Where the Gas Comes From: teacher key

Burps and Farts, grade 5 edition, written for 5th grade. Gas inside your body has two sources: air you swallow and food that tiny bacteria break down. Find out how each one ends up as a burp or a fart.

Read the book. Print this page for the key.

Questions and answers

1. What happens to most swallowed air?
   • It is turned into food
   • It comes back up as burps (answer)
   • It stays in the large intestine
2. Where is most of the gas that comes out of the bottom made?
   • By bacteria in the large intestine (answer)
   • In the mouth
   • In the lungs
3. Why might beans make more gas than some other foods?
   • They have no smell
   • Bacteria work on fiber the body cannot fully digest (answer)
   • They make you swallow air
4. What does ferment mean on these pages?
   • To swallow air
   • To break down food and give off gas (answer)
   • To smell strongly
5. What is often the reason a fart smells?
   • Sulfur (answer)
   • Oxygen
   • Nitrogen
6. Why can two people at one table have different amounts of gas?
   • Only one of them has bacteria
   • Air and food choices differ (answer)
   • Only grown-ups make gas

Words

• bacteria: tiny living things
• ferment: break down food
• fiber: plant food parts
• lactose: milk sugar
• sulfur: smelly mineral