Archive for March, 2011

What happened to my French fries?

Monday, March 7th, 2011

Once you have grasped the theory, you are going to demonstrate your understanding by tackling the following challenge:

You are a trainee chef working in the ISM kitchens.  You have had a hard day at work, and are just about to leave for home, when your boss informs you that you will be in charge of making French fries the next day.  You are excited about the responsibility being placed on you, so you decide to get a head start and peel and slice the potatoes that afternoon.  You place the cut potato pieces into water and leave them there overnight.  When you arrive the next day, you drain the water and are surprised to find that the potato pieces are all ‘pumped up and hard’ (like Sylvester Stallone in Rocky 4).  Your boss tells you that they cannot be used to make French fries, and suggests that you should have put some salt in the water.  He gives you the task of finding out what the ideal concentration of salt in water would be for leaving the potato pieces overnight without them becoming too hard or too soft.

You must design and carry out an experiment that allows you to answer the problem above.  Use the rubrics to guide you, but you must include the following headings in your report: FINAL Rubric design  FINALRubric DCP  FINAL Rubric CE

Research Question, Hypothesis, Variables, Apparatus, Diagram, Method, Results, Graph, Conclusion, Evaluation

More on ionic and covalent compounds

Wednesday, March 2nd, 2011

ionic lattice of sodium chloride by INDIKA KUMARA on flickr

Ionic substances tend to form giant lattices.  Read this information to help you understand why.  Covalent substances can be simple molecular or giant covalent.  Metals form metallic bonds between their atoms.

This site is very useful for review and revision before your test.  Click through the different pages (parts 2, 3, 4 and 5).

Thanks to Mr Goodman for supplying these review sheets on structures and bonding.  simple mol cmpds   giant cov struc

Diffusion and osmosis

Wednesday, March 2nd, 2011

[youtube][/youtube]Ever wondered how substances move into cells, or why, when you open the front door, you can smell your favourite food cooking in the kitchen, several rooms away?  The answer is diffusion.  We’ll talk about concentration gradients to explain how smells (the nice and the not so nice!) travel through the air.  Here is a useful animation to help you understand the process.

Osmosis is a form of diffusion that deals specifically with water.  Here is a good animation to explain what is going on.  This site goes into some detail about how osmosis affects living organisms and introduces some new vocabulary – hypotonic, hypertonic and isotonic.  Make sure you know what these terms mean.  Can you explain the science behind what is happening in the video above?