Chemistry is arguably the most practical of all the science subjects. Learning the discipline teaches you a lot of skills that can be put to good use in everyday life, but especially when you need them most – when the SHTF.
I am an ex-chemist. I did my first degree in applied chemistry and worked as a chemist in environmental analysis and then pharmaceutical analysis before teaching chemistry. Although I don’t work as a chemist now, I have never lost my love of the subject. Chemists are often people who like to get their hands dirty. We love to experiment and make things. This is the core of the science and one which I hope to share some of the secrets of here, so you can use them, yourself, if you ever need to. I’ll also throw a little bit of chemistry into the mix too – if you’re anything like me, you’ll like to know the ins and outs of how, what you’re doing, works. So don your white coats and safety glasses and let’s enter the prepper lab!
Experiment 1: How to test if something is an acid or an alkaline
Acidity or alkalinity (basicity) is also known as the pH of a solution. The H in pH represents a hydrogen ion, as in the element hydrogen with a positive charge represented by the +. Hydrogen naturally holds a positive in its ionic charge so is often written as H+. If there are a lot of H+ ions hanging around in a solution it will show up as being more acidic when tested. Fewer of these ions will show up as more basic. If you have a balance between the H+ and the OH– of the water (H2O) then you’ll have a neutral solution. pH is measured using a scale of 1-14: 7 is neutral, below 7 acidic (the lower the more acidic) and above 7 is basic (the higher the number the more basic).
pH and Soil
It’s often important to know the pH of soil. Certain plants grown better in more acidic soil than alkaline and vice versa. Cops like blackberries and potatoes like a slightly acidic soil (around pH 5) and crops like shallots and pumpkins prefer a more neutral soil pH (around pH 7). A full range guide on vegetable plants and pH preferences can be found here.
It’s worth keeping a hard copy of it.
Making your homemade pH test kit
This is based on red cabbage. Red cabbage contains a pigment called anthocyanin, which gives the cabbage its red color. To make a test for pH we need to extract the anthocyanin from the cabbage. You do this by chopping up cabbage and pouring boiling water over to just cover the chopped cabbage. You then leave it to steep until the water turns a red/purple color (this is a solution of anthocyanin).
After about 15 minutes, filter the liquid mix to remove the cabbage, leaving the anthocyanin solution. You can then use this to test your soil.
To test the pH of soil you need to:
- Take some of your anthocyanin solution in a small glass
- Add about a teaspoon or two to the solution
- Shake the mix and wait for the color to form (may take up to 30 minutes)
- Check out the color against the chart below and you can then tell the pH of your soil
The pH range you detect and colors are:
Color Red Purple Violet Blue Green Green/yellow
pH 2 4 6 8 10 12
Adjusting the pH of your soil
If the pH of your soil isn’t good for the plant you want to grow, you can adjust it by digging in lime or sulfur to adjust the pH value. This article shows how much of each you need to add to get an adjustment in pH.
Experiment 2: Saponification or making soap
I remember coming across the term saponification as a child and thinking how similar it was to the word soap, and then finding out that it was, in fact, the way you make soap. It was one of those revelation moments that we all have, silly, but nice when they happen.
Making soap is something that has been performed by human beings for thousands of years, the first evidence for soap making being from ancient Babylonia around 2800BC. Soap is important stuff. It keeps you clean, so that the likelihood of infection is reduced, in a word without antibiotics and modern medicine, this could be a lifesaver, so it really is worth learning how to do it. You can also make soap that contains natural anti-septic, making it even more useful for medicinal purposes.
Soap is made from a chemical reaction between a chemical called a ‘triglyceride’ and example being oil such as olive and an alkaline, such as potassium or sodium hydroxide. Saponification happens when the alkaline causes the oil to break chemical bonds in the oil molecule. This then forms glycerol and ‘soap’.
Making a simple soap
- 1 pint Oil – you can use a variety, such as coconut and olive – the purer the better
- 3 oz. Lye (which is actually sodium hydroxide) you get instructions on how to make it here.
- 1/3 pint water
- Optional ingredients such as perfumed oil, herbs, tea-tree (antiseptic), etc.
- Slowly add the lye to the water. Do lye into water, NOT water into lye otherwise it’ll splash and you don’t want alkaline solution in your eye, believe me. It’ll warm up, so leave to cool.
- Add the oil to your lye solution. Slowly mix.
- Mix more vigorously, being careful not to splash yourself.
- Once the solution becomes thicker, this is called the ‘Trace’.
- If you’re using any perfumed oil or herbs, etc. add them now.
- Pour the thick ‘soap’ into moulds (ideally flexible plastic ones)
- Leave to set and in about 24 hours it should be ready to remove from the mould.
- Leave to fully set for about another month (turning every few days) and its ready to use.
Experiment 3: Lowering the freezing point
We all know that water (H2O) freezes at 0C or 32F. But did you know that you could change this so that water freezes at a lower temperature? In chemistry it is called ‘freezing point depression’ and you can do it to all sorts of solutions, including water. What happens is this. When water goes from a liquid to a solid (ice) it goes through a ‘phase transition’. The molecules in the liquid water effectively slow down because the amount of energy available (i.e. the temperature of the air) is reduced. Water molecules are a bent shape, like two splayed legs, and they are oppositely charged, so attract each other. If the molecules start to slow down, because it is colder, the molecules start to line up together and the opposite charges of the H+ (hydrogen) and O– (oxygen) form weak bonds. This eventually forms the solid, ice.
If you add certain other molecules to water, for example, salt, which is also made up of charged atoms, Na+ (sodium) and Cl– (chlorine) then these charged atoms get in the way of the H and O atoms and disrupt ice formation. Alcohol (which has an OH– group) has a similar effect on water; most anti-freezes have alcohol as an ingredient.
Typical uses of melting point depression
The most obvious use and one you’ve no doubt used yourself, is to stop ice forming on roads, to prevent slippery surfaces forming. The trouble with this is that if it is near plants or water, the salt can contaminate.
Perhaps a more fun use of melting point depression is to make ice-cream. If you surround an ice cream mix in a metal pot with ice, then add salt to the ice, the temperature of the ice decreases and draws out heat for the metal containing the ice-cream mix, causes it to freeze faster.
Experiment 4: Making methane gas (coal gas)
Methane gas, which is a very simple molecule made up of one carbon with four hydrogen atoms attached, CH4 can be made from heating coal using a process known as ‘destructive distillation’.
The process involves heating coal in a tube and collecting the resultant gasses in another tube, after bubbling through water. I first did this experiment when I was around 12 years of age. I made the mistake of taking the heat away too quickly and the contaminated water in the collection tube bubbled back up through the tubing in the heating tube, making a big mess –lesson learned, don’t pull the heat away from the coal until you’ve collected your gas and then do it slowly.
When you heat coal up, it decomposes to release a gaseous mixture. This mixture contains, methane (CH4), carbon monoxide (CO), hydrogen (H2) and carbon dioxide (CO2). When you go through the process of heating up coal in this experiment, you also get the by-products of coke, coal tar and ammonium hydroxide.
What you’ll need to make methane gas
- Some ground up coal
- Two vessels, heat proof glass, or metal. The first will hold the coal, the second will hold water
- Something to cover the vessels to make them air tight (e.g. clay or stopper with holes for tubing)
- Heat source
- Gas collection method, this could be a balloon or something similar, like a plastic bag that can be filled then closed tight.
You need to rig up your kit so it looks like this setup below:
- Heat the coal up, from underneath the container, using a heat source.
- This will eventually start to produce gas. The gas flows along the vessel and enters the tubing where it flows and bubbles through the water (the tubing needs to go under the water).
- Ammonia in the gas dissolves in the water to form ammonium hydroxide (NH4OH) and sediment of coal tar is deposited under the water.
- The rest of the gas bubbles out through the water and passes out of the vessel through the open tube into the collection point (e.g. a balloon or similar).
- Coke is left in the heating vessel.
- You can make use of all of the products of this experiment.
Making use of coal gas
The first commercial use of gas lighting was by the London Gas Light and Coke Company was established in the UK in 1812. This company supplied coal gas to use to light up various ‘modern’ establishments including the houses of parliament. Gas lighting was still used in homes in the USA until the early pat of the twentieth century. We can use coal gas for lighting today too, if we don’t have electricity supply anymore.
It might be tricky to make a lamp out of coal gas without the use of a ceramic burner made especially for the purpose, but coal gas can be used for other purposes.
Coal gas is a good fuel. You can make a coal gas burner by using a small aperture tube and releasing the gas through this tube and burning it off as it comes out. You can also run petrol engines on coal gas too; in fact soldiers used this in WW1 when they ran out of petrol.
If you get the chance, check out “American Mechanics’ Magazine: Containing Useful Original Matter Volume 1” from 1825 as it has some interesting discussions on making and using coal gas.
Experiment 5: Using urine to make potassium nitrate (for gunpowder)
Urine is great stuff; it’s a waste product that shouldn’t be wasted. Although urine is mainly water (95%) it also contains important chemicals that can be used to make gunpowder and fertilizer. The rest of the chemicals in urine are:
- Urea (which is a nitrogen based organic compound)
- Various small amounts of ions and trace elements
In this experiment, it is potassium we’re focusing on, but many of the other constituents, even the water, can be made use of.
This experiment shows you how to make potassium nitrate or KNO3 The K is the chemical symbol for potassium, N for nitrogen and O for oxygen. So you can see potassium nitrate s a mix of these three elements.
Making the potassium nitrate
Potassium nitrate is one of the main ingredients in gunpowder, so when the SHTF knowing how to make this, may well come in useful. The other ingredients in gunpowder are sulfur and charcoal.
Making potassium nitrate the tradition way involves a lot of manure (to supply bacteria), lots of urine (to supply the potassium) and about 10 months for it to percolate.
How to make your potassium nitrate:
- Collect some manure in large container (needs some way of drawing off liquid like a tap or blocked hole)
- Add wood ash to the manure
- Mix in some straw (this helps to aerate it)
- Add urine, lots of it, over time to the wood ash mix
- Stir every so often
- Near the end of the process (about 10 months) add a good amount of water and drain off, collecting the liquor
Step 1: Solution of potassium nitrate
Urea and any metabolized ammonia are oxidized by the bacteria in the manure to nitrate which react with potassium carbonate (in the wood ash). This forms a mix of soluble potassium nitrate and insoluble calcium and magnesium carbonates. The soluble potassium nitrate can then be drawn off from the mix in the liquid.
Step 2: Crystallizing potassium nitrate
To make the solid form of potassium nitrate used in gunpowder you need to crystallize the potassium nitrate out of the solution. To do this:
- Boil up the liquor you’ve drawn off from the mix with charcoal. This removes the color
- Filter off the charcoal through a cloth
- Now reduce down the liquid by gently boiling. You’ll see the liquid reduce in volume.
- Start to cool it when you have reduced the volume by about ¾.
- Using (ideally) a glass rod or long piece of glass, dip it into the solution, pull out and as it cools if you see white crystals forming you know it’s now a saturated solution
- Cool this down as much as possible (surround the container with ice if you have it)
- Filter your saturated solution through a fine cloth, like gauze (or filter paper if you can get some).
- The crystals then need to dry out on the cloth or paper
TIP: When you are forming crystals you can ‘start them off’ by seeding the solution with the crystals on your rod (step 5) and / or scratching the sides of the container with a glass rod. This creates a surface for the crystals to stick to. Once one crystal forms, the rest quickly form around it. One of the most amazing things I’ve ever seen, is the sudden formation of masses of crystals in a saturated solution after scratching the sides of the container, it’s like magic.
NOTE: Saltpetre is the old name for potassium nitrate.
There’s a good text from 1862 on the manufacture of Saltpetre here.
How to make the Gunpowder
Gunpowder is a mix of 75% potassium nitrate, 15% charcoal and 10% sulfur.
You need to grind each of the components into a fine powder.
IMPORTANT: Grind each one separately! If you grind them together you might end up testing out your gunpowder on yourself.
Once ground up, they need to be very finely mixed together. This is an important part. Ideally you need to put the mix into a tumbler to get the parts well mixed. If you don’t have a tumbler, then just take some time and mix very well (remember – don’t grind at this point).
Once its mixed this is known as ‘meal powder’. The ideal form of gunpowder is in the form of grains; the size of the grain determining the speed at which it burns, the smaller the better. To get small grains you can mix the power with water to form a paste and then press the paste through a fine-grained sieve. You should then (ideally) tumble the grains to make them smooth.
IMPORTANT: If you tumble the meal powder, DO NOT tumble with certain metals like steel and iron (in fact anything that can create a spark, which include many plastics), wood would be OK to use.
Like all good alchemists, you must always take precautions when using certain chemicals. For example, alkaline solutions, such as lye, are very corrosive and as someone who has had concentrated sodium hydroxide on her hands before, take it from me, it hurts! So be careful.
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Image credits: Zu Sanchez