Hydrometer facts for kids
A hydrometer is a special tool used to measure how "heavy" a liquid is compared to water. This measurement is called its specific gravity or relative density. Think of it like a floating stick that tells you how thick or thin a liquid is!
Contents
What is a Hydrometer?
Most hydrometers are made of glass. They have a long, thin top part called a stem and a wider, heavier bottom part called a bulb. The bulb is usually weighted with something heavy like mercury or small lead pieces. This weight helps the hydrometer float upright in a liquid.
How Does it Work?
To use a hydrometer, you pour the liquid you want to test into a tall container, like a measuring cylinder. Then, you gently lower the hydrometer into the liquid. It will float freely. The point where the liquid's surface touches the stem of the hydrometer is where you take your reading. Inside the stem, there's a scale that lets you read the specific gravity directly. Different hydrometers have different scales, depending on what they are used for.
Different Kinds of Hydrometers
Hydrometers can be specially made for different jobs. Here are a few examples:
- A lactometer is used to measure the density of milk. This helps to check how much cream is in the milk.
- A saccharometer measures the amount of sugar in a liquid. This is useful for things like making juice, syrup, or even brewing.
- An alcoholometer is used to measure how much alcohol is in a drink, like spirits.
- Other types can check the charge of a car battery or the freezing point of engine coolant.
Images for kids
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A 20th century Saccharometer.
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Lactometer
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Battery condition indicator to measure the charge of the battery (~1985).
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Antifreeze tester measures the freezing point of engine coolant.
See also
In Spanish: Densímetro para niños
