Breaking the Chain: teacher key

Germs, grade 8 edition, written for 8th grade. An infection needs five steps to happen, and handwashing breaks one of them. See how that works, what the numbers show, and how a moldy dish led to a medicine.

Read the book. Print this page for the key.

Questions and answers

1. At which step does handwashing break the chain?
   • The reaction step
   • The multiply step
   • The travel step (answer)
2. When were compound microscopes invented?
   • In 1928
   • Around 1595 (answer)
   • After Leeuwenhoek was born
3. Why does herd immunity protect people who cannot be vaccinated?
   • It makes it harder for disease to reach them (answer)
   • It makes them healthier
   • It gives them antibodies
4. What did Fleming conclude from the plate?
   • The bacteria made the mold
   • The plate was dirty
   • The mold made something that works against bacteria (answer)
5. In this passage, what does multiply mean?
   • Get smaller
   • Grow in number (answer)
   • Move away

Words

• infection: germs causing harm
• multiply: make many more
• vaccinated: given a vaccine
• antibiotics: bacteria-killing medicines
• lenses: curved glass