SciNews, Thursday, October 13, 2016

Bromeliads are superstars; Neandertals are not a dead-end species; Nobel Prize for molecular machines; environmental fallout of microplastic pollution; how heat moves; Europa may be venting water into space – 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.

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Tissues, Organs, and Systems of Living Things Demo

2013-05-24_sci10_is-bigger-better-014-albertaCells require a constant supply of glucose and oxygen to produce energy. As a result of this process, large quantities of waste carbon dioxide must be expelled from the cell. All materials involved in this reaction are either imported or exported through the cell membrane by diffusion.

In this demonstration, students soak agar “cells” containing phenolphthalein indicator in a solution of sodium hydroxide, NaOH(aq). Students observe the effect of cell volume and surface area on the extent of diffusion of the sodium hydroxide solution through the “cell”.

Click here to download the complete demo….

 

Friction Activity Grade 4-6

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Friction is the force that resists the movement of one material over another. It occurs when objects rub against each other. Friction is a force that is beneficial for many everyday activities, such as walking without slipping, the operation of brakes for vehicles, or writing on a chalkboard.

Some of the harmful effects of friction include the wearing out of shoes and clothing because of rubbing together, overheating of machine parts because of too much friction or increased work because extra force is needed to overcome friction.

It is often possible to increase or decrease the amount of friction between two surfaces. Friction between two surfaces can be reduced by making the surfaces smoother or by adding a lubricant such as oil, grease, soap or wax between the surfaces.

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