Living Beyond Earth: teacher key

Astronauts and Space Travel, grade 11 edition, written for 11th grade. The space station makes air and recycles water, and spaceflight changes bones, fluids and eyes. The book also covers radiation, spacesuits and the long wait that a trip to Mars brings.

Read the book. Print this page for the key.

Questions and answers

1. How does oxygen for the station cabin get made?
   • Electricity splits water into hydrogen and oxygen (answer)
   • Plants make all of it
   • It is carried up in tanks only
2. Why do bones get weaker on a spaceflight?
   • Bone-breakdown cells stop working
   • Bone-building cells slow down while breakdown cells keep their pace (answer)
   • Astronauts eat less
3. If the station used 100 liters of water, about how much would have to be supplied from outside?
   • About 10 liters (answer)
   • About 50 liters
   • About 90 liters
4. A Mars crew sends a question and Earth replies right away. Up to how long could the exchange take in signal travel alone?
   • Up to about 3 minutes
   • Up to about 25 minutes
   • Up to about 50 minutes (answer)
5. In the phrase "bones get weaker and more brittle", what does brittle mean?
   • Easily broken (answer)
   • Very heavy
   • Growing fast

Words

• zeolite: gas-absorbing mineral
• electrolysis: splitting by electricity
• synodic: repeating cycle
• brittle: easily broken