How much sugar is in your drink?

Sweet drinks are popular, even if they contain a lot of sugar and are not healthy in large quantities. We can taste the sugar very well, but how much exactly does a drink contain? How can you measure how much sugar is dissolved in a sweet drink?

Before you get started

If you are experimenting at home:
1. Let your parents know and discuss the experiments with them beforehand.
2. Do not eat or drink at your workspace.
3. Wash your hands thoroughly before and after the experiment.
4. Be careful and cautious with the materials.

Graphic figure boy pouring liquid in flask

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Two empty glasses, a glass of orange-yellow juice, a pyramid of sugar cubes, a plasticine ball, a ruler, a waterproof felt-tip pen and a thick straw on a gray table against a green background.

You will need

Slim, tall water glasses
Sugar cubes
Thick straws
Waterproof plasticine
Ruler
Waterproof felt-tip pen
Non-carbonated drinks

Let’s get started!

1. Prepare your research diver

Shape a ball of waterproof plasticine. Insert a straw into the ball of dough so that no water gets into the straw.

glass with water. A diver swims upright in a glass.

2. Prepare water glasses

Test the diver: he should swim upright without touching the wall or the floor. Remove some of the plasticine if necessary.

Drei Gläser mit Wasser; vor jedem Glas steht eine kleine Pyramide aus Zuckerwürfeln: Links 4 Würfel, in der Mitte 7 und rechts 10 Zuckerwürfel.

3. Make sugar solutions

Prepare three sugar solutions: with five, seven and ten sugar cubes in 200 mL of water each. When all the sugar has dissolved, check the filling level. It is important for the experiment that the water is at the same level in all glasses. You may have to skim off some of the water from some of the jars.

Close-up: A ruler lies on a glass and touches a blue straw. At the point where the ruler touches the straw, a mark is made on the straw with a black felt-tip pen.

4. Mark immersion depth

Dip the diver into the first sugar solution. Place the ruler on the glass and mark the point where the ruler touches the straw with a felt-tip pen. Repeat this with the other two solutions.

Close-up shot with markings on the straw highlighted

5. Test the drinks

Now dip the dipper into the drinks you want to test. Up to which mark does it dip? The comparison shows you approximately how many sugar cubes are contained.

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Flip card
What does the sugar content have to do with the immersion depth of the diver?

Answer

It has to do with something called the “density” of materials or liquids. The less space ‏(volume) a certain amount of weight ‏(mass) of a material takes up, the greater its density. A 100 g bar of chocolate is quite small. By contrast, 100 g of candy floss is quite a big pile. Chocolate therefore has a greater density than candy floss. When we add sugar to water, we also change the density of the water. The more sugar we add, the greater the density.

Our diver works like a hydrometer: The measuring principle is Archimedes' principle: a body is immersed in a liquid until the weight of the displaced liquid equals the weight of the immersed body. The higher the density of the liquid, the more buoyancy it gains and the less deeply it sinks into the liquid.