Acids & Bases

If you had a choice between a glass of lemon juice or apple juice, most folks would pick the sweeter one – apple. Did you know that apples are loaded with malic acid, and are actually considered to be acidic? It’s just that there is so much more sugar in an apple than a lemon that your taste buds can be fooled. Here’s a scientific way (which is much more reliable) to tell how acidic something is.


Acids are sour tasting (like a lemon), bases are bitter (like unsweetened cocoa powder). Substances in the middle are more neutral, like water. Scientists use the pH (power of hydrogen, or potential hydrogen) scale to measure how acidic or basic something is. Hydrochloric acid registers at a 1, sodium hydroxide (drain cleaner) is a 14. Water is about a 7. pH levels tell you how acidic or alkaline (basic) something is, like dirt. If your soil is too acidic, your plants won’t attract enough hydrogen, and too alkaline attracts too many hydrogen ions. The right balance is usually somewhere in the middle (called ‘pH neutral’). Some plants change color depending on the level of acidity in the soil – hydrangeas turn pink in acidic soil and blue in alkaline soil.


There are many different kinds of acids: citric acid (in a lemon), tartaric acid (in white wine), malic acid (in apples), acetic acid (in vinegar), and phosphoric acid (in cola drinks). The battery acid in your car is a particularly nasty acid called sulfuric acid that will eat through your skin and bones. Hydrochloric acid is found in your stomach to help digest food, and nitric acid is used to make dyes in fabrics as well as fertilizer compounds.


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Comments

32 Responses to “Acids & Bases”
  1. jma5447 says:

    cool

  2. Dabney Rigby says:

    man! i never new that would hapen 🙂

  3. Shiralee Seerden says:

    would it blow up if you mix it togetherl.

    Sam

  4. Martin Melody says:

    🙂

  5. Aurora says:

    You can test it with pH paper strips to see if you’re not sure. Pink and purple indicate an acidic soil, whereas blue will be a basic soil.

  6. Aurora says:

    The fizz is carbon dioxide gas. And you’ll want to try baking soda! You can also use chalk and vinegar, alka setlzer and water…

  7. Caroline Wood says:

    We have a hydrangea and it has both pink and purple flowers at the same time. Is the soil acidic or not, can it be both?

  8. Caroline Wood says:

    i was trying to make a fizz not using baking powder and i could not do it do u have any suggestions ? what is the fizz?
    Susanna

  9. Kacey Sauve says:

    Thanks I’ll try it today

  10. Aurora says:

    Well,the first thing I want to say is: “Try it!” 🙂

    For indicators, you want to use something that is sensitive to acids and bases, like beets (changes bases from red to purple), blackberries, blueberries (sometimes), carrots, curry powder, tumeric, grapes, and more! Here’s a BIG list: http://chemistry.about.com/cs/acidsandbases/a/aa060703a.htm

  11. Kacey Sauve says:

    I was wondering if you could use beet juice instead of cabbage juice.
    Thanks, Caleb

  12. Aurora says:

    If there’s no sediment, simply wash it down the sink. Tartaric acid can be washed down the sink with water, as the amounts of it are very small.

  13. Aurora says:

    It should happen right away. Try varying your measurements a little and try again?

  14. Marianne Chamberlain says:

    Another question. We have questions about how to dispose of things. Like the tartaric acid and any of the lime water,
    along with sediment, that we did not siphen out. The video talks about throwing away the sediment, but not extra water and it does not address the tartaric acid at all.

  15. Marianne Chamberlain says:

    I have a question about the calcium hydroxide experiment. How long do you need to wait for the particulate to fall out and get your lime water? We have waited over 30 minutes and some has fallen out and there is a thin layer of clear water on the top, but it is mostly still milky looking. It would be difficult even to try to pipet out some of the clear to test it as this point. Just wondering how this one is supposed to work.

  16. Aurora says:

    This is one of the most common concerns when substituting chemicals – what else is in there? That’s why chemistry supply houses spend lots of time removing trace elements. Look at the ingredients and see if there’s anything else listed besides calcium chloride. With pool additives you have to be especially careful, as other additives may not be listed on the label. When in doubt, skip it and find another source – the risk just isn’t worth it.

    Here’s a source that’s inexpensive: Calcium Chloride.

  17. Barb Milroy says:

    I was unable to find Dri Ez, but I found a pool additive by HTH called “calcium plus”. The label says it contains calcium chloride, but the warning label warns against mixing with any other chemicals. Is this the same product as Dri Ez – can I use this instead?

    Thank you!

  18. Aurora says:

    Wow…cool! I never thought to use spit (although I did try a sneeze once… in the lab in college, we used to sneeze on the test strips…)

  19. Lynn Woitalla says:

    We had fun with this experiment today! OxiClean is a good one to try. We also used our saliva to test the acidity in our mouths! (Ok, sounds gross, but we can be acidic or alkaline/basic too!!)

    We used the red cabbage instead of test strips and it worked great. We also tried the pulp portion, which works as well.

  20. Debra Thomson says:

    Cream of Tartar is a common powder used in cooking. You can find it in any spice isle at a grocery store.

    C.L.R. is a cleaning product used for dissolving calcium and lime deposits and rust stains, you can use it in the bathtub on metal, or whatever. C.L.R. is a specific brand, but I just found an old bottle of it, so I am not positive that it is still made.

    Bye, Sevy!
    -Steph

  21. sevy keble says:

    I don’t mean to go into other people’s conversations, but what is Cream of Tartar? And where can you get C.L.R?

  22. Aurora says:

    Cream of Tarter (Potassium bitartrate) is the leftover stuff when folks make wine. After evaporating the solids, bakers use the white powder (cream of tartar) to stabilize egg whites, keep sugar syrups from crystallizing, and keep the original colors of fruits and veggies after cooking. It’s also in baking powder as the acid needed to react with the baking soda. Tartaric acid is found in grapes and other fruits.

    Use baking powder if you need a quick substitute for cream of tartar and you should be fine.

  23. Debra Thomson says:

    I loved this. I even used an old bottle of C.L.R.(Calcium, Lime, Rust) and I got a BRIGHT pink with that!
    Thank you for all your amazing experiments, Aurora! This is the best science program I’ve done-I even REMEMBER the things I learn, usually a problem for me!
    -Stephanie, 13

  24. Debra Thomson says:

    Does Cream of Tartar work for the Tartaric Acid-or are they completely different?
    Do you know where we could find Tartaric Acid if Cream of Tartar doesn’t work?

  25. Aurora says:

    Ammonia is a STRONG base, used for cleaning, should be handled with great care. ALWAYS get adult help with this chemical, as the vapors are very strong (just breathing them gets them into your bloodstream, so do this experiment outdoors), and if mixed with bleach the two make a lethal gas that can kill you. So unless you’ve got a nearby grown up who’s helping you, skip this one. We’ve only provided the second video here as a demonstration so you don’t have to do this experiment yourself.

  26. Sevy Keble says:

    I already tried vinegar. What is ammonia?
    sevy keble 🙂

  27. sevy keble says:

    Wow, I had a lot of fun puting stuff on the home-made pH strips!
    sevy keble 🙂

  28. Aurora says:

    I had a question: we ordered the advanced chemistry kit, and it came, but it didn’t have that special blue paper that changes color. Why isn’t it there?
    sevy keble:)

    From Aurora:
    Hmmm… the litmus paper used to be a part of the set – they must have changed something. Here are a few options for you:

    1. Use the ‘universal indicator’ included int he kit. It’s a liquid form of the litmus paper, only with a wider range (meaning that it will change colors for both acids AND bases). Just add a drop to your solution, making sure that it’s a solution that doesn’t have a color that will interfere with your testing. (Coffee isn’t something you can test this way, as it’s too dark to see a color change.) Stick to clear and white things, like Sprite, baking soda, etc. You can also try Milk of Magnesia, ammonia and powdered Draino but make SURE you’ve got adult help with these chemicals!

    2. You can make your own pH strips by placing a few drops of universal indicator onto strips of paper towel or coffee filters and let dry. Now you can test coffee and orange soda.

    3. You can also buy pH strips at a local pharmacy or fish store if you really want to.

  29. Aurora says:

    No problem – it’s a good question!

  30. Stephen Chisholm says:

    oh, thanks, i mean, I was supposed to watch it for a homework assignment, and I didnt know if the video was glitched or something, I just wanted to make sure, and thanks again

  31. Aurora says:

    Yes, the video should look like that – mostly because it’s an excerpt from a 4 hour video. The next step covered something completely different so our video editor clipped it there, but should have put a tag at the end. Sorry for the confusion!

  32. Stephen Chisholm says:

    um, I think that you accidently cut this video short, I mean, at the end it sounds like someone hit the “stop” button on the camera

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