B1.6 Waste Materials from Plants and Animals

Question 1

What is a decomposer?

Answer 1

Animals that feed on dead plants or dead animals

Question 2

What does ‘biodegradable’ mean?

Answer 2

Something that can be broken down by a living organism

Question 3

What is a compost bin?

Answer 3

Often made of plastic, sold cheaply to local councils. You water during dry weather and mix contents from time to time.

Question 4

What is a compost heap?

Answer 4

Simplest and cheapest method; kitchen and garden waste put in a pile and left to rot.

Question 5

Explain black bin composting

Answer 5

Kitchen and garden waste in a bag and secured. Microorganisms slowly (little oxygen) decompose.

Question 6

Explain council composting

Answer 6

May shred the material to increase surface area, compost will then be sold.

Question 7

What waste products do decomposers produce?

Answer 7

Carbon dioxide and water (that plants can use)

Question 8

What are some methods of preservation?

Answer 8

> freezing (stops microbes, doesn’t kill)
food can be heated (kills microbes)
vinegar makes the pH too low for microbes
drying food removes moisture that microbes need
milk is heated (pasteurisation)
salt is added to kill microbes (too much can harm humans)

Question 9

What are the optimum conditions for decay?

Answer 9

Warm
Moist
Lots of oxygen