Spring is for Plants!

In my previous posts, I have mentioned using Building Foundations of Scientific Understanding for our elementary Science. We have been working through A thread (Nature of Matter) of BFSU Volume 1 all year. I had originally planned for us to start in Volume 2 and continue A thread (this is the Classical schedule coming through…), but over the past several weeks there has been a lack of interest in continuing with atoms and molecules. I think the beautiful weather outside has a lot to do with it! So I did some thinking and decided to reevaluate how we are doing our science. 

 
Bernard Nebel, the author of BFSU, encourages moving between the four “threads” or disciplines (Nature of Matter, Life Science, Earth and Space Science, and Physical Science). I’ve resisted this only because we’ve followed the classical schedule for the past several years, with one subject each year in a four year cycle. But as we move away from the classical schedule a bit, I find myself wanting to jump around a bit (though in an organized way so not stress out my Type A personality). 
 
With that being said, I decided to cover Plants this June. Everything is in bloom, the weather is nice, and we’ve got a great garden in our front yard to study as well.
 
Over the past week or so, we have been studying the basic structures of plants. The core of our lesson has been B10: Plant Science I – Basic Plant Structure. We started with the three basic parts of a plant – roots, stems, and leaves. We discussed how even vastly different plants all have these parts, though often in a modified form. She was fascinated to learn that the spines of a cactus are actually highly modified leaves. 

 

We have a membership with Notebookingpages.com, and I printed up several pages from the Plant Study collection. Over the past week, we have been working through these pages, identifying various plant parts, margin types, leaf arrangements, etc. The Visual Dictionary of Plants is a wonderful resource for learning plant parts.

 
Kyri and I went on a Plant Walk this week, armed with a few nature books and plant identification guides. As we explored, we discussed the three basic parts of a plant, and I asked her to identify various aspects of plants we found, such as:
 
type of leaves – simple or compound
arrangement of leaves – alternate, opposite, whorled, fascicled, or clustered
leaf venation – parallel, pinnate, palmate or arcuate
leaf margins – smooth, serrate, dentate, crenate, sinuate, lobed, or cleft
 
On our plant walk, she was particularly interested in finding a Sweet gum tree, because she had read about it and its identifying features in one of her books. We wrapped up our walk with the triumphant discovery of a Sweet Gum tree at the end of our street.
 
We have built up quite a collection of nature study books, and Kyri absolutely adores them. I can often find her with one or more tucked under her arm. Here are some of our favorites:

Here are several pictures from our walk!

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Dissolving, Solutions, and Crystallization

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We just wrapped up  A9: Dissolving, Solutions, and Crystallization. We started our week with some reading, to get an idea of what happens when various substances are put into water. We recently added Chemistry Pre-level I from Real Science-4-Kids as a reference book, and Chapter 6 (Mixtures) was a great introduction to what we covered this week. 

 
Part 1: Some things dissolve: Solutions and Mixtures
 
We covered a few basic concepts first. 
 
What is a mixture? When we combine difference substances, we have a mixture. We talked about a mixture of diffferent types of fruit in a bowl, and various toys in a box. Then, we talked about making a mixture by putting a solid into a liquid, like when we combine sugar and water.
 
For a demonstration, we made up a sugar solution as a demo. After stirring our sugar, we watched the granules slowly get smaller and finally disappear. Our solid dissolves, which means the substance, in this case sugar, comes apart into its basic particles and interact with the particles of water. This makes a special kind of mixture called a solution
 
We compared our sugar water mixture to a mixture of flour in water. After stirring a small amount of flour into a glass of water, we observed our mixture remain cloudy – our flour doesn’t come apart to interact with the water molecules as a solution but instead remains just a mixture.
 
Part 2: Soluble and Insoluble
 

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After comparing sugar-in-water and flour-in-water, we then explored a variety of materials to see what was soluble and insoluble. While we did some basic kitchen items, like vinegar and baking soda, we also found some fun objects like a matchbox car, a small block of wood, and a plastic toy. The kids enjoyed stirring these to see whether they would dissolve.
 
Why don’t certain objects dissolve? This was a great opportunity to review our earlier lesson on solids, liquids and gases, where we learned how objects’ particles are either very close together (in solids), interacting but not closely packed (as in liquids) or not in contact with each other (in gases). Our solid objects, with particles closely packed together, were not able to break apart and interact with the water particles. We prepared a chart to record our observations. 
 

A9 Soluble/Insoluble Chart download

Part 3: Crystallization
 

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We dissolved salt in water to observe not only the process of salt dissolving and forming a solution, but also of salt particles forming crystals. We recently learned about about evaporation, when the water molecules leave the liquid state and go into the gas state. Any solids that are dissolved in the water are left behind and reformed crystals
 
To help with our observation, we placed a couple of teaspoons of our salt solution on a dark plate, and left out to evaporate. We later observed a crusty film where our salt solution was before evaporating.
 
We also made a straw by twisting up a piece of paper and securing with tape. This straw was then placed in a jar of salt solution. Our liquid wicked up the paper straw and after the liquid evaporated, a salt crust (crystals) was observed on the surface of the straw.
 
This lesson helped reinforce our earlier lessons on the particle nature of matter, and the states of matter. Understanding this particle nature is essential for upcoming lessons on atomic and molecular motion.
 
 
 
 
 
 

Air is a Mixture of Gases

This year we have switched over to Building Foundations of Scientific Understanding. We are focusing on Chemistry topics, and so are working through primarily A thread in Volumes I and II.

This past week we’ve been working on topic A7,  Air: A mixture of gases (mixtures and chemical reactions).

Air is an excellent example for understanding molecules, mixtures and chemical reactions. Air is made up of nitrogen, oxygen and carbon dioxide. Oxygen is required by animals for respiration, and carbon dioxide is produced as a waste product. The oxygen and carbon dioxide in air are held constant in the atmosphere by green plants, which use carbon dioxide and emit oxygen. We’ve covered photosynthesis previously, in Biology as well as earlier this year when learning about energy, so this cycle is familiar around here. Here is a video that sums covers the Carbon Cycle.

We also love the app My Incredible Body  and learned all about respiration to get a better understanding of how we as animals breathe in air to bring oxygen into our body, and breathe out to expel carbon dioxide.

Air is made up of matter and has weight

Sometimes when we can’t see something, like air, it can be a little difficult to understand how it is made up of matter. To help visualize this, we set up this simple experiment. We started by tying string around the center of a wooden dowel, making sure the dowel was balanced. We then blew up two balloons, one much fuller than the other. We tied each balloon to an end of the dowel, spacing them the same.

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Kyri is a pretty smart cookie, so she expected the balloon that was inflated more to weigh more as well since it contained more air. As expected, the heavier balloon pulled its end of the dowel down lower!

Burning Requires Oxygen

We next set up a simple demonstration. Placing a tea light in a shallow plate of water (be sure to not cover the candle!), we then covered the candle with a jar and observed how, after just a short time, the flame sputtered and then was extinguished. I explained that the wax was the fuel (potential energy) and burning released this potential energy as kinetic energy in the form of heat and light. Oxygen is necessary for the fire to burn the fuel. Air is made up of approximately 20 percent oxygen, so in an enclosed jar, the oxygen is used up fairly quickly. Once the oxygen is used up, the flame goes out!

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Mixtures and Chemical Reactions

When we started discussing mixtures, we used some simple examples to understand – a mixture of coins or a bag of mixed candy. In those simple examples, the individual components didn’t change and were identifiable. But sometimes when components are mixed, a reaction occurs and the components are broken apart and new components formed. Our second demonstration involved the release of carbon dioxide during a chemical reaction.

Baking soda and vinegar can be mixed, and when they react carbon dioxide is released. This is a fun chemical reaction because of the intense fizzing!

Burning Releases Carbon Dioxide

Similarly, when a candle is burned (also a chemical reaction!), carbon dioxide is also released. Carbon dioxide, like air, is not visible. But we used a fun demonstration to produce and observe carbon dioxide.

We lit a tea candle in a shallow plate, and in a half-pint mason jar combined 1 Tbsp baking soda and 1/4 cup vinegar (Pour slowly to prevent fizzing over!). The carbon dioxide that is produced from the reaction remained in the jar and because it is heavier than air, can actually be “poured” like a liquid. We carefully tipped the jar toward the flame, as if we were pouring but taking care to not pour out any of the liquid contents. While we couldn’t see the carbon dioxide directly, we could observe the flame sputtering and finally going out, as the carbon dioxide poured over the wick and prevented the flame’s access to oxygen.

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