CK-12 Physical Science Concepts - For Middle School

1.20. Hypothesis http://www.ck12.org

FIGURE 1.24

Both the elephant and the boy are falling

to the ground because of gravity. The

force of gravity (Fgrav) is greater for the

elephant than it is for the boy because

the elephant is much more massive.

Nonetheless, both of them will reach the

ground at the same time (assuming they

fall from the same height at the same time

and there is no air resistance.)

Summary

• In science, a hypothesis is an educated guess that can be tested with observations and falsified if it really is
  false.


• You cannot prove conclusively that most hypotheses are true because it’s generally impossible to examine all
  possible cases for exceptions that would disprove them.

Vocabulary

• hypothesis: Potential answer to a question that can be tested by gathering information.

Explore More

Do the practice quiz on scientific hypotheses at the bottom of this Web page. Be sure to check your answers.

http://www.batesville.k12.in.us/physics/phynet/aboutscience/hypotheses.html

Review

1. Identify the role of the hypothesis in science.


2. State two criteria of a scientific hypothesis.


3. Which of these two statements meets the criteria of a scientific hypothesis?
   a. Acids turn red litmus paper blue.
   b. All life in the universe exists on Earth.


4. Why is it usually impossible to prove that a hypothesis is true?