Learning Strategy: Back Checking
Everybody makes mistakes. Even the best student sometimes mixes up numbers, forgets to carry the two, hits the wrong key on the calculator, or misspells a common word. What separates the excellent student from the mediocre is often that the excellent student makes the effort to back check or double-check his or her work for errors.
This can take many forms. In writing, it is called proof-reading. In math it may involve making estimates or re-calculating each step, in history or social studies, it may be double-checking a date or name. In science, a review of units may reveal that the wrong units were used. When doing a chemistry experiment, the good students borrows from the carpenter’s adage: measure twice, cut once; in the case of chemistry, it involves double checking the names and amounts in the instructions as well as the measured amount.
Proofreading takes a different kind of mindset from regular reading. This is particularly important when one is reading what she has written. The mind already knows what the author is trying to get across and therefore may miss omitted words or a wrong verb tense. It is important to make oneself slow down, focus one word at a time for spelling, back track and place the subject of the sentence with the verb to check that the verb is conjugated correctly and the correct tense. One learns to linger over certain key words and punctuation, looking for missing apostrophes, contractions, numbers that ought to be spelled out, and dangling prepositions.
In math, the first thing one needs to do after copying a problem from the text to the page for solving is to make sure it is copied correctly. You can’t get to the correct answer if you don’t start from the right place. It is important to write out the steps taken to solve an equation or simplify an expression, so that one can review each step for math errors, sign changes, and miscopied terms. Estimates, where possible, also help determine that one has an answer that makes sense.
Whatever the subject, take the time to get it right. Back check everything. Make it a habit and you’ll feel more confident about everything you do.
News from the World of Science
Recyling Pets? No! That's Recycling PET (polyethylene terephthalate)
Do you recycle? We are quickly learning the limits of our planet. We have used up significant amounts of the world's non-renewable resources in just a century or so, and much of that has been countries like the USA. When it comes to resource conservation, it is good to remember the three R's: Reduce, Reuse, and Recycle. Whenever possible, do not use a resource if you can do without. For example, rather than leave your car running as you crawl toward a carryout window, park the car and walk into the restaurant. Reuse what you can rather than throwing things away. Keeping a supply of cloth bags in the car for grocery shopping means no new or recycled resources need be used. What you can't reuse, recycle rather than just throwing it away.
In the late 1960s, the movie character of Benjamin Braddock (aka The Graduate) is given some serious advice from one of his father's friends. He sums it up in one word: plastics! That was before ecological awareness prompted people to also think about recycling.
Since then, we have become quite fond of the plastic bottle. Most drink bottles are now made of polyethylene terephthalate, usually abbreviated PET. Plastic in any form requires petrolium to make. Petroleum is a non-renewable resource, so it needs to be conserved as much as possible. What happens to your PET containers when you chuck them into the recycle bin?
NPR recently reported on an increase in recycling of PET. The report notes that only 23% of PET bottles get sent for recycling. The rest go to land-fills where they do not decompose and contribute to the diminishing places we can store trash. What does get recycled mostly gets made into pellets that are used to make synthetic fibers. They also get made into automobile parts and even into bottles. There is demand for the recycled PET so enterprising companies are "mining" the urban environment for as much as possible.
For more information on the recycling of PET, see the following link: Kenplas.com.
For more about PET, see the following links:
History of PET
Physical Properties of PET
Safety of PET (non-plastics industry report)
Safety of PET (plastics industry report)
More on PET from Wikipedia