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Home School Life Journal
"Let us strive to make each moment beautiful."
Saint Francis DeSales
painting by Katie Bergenholtz

Chemical Reactions

One of the most fun parts of chemistry is looking at chemical reactions. In 2008, I gave the boys four substances: lemon juice, vinegar, baking soda mixed with water and milk. Their task was to systematically mix two of the ingredients and record the reactions.  They learned about precipitates (solids forming from a chemical reaction as two liquids mix), color changes and bubbles. They were particularly surprised when their cups bubbled over!


Now that they are a little older, I decided to try this experiment again. I picked six items for my students to test: baking soda, milk, vinegar, iodine solution, corn starch and red cabbage juice. I made the red cabbage juice by taking a red cabbage and after slicing it up into quarters and simmer it in a quart or two of water. Distilled water is best as the minerals in tap water can change the quality of the cabbage juice. You will need only a small amount for this experiment, but I knew I was going to do a series of acid/base experiments soon, so I made up a large batch of it. Once the cabbage has simmered for about 5 minutes, the juice can be drained off and put in the refrigerator until needed. The cabbage can be eaten.
Other items you could use include calcium chloride (which is salt you put on your steps to melt the ice), lemon juice, water, or egg whites. If you try other samples, be sure you know what the reactions will be so that you do not accidentally create a hazardous condition. For example, ammonia and bleach give off a noxious gas when they react together. I put my samples in disposable clear plastic cups and put a plastic spoon in each cup.


Since I still have some beginning readers and I did not want them to struggle with that aspect of the experiment, I color coded the cups of samples and I made up a sheet that made all the combinations possible. Now I was ready for my students.


They could look closely at each sample and they could smell them by wafting. In wafting a person takes an open hand with the palm towards the body and moves their arm in a rapid circular manner over the substance so as to lift vapors of the substance towards the nose. This method allows for a lower concentration of vapors to be inhaled and is particularly useful in safely smelling unpleasant or dangerous chemicals. Even though we were not using anything that was dangerous to smell, it is a good habit to get into for chemistry experiments. For this reason, I did not let my students taste any of the samples either, even though many of them could have tasted. After they examined the samples, we began the testing. I chose not to make a big deal about them spilling some of the samples on the table this time, but this is a good habit to teach them early, so I will work with them on how to handle materials without spilling them with future experiments. Part of the problem this time was that in the beginning we used hard plastic test tubes, washing them between uses, and these have very small openings. Later we used plastic disposable cups and we found they worked better than the test tubes because it had a larger opening and also they could see the reactions better. As each combination was tested, they noted how the chemicals had changed from their previous condition. We agreed on the result, and I noted it down. Through this experimenting they experienced most of the signs that chemical has reacted. They were able to see bubbles, color changes and precipitations. They did not experience the other indicator that a chemical reaction has taken place, which is a solution giving off or taking in heat. We will be doing experiments that have that component later.

Bubbles form when one of the molecules produced is a gas. Color changes occur, among other times, when an acid/base reaction occurs. Precipitations occur when one or more products of a reaction are no longer soluble in the solution.

These reactions are caused by the different ways the molecules react with each other. In combination reactions, two or more molecules combine to form a single product. We saw this in our previous experiment, when hydrogen and oxygen combined to form water. In a decomposition reaction, molecules break down to form other molecules. We saw this in the previous experiment when we broke water down into hydrogen and oxygen. A displacement reaction is when bonds are breaking and reforming all at once. In an exchange reaction, the atoms change places. These last two reactions are more difficult to show at home because they often cause volatile reactions.

9 comments:

  1. I just made a bunch of cabbage juice for indicator experiments, but I used tap water - we'll have to make another batch with distilled water, for comparison!

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  2. I still remember my first chemical kit, and I mixed everything I could think of together and was so disappointed when nothing exploded.

    I love the chart you made and their observations, so cool.

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  3. Thanks Phyllis for commenting on my blog. I added yours to my google reader, your chemistry study looks like such fun. So does your history, I checked out those history portfolio pages. I like them. I find them though over whelming. LOL. How are your kids liking them? That clay chess set is so so fun looking. Do the kids find the sheets too much? Are they frustrated by them? Or do they think this looks good. LOL.

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  4. The Portfolios for the older kids are blank and come with a Teacher's Guide with suggestions and illustrations you can add if you wish. Your students decide what they want to put in according to their interests. The Portfolios for the younger kids come with options for the very young without much writing and for the slightly older, with more writing. We add or not use things according to what my student and I agree on. We are using the Usborne's History of the World as our spine, and we just go through it a few pages at a time. I have them narrate and then we use that narration as a basis for what they will put in their portfolios. Since they are, in essence, creating their own history books, they take more ownership for them and their learning, so yes, they do like it. My 13-year old sometimes has problems sharing his interests because he is self-consious about it, but that is just a part of being a teen, I believe. My kids don't like to color much, so they have not been doing that very much. It would make them look better, but that is where they are right now. I don't see any benefit in pushing them on that right now. My 9-year old is severly dyslexic, so he struggles some with the writing. We take it slowly, and it is often not perfect. Sometimes we do the younger student's versions. I try to meet them where they are and encourage them to improve. I think these Portfolios make that easier. Hope that answers your questions, but if you have some more, please feel free to ask!

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  5. Fun, fun, fun! I like using cabbage juice indicator solution. I love the color coded charts, that was a fantastic idea, a great tool for early readers and/or visual learners!

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  6. May I ask...Is this lesson from the Real Science 4 Kids, Chemistry? I was glancing through your blog and it's an excellent source of information to help other homeschoolers. We did the Cabbage, with Baking Soda, Vinegar etc in a nature class we took and the kids LOVED it. Since then we have been on a mission to find more science things as much fun as this!

    I did a search for the Friendly Chemistry that you have listed under your Curriculum but not sure that I found the right one...May I ask who the Author was for this. Do you mostly use Real Science 4 Kids, Chemistry? We are searching for a hands-on type of science program and would love any advice we can find. I am now looking forward to spending time reviewing and learning from all these great posts you have shared! Thanks so much!!! April

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  7. The color stickers were an awesome idea for your young scientists!

    Can i comment on your earlier two posts as well? I love the clothespin knights! Tell Katie she did a great job on those AND on the chess pieces. Did she make the chess pieces out of sculpty?

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  8. April-Yes, this is mostly from Real-Science-4-Kids, however I have been doing this for so long,that I add a bit from here and bit from there. It is a lot like making soup. When you first make it, you follow a recipe, but as you get more confident, you might take out a thing or two that doesn't suit your family's tastes or add in a few things to see how that works. I have done the same thing with our Chemistry program. Each RS4K book only lasts for 10 weeks. I would start with the Pre-level and then go on to Level I, but I must tell you that there is virtually no difference between the experiments for Pre-Level and the ones for Level I. That is it's weakness.
    Friendly Chemistry is by Joey and Lisa Hajda, but it is for Middle to High Schoolers. I have an 8th grader I am using that with.
    Mrs Random- Yes, the chess pieces are made from Sculpy, and thank you; I will pass on your kind words to Katie. It will make her day.

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  9. Phyllis,
    I get what you are saying! I do the same thing once I have figured it out. Thank you so much!!! I can not wait to try this science out. I requested several different science experiment books from my local library last night that I am hoping to add in:)

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Thank you so much for taking the time to comment. It means so much.