Sugar is one of the most common ingredients we have in the kitchen. We use it for cooking, coffee, and making chocolate, cake and cookies. It is easy to obtain and safe, so it is a great subject for young kids and microscope enthusiasts to start their exploration.
Compound microscope and stereo microscope are both great tools to use. However, the sugar crystal is a 3-dimensional structure, so a stereo microscope offers a better result, allowing you to see the 3D structure and its texture. In this post, I will use a digital stereo microscope for demonstration.
What is Sugar? What is sugar made out of?
The white stuff we called sugar is sucrose. The chemical formula of sugar is C12H22O11, which means each molecule contains 12 carbon atoms, 22 hydrogen atoms, and 11 oxygen atoms. Sugar is a carbohydrate by looking at its chemical formula (containing carbon, hydrogen, and oxygen). However, the chemical formula usually does not give me a sense of its structure and what is made of.
Structurally, sucrose is two simple sugars (monosaccharide) linked together: glucose and fructose. Sugar is mostly found and extracted from sugarcane and sugar beets.
[In this image] Sucrose is a disaccharide that is made up of two monosaccharides: glucose and fructose. The glucose and fructose are connected by a glycosidic linkage.
How to observe sugar under a microscope
The material you need
- Blank microscope slides and coverslips
- Forceps
- A variety of sugar, I use “Domino sugar” and “Sugar in the raw”.
- Compound microscope/ stereo microscope/ digital microscope
Steps
1. Put several grains of sugar on a microscope slide. If you use a compound microscope, put a coverslip on it (prevent it from scratching the objective lens). If you use a dissecting microscope or a digital microscope, you don’t have to put a coverslip. There is lots of space between the objective lens and your specimen.
2. Start with a lower magnification. Move the focus knob carefully for sugar crystals to come into clear focus.
3. Look at the shape, color, size, and texture of the sugar crystals, then shift to the high-power objective lens. See if you can see some details.
4. If your microscope has an Interpupillary Adjustment, you can adjust it for simultaneous binocular vision. This allows you to see the crystal in 3-dimension, which is one of the advantages that is over the compound microscope.
Sugar under a microscope
I am using a digital microscope as an example. When a specimen, such as sugar, is light in its color and transparent, you could place a piece of black paper below a microscope slide. A darker background makes clear crystal stands out and easy to observe their details.
Sugar in the raw
[In this image] Sugar in the raw under a digital microscope.
The scale bar represents 1 mm. Notice how large these sugar crystals are. Their golden color comes from the natural molasses from sugar canes.
Domino sugar
[In this image] Domino sugar under a digital microscope.
The scale bar represents 1 mm. Notice these sugar crystals are much smaller than the “sugar in the raw”. Both images are taken with the same magnification.
Sugar crystals appear cuboid and come in different sizes. They look a bit more transparent than they appear on the view with your naked eyes. You can see sugar crystal has a fairly flat surface with sharp corners. Some corners are rounded off quite a bit because they bump into each other causing erosion of the edge.
The “raw in the sugar” appears to golden color because they contain natural molasses from sugar cane. The dominos sugar is the dietary sugar we use for coffee and tea every day. Their crystals are much smaller and appear white transparent.
Artificial sweeteners
While I looked at these sugar crystals under my microscope, I was wondering what artificial sweeteners and sugar substitutes look like. Do they look the same with sugar crystals? so let’s take a look!
Splenda
Splenda is made out of sucralose, which is a zero-calorie artificial sweetener. Sucralose is made from sugar. A chemical process tweaks its chemical structure: three hydrogen-oxygen groups are replaced with chlorine atoms. This chemical tweak makes it 600 times sweeter than sugar.
[In this image] Sucralose chemical structure.
Sucralose is made from sucrose. Three hydrogen-oxygen groups are replaced with chlorine atoms, indicated by red arrows.
[In this image] Splenda under a digital microscope.
The scale bar represents 1 mm. Unlike the sugar crystal, Splenda doesn’t have crystals. Splenda appears as chunks of white powders.
Equal sweetener
Equal sweetener contains dextrose with maltodextrin, aspartame, and acesulfame potassium.
[In this image] Equal sweetener under a digital microscope.
Equal sweetener looks very similar to Splenda under a microscope, although their chemical composition is different. The scale bar represents 1 mm.
Sweet’n low
Sweet’n low is made primarily from saccharin. It also contains dextrose, cream of tartar, and calcium silicate (an anti-caking agent).
[In this image] Sweet’n low under a digital microscope.
Sweet’n low has some pillar crystals structure under a microscope. The size of the crystal can be big or small. The scale bar represents 1 mm. You can compare the size of Sweet’n low and the regular Domino sugar in both images because their magnification is the same.
Now it’s your turn. Ready for exploring the sugar under the microscope?