The Hot Paperclip
Ana bends a paperclip back and forth twenty times. The bend becomes hot enough to feel, yet nothing was added to it.
Where did the heat come from, if nothing went in?
Page 1
Science · Grade 8 Science
Chapter 1: Atoms and the Particle Model
Temperature is a measurement of how fast they move.
Ana bends a paperclip back and forth twenty times. The bend becomes hot enough to feel, yet nothing was added to it.
Where did the heat come from, if nothing went in?
Make your guess to turn the page.
Still to come: 10 pages · Words to Know · What We Learned · 4 questions · Explain It in Writing · Ask and Wonder
The idea this lesson is working on — Students talk about heat as a stuff that goes into things, and everyday language ("let the heat in") supports them. The book first turns a correlation (warm fingers always present) into a test of cause by using pliers, then reads a slope of 0.5 °C a bend. Ask: if heat came from the fingers, what should the pliers do? The idea to reach is that temperature measures particle motion, and heating is a transfer of energy, not of stuff.
Average, and heat against work — Temperature is proportional to the average kinetic energy of the particles; at any temperature some move much faster than others, which is why evaporation happens below boiling. Physicists reserve "heat" for energy transferred because of a temperature difference; bending and drilling transfer energy by doing work. The distinction is kept light for this age.
About the numbers — Rumford reported in 1798 that water around a cannon being bored reached boiling in about two and a half hours. A paperclip bent repeatedly at one point can warm by 10 to 20 °C; the steady 0.5 °C per bend is a realistic illustration, not a published study. A sparkler spark is roughly 1,000 °C or more but has so little mass that it holds very little energy.