A scientist is measuring the decay of a radioactive substance. The substance initially weighs 200 grams, and it decreases by 15% every hour. How much of the substance remains after 4 hours?

Sun, 10 May 2026 18:38:40 +0000

**Discover Hook: The Science of Loss Measured in Real Time**
Curious about how materials in nature change—especially in fields like medicine, energy, and environmental science? A scientist measuring the decay of a radioactive substance offers a clear window into one of nature’s most precise and predictable transformations. With 200 grams of material starting the journey and losing 15% of its mass each hour, this isn’t just a math problem: it’s a real-world example of exponential decay with clear, measurable stakes. Behind the numbers lies a process central to radiometric dating, nuclear medicine, and safety protocols—making this a topic people are actively exploring. --- Why A Scientist Is Measuring the Decay of a Radioactive Substance
The concept of radioactive decay is more than textbook: it’s a critical field shaping health, technology, and environmental science. In the US, growing interest in nuclear power, radiation safety, and scientific literacy fuels curiosity about how scientists track the gradual loss of radioactive materials over time. The steady 15% hourly decrease exemplifies exponential decay, a model used across engineering, archaeology, and medical diagnostics. With so much reliance on precise decay calculations, understanding even the basics supports informed public discourse—and even personal awareness. ---