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How do you measure it transparent background banner image

Much of the world around us would be a mystery without good measurements. Whether it’s the depth of the ocean, the nutrients in your cereal, or the age of dinosaur fossils, measurements enable us to learn about our world and make good decisions about what to do in everyday life. In our “How Do You Measure It?” web series, we answer questions that will help you better understand how our modern world works — and why good measurements play an important role in your life.

Illustration shows a truck driving along a road and a cow in a field, along with an oil well and a factory with smokestacks. It reads: Greenhouse Gases.

How Do You Measure Greenhouse Gases?

See Answer
Illustration shows firefighter helmet, glass of water, steak and lettuce, and a raincoat, and reads: HDYMI? PFAS [FOREVER CHEMICALS]

How Do You Measure PFAS?

See Answer
age of a tree disgram

How Do You Measure the Age of a Tree?

See Answer
Illustration shows the path of a laser moving between large and small spheres and reads: Strength of Gravity

How Do You Measure the Strength of Gravity?

See Answer
Illustration labeled "Cholesterol" shows french fries and eggs alongside a test tube and test results.

How Do You Measure Cholesterol in Blood Tests?

See Answer
Icons showing a test tube and an envelope; a grid and a DNA helix; and a globe with person markers appear over the words "DNA ANCESTRY."

How Do Companies Measure DNA to Discover Your Ancestry?

See Answer
Illustration shows a tape measure stretched out with a laser beam across it and says "Tape Measure."

How Do You Ensure That a Tape Measure Is Accurate?

See Answer
Three baskets filled with peppers. Scale on top that shows heat rating. Words say: HDYMI? "heat" of a pepper

How Do You Measure the 'Heat' of a Pepper?

See Answer
Illustration shows thermometers in a box, clouds and the Sun with the words "Air Temperature."

How Do You Measure Air Temperature Accurately?

See Answer
Illustration shows grocery items like meat, broccoli and bananas on the checkout counter with the words "Grocery Pricing."

How Do You Know If Grocery Store Scales Are Accurate?

See Answer
Illustration for ocean pH shows a ship with a testing device and red circles with H+ inside.

How Do You Measure the Acidity (pH) of the Ocean?

See Answer
Illustration shows a clock, waves moving through dots, and the word "TIME."

How Do You Measure a Second?

See Answer
Illustration says "Body Armor" with images of bullets, vests and chemical formulas.

How Do You Test Body Armor?

See Answer
Illustration shows a generator, a detector and molecules with the words "Carbon Monoxide."

How Do You Detect Carbon Monoxide?

See Answer
Updated rocket thrust banner image

How Do You Measure the Thrust of a Rocket Engine?

See Answer
Animated illustration of kitchen appliances showing toast popping up and soundwaves coming from smoke alarm is labeled "HDYMI? Detecting Smoke."

How Do Smoke Alarms Detect Fires?

See Answer
Illustration shows brewing equipment and bottles over the words "Alcohol percentage."

How Do You Measure the Percentage of Alcohol in Beer, Wine, and Other Beverages?

See Answer
GPS Location Banner Image

How Do You Measure Your Location Using GPS?

See Answer
Nutrition Labels Banner Image

How Do You Know Your Food’s Nutrition Label Is Accurate?

See Answer
Ocean Depth Banner Image

How Do You Measure the Depth of the Ocean?

See Answer
Age of Things Banner Image

How Do You Know the Age of Fossils and Other Old Things?

See Answer

Do you have a question you'd like us to answer? Contact HDYMI editor benjamin.stein [at] nist.gov (Ben P. Stein) and your question could show up in a future update to this site!