6. Amazing stuff?
What are some pros and cons to single use plastic?
Pros:
โข convenient
โข Lightweight โ imagine if you had to carry all the water you use
โข Durable-items donโt break or fall apart easily
โข Cheap to make and buy
Cons:
โข Can be easily carried away by wind and easily litter the planet
โข Doesnโt break down or biodegrade easily or at all
โข Animals can ingest or get tangled in it
โข Cheap so it is easy to just make more after it is thrown away
8. Over the past week and
a half I collected all the
plastic that I would
normally throw in the
bin.
This plastic accounts for
two people in a
household.
9. Waste โRโ Us charges for their waste collection services. They use the following formula to
calculate the cost, C in pence, given the waste, W, in grams.
C = 0.5W + 4000
๏ Estimate how much will my 175g of plastic waste cost if I use Waste โRโ Us?
๏ Calculate the cost of my 175g
The 4000 in the formula is the callout charge to collect the waste.
๏ How much would it cost me per year if I could store all my waste for a single collection?
๏ What assumptions did you have to make in finding an annual cost?
10.
11. What can we do
about the plastic that
we cannot recycle?
13. Ecobricks are one of the few
ways to effectively sequester
single use plastic. Ecobricks
remove plastic from the
biosphere and from the
industrial recycling system.
Ecobricks raise ecological
consciousness and enable
individuals, communities and
companies to transition from
plastic.
https://www.ecobricks.org/why
14.
15. Changing the specification
Ecobricks4Life is looking for donations.
They require that each bottle has a density of 0.4 g/ml.
๏ How many grams of plastic should there be in each ml of a bottle?
๏ How many grams of plastic should a 100ml bottle contain?
๏ How much should every 10ml of an Ecobricks4Life
bottle weigh??
๏What is the target weight for a 330ml bottle?
16. Working with a formula
Ecobrick density specifications vary between 0.33 and 0.7 g/ml.
A formula is useful for finding weights of ecobottles
- if the calculations are to be done with a spreadsheet
- if the specification changes frequently
- If the specification is given to many decimal places
The formula for density (given by the Greek letter rho ๐) is ๐ =
๐
๐
17. Homework: How much single use plastic do
you use in a week?
โข In your jotters write down an estimate of how many grams of single use plastic
you use in a week.
โข Over the next week collect all the plastic you would normally throw into the bin
and either weigh it at home and bring in a selfie with it or bring it into class and
we can weigh it here.
โข Next week we will measure and compare our results as a class.
โข Extension: Make an ecobrick! (this may take you more than a week) Remember
each brick needs to have a density of 0.3g/ml. Collect a plastic bottle and
calculate the weight of single use plastic you would need to collect.
18. Homework follow up
Plastic Estimate: _________ Actual Plastic:__________
๏How close were you to your estimate?
๏How many eco bricks could you make from your single use waste?
๏What strategies could you try to help you reduce your waste?
19. Homework follow up
Come up and write your plastic weight in grams on the board
The formula to calculate the average plastic waste per person is as
follows:
๐ด๐ฃ๐๐๐๐๐ ๐๐๐๐ ๐ก๐๐ ๐ค๐๐ ๐ก๐ =
๐๐ข๐ ๐๐ ๐๐๐๐ ๐ก๐๐ ๐๐ ๐๐๐๐๐
๐๐ข๐๐๐๐ ๐๐ ๐๐๐๐๐๐
When we find the mean average we are sharing the total pile of waste
out equally between ourselves.
20. Could ecobricks be
a solution to
Scotlandโs plastic
waste?
Read all about it in
this news article
21. โข War on Plastic with Hugh and Anita
https://www.bbc.co.uk/programmes/m0005xh7
โข Newsround article
https://www.bbc.co.uk/newsround/42810179
โข BBC article โwhatโs the real price of getting rid of plastic packaging?โ
https://www.bbc.com/worklife/article/20180705-whats-the-real-price-of-
getting-rid-of-plastic-packaging
Editor's Notes
2 minute peer discussion.
What happens to it? If it goes to landfill it is unlikely to decompose for hundreds of years. If it is left out in daylight (e.g. floating in the sea) it will decompose but this produces tiny bits of plastic which enter the food chain and cause damage.
Have pupils come up to the board and add to a list or mind map.
Packaging, light-weight plastic bags, disposable utensils, plastic water bottles, wet wipes, and straws.
1-2 minute discussion with peers. Then have a few volunteers share with the class.
Group/pair discussion 2-3 minutes to brainstorm ideas. Then class discussion to share ideas.
Pupils should hopefully notice they need to convert the weight in tons to the weight in grams.
1ton = 1 000 000g
Assume same level of waste every week (likely to be more at e.g. Christmas)
Note โ a year is not exactly 52 weeks but rounding is not going to make a big difference here to our estimate.
Pupils may be surprised by the idea of having to pay to have your waste taken away.
0.2p per g
W x 1000 000 x 0.002 = C
2000w = C
ยฃ600m a year is approximately ยฃ100 per person
https://www.youtube.com/watch?v=cbPt1Jn3YLw
Using a multiplicative reasoning approach
1 ml contains 0.33 g
100 ml contains 33g
For every 10ml we would need 3.3g
He has a 200ml bottle so this needs 33 x 2 = 66g โ his brick is almost there
This may provoke a useful discussion about what 6g of single use plastic looks like. The peel off lid of a food package is around 1 โ 2g.
News Article About Eco Bricks in Scotland
https://www.sundaypost.com/fp/could-ecobricks-be-the-new-solution-to-scotlands-plastic-waste/
Used TTS Reader to have the article read to pupils: https://ttsreader.com/