attogram

What Is attogram?

An attogram is a unit for measuring very small amounts of mass. It is much smaller than a gram or even a milligram. Scientists use attograms when they study tiny things such as single molecules, very small particles, or parts of cells. In math form, one attogram is one billion billionth of a gram.

Definition

The attogram is a metric unit of mass.

• 1 attogram = 0.000000000000000001 gram
• 1 attogram = 10⁻¹⁸ gram
• 1 attogram = 0.000000000000000000001 kilogram
• 1 attogram = 10⁻²¹ kilogram

This means you would need 1,000,000,000,000,000,000 attograms to make just 1 gram. Because it is so small, you will only see it in very advanced science and technology.

History / Origin

The attogram comes from the International System of Units, called SI. In 1964, scientists agreed on a set of new size words for very big and very small numbers. One of these was the prefix atto.

The word atto is based on a word from Danish that is related to the number eighteen. This is because an attogram is 10 to the power of minus 18 of a gram. When you join the prefix atto with the base unit gram, you get the word attogram.

So the attogram is not an old unit like the gram. It is a modern unit created to help scientists talk clearly about extremely small masses.

Symbol & Abbreviation

The attogram has a short symbol used in formulas and on data charts.

• Name attogram
• Symbol ag

Notice that the symbol is written with a lowercase a and a lowercase g. This shows it belongs to the metric system and is based on the gram. You should not write AG or Ag when you mean attogram, because Ag is already the chemical symbol for silver.

Current Use Around the World

The attogram is an official part of the SI system, used worldwide by scientists. You will not see it on kitchen scales or in shops, because it measures masses far too small for everyday life.

Places where attograms are useful include:

• Chemistry to talk about the mass of single molecules or very small amounts of a substance
• Physics to describe tiny particles and parts of atoms in experiments
• Nanotechnology to measure the mass of nanoparticles and nanodevices
• Biology and medicine to measure extremely small amounts of DNA, proteins, or viruses
• Advanced sensors in research labs that can detect changes of just a few attograms

Most people will never need to use attograms in normal life. However, the unit is important in high level research all around the world, where very small masses can make a big difference in results.

Example Conversions

Here are some simple examples to help you understand how small an attogram is.

• From attograms to grams
  
  1 ag = 0.000000000000000001 g
  
  1,000,000,000,000,000,000 ag = 1 g
  
• From grams to attograms
  
  1 g = 1,000,000,000,000,000,000 ag (this is 10¹⁸ ag)
• From attograms to kilograms
  
  1 ag = 0.000000000000000000001 kg
  
  1 kg = 1,000,000,000,000,000,000,000 ag (10²¹ ag)
  

To imagine it another way, a single proton in an atom has a mass of about 0.000000000001 attogram. So even an attogram is still made up of a huge number of protons.

Related Units

The attogram is part of a family of mass units in the metric system. Here are some related units, from bigger to smaller around the attogram.

• Kilogram (kg) the main SI unit of mass
• Gram (g) 1 g = 0.001 kg
• Milligram (mg) 1 mg = 0.001 g
• Microgram (µg) 1 µg = 0.000001 g
• Nanogram (ng) 1 ng = 0.000000001 g
• Picogram (pg) 1 pg = 0.000000000001 g
• Femtogram (fg) 1 fg = 0.000000000000001 g
• Attogram (ag) 1 ag = 0.000000000000000001 g
• Zeptogram (zg) 1 zg = 0.000000000000000000001 g

Another useful unit in atomic science is the atomic mass unit often written as u. One atomic mass unit is much smaller than a gram and is often used to show the mass of atoms and molecules. Attograms and atomic mass units are both used for very small masses but in different ways.

FAQs

Q What is an attogram in simple words
A An attogram is a unit for measuring very tiny masses. It is one billion billionth of a gram, so it is only useful for things much smaller than dust.

Q How many attograms are in a gram
A There are 1,000,000,000,000,000,000 attograms in one gram. This is written as 10 to the power of 18 attograms.

Q Is an attogram smaller than a nanogram
A Yes. An attogram is much smaller. One nanogram equals 1,000,000,000 attograms. So it takes a billion attograms to make just one nanogram.

Q Where would I see attograms used
A You will mostly see attograms in scientific papers and research labs. They are common in nanotechnology, particle physics, chemistry, and biology when measuring extremely small samples.

Q Why do scientists need such a small unit
A At the scale of atoms and molecules, even a tiny change in mass can matter. The attogram gives scientists a clear way to talk about those very small changes without using very long decimal numbers.

Q Can normal scales measure attograms
A No. Normal kitchen or bathroom scales cannot detect anything this small. Measuring attograms needs very special and sensitive instruments found only in advanced laboratories.