Three Theories of a Yawn: teacher key

Hiccups, Sneezes and Yawns, grade 6 edition, written for 6th grade. Scientists can explain a sneeze and a hiccup in some detail. For yawns, they offer three theories and no settled answer.

Read the book. Print this page for the key.

Questions and answers

1. What does the NHS say about home hiccup tricks?
   • There is no evidence they work for everyone (answer)
   • There is proof they cure hiccups
   • They were tested in space
2. What do sensory nerves do at the start of a sneeze?
   • Close the vocal cords
   • Send the alarm (answer)
   • Cool the blood
3. Which of these is one of the three main theories of yawning?
   • It warms the lungs
   • It clears the nose
   • It sends a message to others (answer)
4. Why does the arousal theory fit yawns being common when people are drowsy?
   • It says yawning helps wake the brain up (answer)
   • It says yawning spreads germs
   • It says yawning makes air colder
5. Why is the brain-cooling idea called a theory?
   • It is not a settled answer (answer)
   • It was proven in a lab
   • It only applies to dogs
6. What can the communication theory help explain?
   • Why hiccups stop
   • Why yawns spread (answer)
   • Why we sneeze in light

Words

• reflex: automatic action
• diaphragm: breathing muscle
• arousal: waking up
• communication: sending messages