Mathematics 7
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## WORKING ON WASTE AT SCHOOL

### INTRODUCTION

There are many different ways to take care of and protect the environment. What are some of the things you can do to preserve and protect the environment at home and at school?

### MATERIALS

grid paper

a ruler

coloured pencils

a calculator

Your class has been chosen to be the start-up class for a vermicomposting program at your school. Vermicomposting means composting with worms.

The principal of your school would like your class to do some Internet research on the subject and make a presentation using the data you find. You will need to find out the following:

• general information on vermicomposting
• the quantity of worms and bins you would need for one classroom
• the number of classrooms that will be vermicomposting after one year
• the amount of castings your worms will have produced after 36 weeks and after 90 weeks.
1. Use the Web links below to research and write a brief report on one of the following aspects of vermicomposting. Then present your report to the class.

1. possible building materials for bins
2. types of bedding material and the quantity needed
3. what foods to feed your worms
4. feeding techniques
5. harvesting the compost
6. possible problems and how to solve them

Click on the following links to find out more about vermicomposting. Consult at least three sites for your research.

SWRC - Vermicomposting

Compost Action Project: Vermicomposting

Featured Themes - Waste

Composting with Worms

TIP: When you are looking for specific information on a Web page, scan the text instead of reading all of it from start to finish. To begin, do not read every word of the texts but look through them quickly. For example, if you are looking for information on what to feed worms, look at the section headings first and focus on sections that are related to this subject, such as a section titled "Feeding Worms".

1. Use the information on the Web sites to decide on the number of bins and the quantity of worms (in kg) you will need for your class. Be sure to include the size of the bins in your answer. Explain your thinking and show all your work.

Keep the following in mind when making your decision:

You will be creating waste from only one meal a day and snacks, five days a week. So divide the number of people in your class by 2 since you will be producing about half as much waste as an average person.

Some students will need to volunteer to take care of the worms at their homes over the holidays and the summer. This means the bins need to be appropriate for an average-sized family.

1. Worms reproduce at a rapid rate, which is good news because the more worms you have, the more classes you can get vermicomposting.
1. Using the information below, decide how many bins you could set up after one school year (from September to June).

Worms are able to reproduce at two months old.

Worms double in number every two months.

When you have double the number of worms, you need double the number of bins

1. Complete the table of values to display your results.

2. Write the rule for the pattern.

3. How many classrooms will this number of bins supply?

1. The castings that the worms produce can be used as fertilizer. 450-600 worms can produce 18 litres of castings in 9 weeks.

1. Click on this link Compost Action Project: Vermicomposting to find out how many worms are in a half a pound.
2. How many litres of castings can 1 pound of worms produce? How many pounds of worms does your class have?

3. Complete the table of values to show the minimum amount of castings your worms could produce in 36 weeks.

4. Write a pattern rule for the number sequence in the table.

5. Write the next four terms in the sequence.

6. Create a scatter plot to predict the minimum amount of castings your worms could produce in 90 weeks.

 TASK CHECKLIST Did you include a diagram, tables of values, and a scatter plot? Did you show your steps and explain your thinking? Did you use appropriate math vocabulary?