This demo is part of the STAO demo collection available free of charge on our website.
Primary industry has been important to the Canadian economy for hundreds of years. In particular, the vast forests in British Columbia and Ontario provide the raw materials for a billion-dollar industry. Forests are also environmentally important as they remove carbon dioxide from the air and replenish the atmosphere with oxygen. Each forest is a diverse community of different plant and animal species. In addition, the roots of trees and vegetation help to absorb water, limiting rain runoff and reducing soil erosion.
There are a several different logging practices, each with economic and environmental advantages and disadvantages:
- • Clear cutting: involves the removal of all trees and vegetation in the area. Although it is the cheapest method of logging, the environmental impact is severe.
- • Shelter-wood cutting is the staged harvesting of strips of trees. Seed-bearing trees are left to regenerate and wind damage is reduced but erosion along the strips is still a problem.
- • Patch cutting involves selectively cutting 100-200 ha patches of trees, leaving connectivity between the remaining forest. It is costly because specialized equipment is required, but less environmentally damaging.
- • Selective cutting is the removal of only the most desirable trees from the forest. This has the least impact on the forest however it is very costly.
This demonstration simulates the effects of the removal of vegetation on erosion of soil in an ecosystem.
Click here to download the complete demo…..
Color perception limited to a surprisingly few number of retinal cells. Read more: http://scim.ag/2cZWrc9
Last time CO2 was this high, humans didn’t exist – click here
Shifting baselines – click here
Earlier this summer Health Canada issued an advisory warning about the potential health hazards of using Borax (see link below).
This advisory is of particular concern to science teachers since making homemade “slime” is a common activity that may involve the use of borax.
Information Update – Health Canada advises Canadians to avoid homemade craft and pesticide recipes using boric acid
One approach to dealing with this issue is to look for slime recipes that involve safer alternatives. Check out this link for one possibility
Thanks to humans, larger marine animals likely to go extinct; keeping TV science honest; controlled “firenadoes” could be put to good use; science hasn’t played a big part in 2016 presidential election; colour vision might work differently than previously thought; season’s first harvest moon – just a few of the themes in today’s eclectic collection of SciNews. Share these stories with your students and get them excited about science.
A lever is one of six simple machines. All machines, no matter how complex, are forms of simple machines. Machines allow people to perform useful work or a specialized task. Levers, in particular, are used to reduce the amount of force required to move heavy loads. Examples of levers include crowbars, seesaws, wheelbarrows, and tongs.
Food fraud often boils down to politics or semantics. Something labeled parmesan cheese may not come from Parma, for instance. But sometimes food producers try to feed us cheap fillers and other lies. In this episode of Speaking of Chemistry, Sophia Cai explains how scientists, regulators, and food makers are relying on chemistry to make sure consumers get what they pay for.
Want to learn even more about fighting food fraud? Check out these great resources.
Parmesan test can detect cheesy imposters | C&EN
Autheticating Food | C&EN
Food Safety Gambit | C&EN
The Parmesan Cheese You Sprinkle on Your Penne Could Be Wood |Bloomberg
Guilty pleas filed in federal criminal fake cheese cases | Food Safety News