activation energy
noun
: the minimum amount of energy required to convert a normal stable molecule into a reactive molecule
Examples of activation energy in a Sentence
Recent Examples on the Web
Light also reduces the activation energy, making the reaction easier.
—
Jijo Malayil, Interesting Engineering, 15 Nov. 2025
Human cells – like all animal cells – use enzymes to lower activation energy in reactions and thus increase reaction rates.
—New Atlas, 14 Nov. 2025
Additionally, the material exhibits a low activation energy, indicating minimal energy barriers for lithium-ion movement.
—IEEE Spectrum, 15 Feb. 2024
What all of these examples have in common is that the former require less activation energy—the initial self-discipline and oomph to start something—and feel good immediately but crappy later on.
—Brad Stulberg, Outside Online, 24 May 2022
Just about everything in my life—from getting out of bed to exercising to writing to coaching to reading—required a significant amount of activation energy.
—Brad Stulberg, Time, 20 Sep. 2021
If the activation energy is too high, the reaction does not occur.
—Svenja Lohner, Scientific American, 10 Nov. 2016
The firmness of beans, which was measured by use of a tenderometer, decreases during blanching according to a first order reaction with 40 kcal/mole activation energy.
—Ncbi Rofl, Discover Magazine, 26 Nov. 2010
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Jijo Malayil, Interesting Engineering, 15 Nov. 2025
Human cells – like all animal cells – use enzymes to lower activation energy in reactions and thus increase reaction rates.
—New Atlas, 14 Nov. 2025
Additionally, the material exhibits a low activation energy, indicating minimal energy barriers for lithium-ion movement.
—IEEE Spectrum, 15 Feb. 2024
What all of these examples have in common is that the former require less activation energy—the initial self-discipline and oomph to start something—and feel good immediately but crappy later on.
—Brad Stulberg, Outside Online, 24 May 2022
Just about everything in my life—from getting out of bed to exercising to writing to coaching to reading—required a significant amount of activation energy.
—Brad Stulberg, Time, 20 Sep. 2021
If the activation energy is too high, the reaction does not occur.
—Svenja Lohner, Scientific American, 10 Nov. 2016
The firmness of beans, which was measured by use of a tenderometer, decreases during blanching according to a first order reaction with 40 kcal/mole activation energy.
—Ncbi Rofl, Discover Magazine, 26 Nov. 2010
Cite this Entry
“Activation energy.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/activation%20energy. Accessed 27 Nov. 2025.
Copy CitationMedical Definition
activation energy
noun
ac·ti·va·tion energy
ˌak-tə-ˈvā-shən- 
: the minimum amount of energy required to convert a normal stable molecule into a reactive molecule
called also energy of activation
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