Edible Science {Incr-Edible Science}

Having four young girls and at least two of them being passionate about being in the kitchen, I thought I would take a bit of time and create a curriculum that not only teaches my children how to cook but also teaches them why ingredients work as they do.  The science of cooking, if you like, otherwise known as edible science.  I hope this will enable them to be proficient in the kitchen, able to substitute ingredients intelligently and also to have the joy of  understanding how to create their own recipes.  My son will also enjoy it because anything scientific floats his boat!

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Read More! In addition to these homemade Edible Science Lessons, I have also begun a homeschool One Year Pond Study

Incr-Edible Science: The Science of Bicarb

This kitchen science is now affectionately known by all in the house as ‘Incr-Edible Science’

We will start with the science of Bicarbonate of Soda. This week the little ones will be experimenting with bicarb and colours so there’s a nice over-lap.

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Atomic Theory

We started with a lesson about atoms and molecules from the Atomic Theory book above.  I read the atoms and molecules chapter. After which, we started building some atoms first and then molecules. 

Building Atoms

I tried to focus on atoms and molecules I knew we would use in our Incr-Edible science.  The marshmallows were the electrons and the coloured jelly sweets represented different nuclei.  The toothpicks were there simply to hold everything together:

Building Molecules

Let’s see what happens when an oxygen atom joins two hydrogen atoms to make water:

This was simple enough, and the understood fairly quickly.

Building Sodium Bicarbonate

Then they tried to build a Sodium Bicarbonate compound.  First I wrote its chemical equation on the board and asked them to tell me the atoms in each compound and the proportions:

They seemed to understand this no problem.  I asked them to build each atom. And then try to work out how they react together to form the Sodium Bicarbonate compound. The Macauley book explained this well.  First, they built the sodium atom (atomic number=11) and then worked out correctly how the Bicarbonate was formed:

Next, they noticed that the Sodium, if it shared its electron, still wouldn’t have a full outer shell it needed for stability.  They knew then it needed to give its electron to the Bicarbonate, thus ensuring all outer shells were complete:

Atoms, Molecules…and Ions

I asked the children what the Sodium atom was now called.  They struggled to understand what I was asking.  So, I got them to count the protons in the Sodium (atomic number=11 so there were 11 protons). Next, I had them count how many electrons (given one to the Bicarbonate  so was left with 10).  I then asked how this would affect the charge of Sodium. For example, was it more positive or negative, and by how much.  They understood and replied that it now had a positive charge of one.  L10, who understood everything really well, remembered that an atom with a charge was called an ion:

Next, I asked what charge the Bicarbonate would have.  They counted and found it had a negative charge of one having gained an extra electron from the Sodium:

Solubility in Edible Science

I asked them to think about whether the Sodium ions and Bicarbonate ions would be close together or far apart.  They all agreed close together as each ion had an opposite charge and would therefore be attracted to each other.  Sodium bicarbonate is a chemical compound more commonly known as baking soda.  It is a white, crystalline salt which is soluble in water.  They checked its solubility:

They found it dissolved:

They asked for a clue…

So, I asked what was happening to the ions.  T11 remembered that in water they separated and reacted with the water.  I asked them to concentrate on the bonds. For example, which might be broken, which might stay the same and which might be formed.  I taught them that the Sodium Bicarbonate would separate into Na ions and HCO3 ions and the HCO3 ions would abstract a proton from water.  This will form carbonic acid (H2CO3) which naturally decomposes to form CO2 gas and water:

NaHCO3 + HOH —>  Na^+1 (aq) +  OH^-1 (aq)  + H2CO3 (aq)

H2CO3 (aq) —>  CO2 (g)  +  H2O (l)

NaHCO3 + HOH —>  Na^+1 (aq) +  OH^-1 (aq)  +  CO2 (g)  +  H2O (l)

I left this preliminary lesson at that and told them they could eat our chemistry lesson!

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Next time I planned to go into acidity and alkalinity, potential Hydrogens and hence the reaction in the kitchen between the alkaline Sodium Bicarb with an acid such as lemon (to produce lemonade), buttermilk (in bread to produce the leavening for soda bread) and glucose syrup (to produce the holes in honeycomb)  We would then get down to the real fun of making all these and carrying out a little of our own experimental tampering with all the recipes to see how changes might affect the outcome.  Lots of fun ahead!