A Fish With a Speed Limit: teacher key

The Fastest Animals, grade 9 edition, written for 9th grade. The sailfish was said to swim 68 miles an hour. Muscles, bubbles and old fishing lines tell another story.

Read the book. Print this page for the key.

Questions and answers

1. Where did the 68 miles an hour sailfish number come from?
   • A 2016 muscle study
   • A Florida fishing trial in the early 1900s (answer)
   • A radar gun
2. What limits how fast a fish's tail can beat?
   • The color of its fins
   • The depth of the sea
   • How fast its muscle can twitch (answer)
3. Why does a record that comes from acceleration not show top speed?
   • It comes from a brief burst, not a speed kept up (answer)
   • It is measured in the wrong unit
   • Fish cannot accelerate
4. Which shark is considered the fastest?
   • The whale shark
   • The nurse shark
   • The shortfin mako (answer)
5. What does the word acceleration mean here?
   • Slowing down
   • Speeding up (answer)
   • Resting

Words

• twitch: quick squeeze
• acceleration: speeding up
• countercurrent: opposite flow
• streamlined: smooth, slim