Concrete
Concrete combines cement, water, sand, and larger aggregates. Cement reacts with water to form binding products: hardening is more than drying.
Practice: Matter & mixtures →Celebrate Chemistry
A year of reasons to be curious. Explore chemistry celebrations, follow a learning path, and discover the materials holding your world together.
OCTOBER 18–24, 2026
National Chemistry Week 2026
Chemistry Under Construction
National Chemistry Week is an American Chemical Society (ACS) outreach program connecting communities with chemistry in everyday life. This year’s theme explores the materials that make buildings and bridges strong, safe, and durable.
Even a small change in composition can change how a material performs. Your building has chemistry homework, too.
What’s your world built from?
Steel
Steel is an alloy based on iron. Carbon and other alloying elements, together with processing, affect properties such as strength and toughness.
Practice: Bonding & materials →Protective coatings
An intact barrier coating can slow corrosion by limiting contact with water and oxygen. Damage to the coating can expose the metal underneath.
Practice: Redox chemistry →Polymers
Long molecular chains form materials used in pipes, sealants, and insulation. Different structures give different properties; no one plastic suits every job.
Practice: Organic foundations →Insulation
Suitable insulation slows heat transfer. Many insulating materials trap gas in small spaces, reducing heat flow compared with a solid, conductive metal.
Practice: Heat & energy →Theme and construction background: American Chemical Society ↗. Original explanations and activities by Chemistry Corner; this website is not sponsored by ACS.
Young explorers: become a materials detective
Why use metal for a railing and a different material for a warm coat? Start by noticing what each material needs to do.
Materials detective: look, don’t collect
Explore a safe familiar place with an adult, or use pictures. Find examples of four materials and explain their jobs.
Safety first: Stay away from construction sites. Do not collect, chip, taste, heat, or mix materials. Ask an adult. For any linked lab activity, wear goggles and follow its instructions; never mix unknown chemicals.
Reveal the chemistry clue
The metal supplies support; the coating can help protect it. Do not scratch the surface to investigate.
Reveal the chemistry clue
Concrete is a composite mixture. The binding cement chemically reacts with water while it cures. Look without chipping or collecting it.
Reveal the chemistry clue
Many plastics are polymers. A recycling or material label is useful evidence; appearance alone cannot identify a polymer.
Reveal the chemistry clue
Ask which parts slow heat flow. Different materials serve different jobs. Do not open walls or touch exposed insulation.
0 of 4 examples explored. Progress is for this visit only.
Give this railing a longer life
A steel railing will stand outdoors in damp air. Which choice best helps slow corrosion?
Keep exploring with activities already here
Meet iron and other elements · Rotate a molecule · Explore virtual experiments
ACS 2026 activities: foam building and material fractures ↗College students: connect structure with performance
From atoms to infrastructure
Use mixtures to describe concrete, bonding to compare materials, and reaction equations to describe chemical change.
Then connect electrochemistry with corrosion, organic foundations with polymers, and heat transfer and energy with insulation.
Design for a longer life
Compare two options for a building component. Consider durability, maintenance, material use, energy, and eventual reuse or disposal. A lower initial mass does not automatically mean a lower lifetime environmental impact.
Mole Day: October 23
Mole Day is celebrated annually, traditionally from 6:02 a.m. to 6:02 p.m. The time and the date 10/23 play on approximately 6.02 × 1023 particles per mole. October 23 falls within National Chemistry Week in 2026.
In plain English: A dozen means 12 things. A mole is another counting unit, but it means an unimaginably larger number of things. Always name what you are counting—atoms, molecules, ions, or other entities.
Chemistry celebrations calendar & archive
Educational celebrations, not a list of federal holidays. National Chemistry Week, Mole Day, Periodic Table Day, and CCEW focus on chemistry; Earth Day itself has a broader environmental focus.
Dates and labels use America/Chicago. Annual Mole Day and Periodic Table Day recur on fixed dates; ACS week dates and themes below are individually verified.
Checking today’s Central Time date…
Sources & further discoveries
The 2026 feature and listed dates were checked on October 19, 2026. Future dates and themes need fresh source verification; the 2026 feature remains available after the week ends.