Timed to the Second
Leo's tablet took 184 s to dissolve in water at 20 °C, and Sam's took 47 s, both timed to the second. Sam's water was at 60 °C, and he had crushed his tablet to powder.
What made Sam's tablet dissolve faster?
Page 1
Science · Physical Science
Chapter 1: Measurement and the Nature of Science
A precise result can still support nothing.
Leo's tablet took 184 s to dissolve in water at 20 °C, and Sam's took 47 s, both timed to the second. Sam's water was at 60 °C, and he had crushed his tablet to powder.
What made Sam's tablet dissolve faster?
Make your guess to turn the page.
Still to come: 9 pages · Lab · Words to Know · What We Learned · 4 questions · Explain It in Writing · Open Questions
The idea this lesson is working on — Students judge an experiment by the care of its measurements, because care is what they can see in the data. The book sets that against two precise times that support nothing, and against the same apparatus run with one change, which supports a clear claim. Ask: list everything that differed between the trials; how many entries are there? The idea to reach is that the design, not the precision, decides what a result can mean.
Repeat, then look at the spread — Three runs that agree closely support the result; three that scatter widely mean something uncontrolled is at work. The lab gives one time per trial, which is a simplification. Lind’s 1747 trial is often called the first controlled clinical trial; it had two sailors per arm and no randomization, which is why his own conclusions about scurvy stayed muddled.