:___________ pH level:__________ Observations/Illustrations:
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| Second substance we tested (in this case, baking soda) |
Substance tested:_________ Color when added to the indicator:___________ pH level:__________ Observations/Illustrations:
5. Repeat the above for the remaining substances you are going to test.
Analyze data, interpret observations:
What happened to the indicator when an acid was added?
What happened to the indicator when a base was added?
What happened to the indicator when tap water was added?
Questions, planning further investigations, creating a model:
How can you apply the knowledge gained from this investigation to our planet? For example, think about your local watershed and how pollution may be impacting it. Write your thoughts here:
Focus questions:
1. If the pH of the ocean becomes more acidic or basic, what might happen to the flora (plant life) and fauna (animals)?
2. Why would a higher or lower pH level in a local river indicate a problem with the watershed?
Resources: Here are some extra resources to help make this lab successful (without spending a lot of money).
1. Making your own pH paper (you can do this ahead of time or along with your kids as a separate activity!
Here is how I did it on the boat:
1. Cut the white paper into strips as shown.
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| Preparing the strips. |
2. After making the indicator solution, pour some into a bowl and toss in the strips. Make sure they soak at least 20 minutes. Take out and set on a paper towel to dry overnight. They will be ready to use the next day.
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| Soaking the strips in indicator solution. |
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| Setting them out to dry. The color will lighten up a bit. |
A couple of other resources I found:
http://chemistry.about.com/od/chemistryhowtoguide/ht/makephpaper.htm
http://www.wikihow.com/Make-Homemade-pH-Paper-Test-Strips
Litmus paper: Mostly made from wood cellulose. Easier to purchase than to make. *You don’t have to use litmus paper for this activity. You can use pH paper with great results.
2. Brain Pop video and lesson activities about the pH scale:
http://www.brainpop.com/science/matterandchemistry/phscale/preview.weml
3. Chem4Kids.com : http://www.chem4kids.com/files/react_acidbase.html 4. Chemistryforkids.net: http://www.chemistryforkids.net/help/ph-scale
4. Environmental Protection Agency extensions
http://www.epa.gov/acidrain/measure/ph.html
http://www.epa.gov/acidrain/education/site_students/index.html
Copyright © 2018 Stefanie Pechan All rights reserved by author.
For the full write up of the lesson plan photos, and student worksheet packet: http://www.teacherspayteachers.com/Store/Mrspechan
No commercial use without written consent from the author: contact@mrspechan.com
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