Archive for the ‘G9 Int Sci’ Category

DNA – what does it stand for?

Tuesday, April 5th, 2011
YouTube Preview Image

Deoxyribonucleic acid – that’s what.  It is the magic code that describes all living organisms.  Did you know that bacteria, plants and animals all share the same genetic material?  The language of DNA has only 4 letters, and yet we still see millions of different species and variations within species.

To help you learn about the structure of DNA, you can read this and this.  We will also attempt to extract DNA from strawberries.  Here’s how.  And this is the rubric for writing out the method etc. Communication rubric for extracting DNA from strawberries lab

Looking at cells

Wednesday, March 30th, 2011

cheek cells by Ah Pao on flickr

This week we’ll be getting the microscopes out and you will be making your own slides of different cells.  On the link below you will find the instructions for how to do this.  I suggest you read them before class.  This will save you time in the lesson, and you will be able to make more slides 🙂

Observing cells with light microscopes

plant cells leaf by Ah Pao on flickr

Once you have made your slides, you will be expected to draw biological diagrams of what you observe.  The rubric that will be used to assess these drawings is here:

Grade 9 Rubric for the marking of scientific drawings 

Cell structure and diversity

Wednesday, March 30th, 2011

nerve by estherase on flickr

Take some time to click through this site to learn more about cells and their structures.   Here is another good place to learn about cells.   Look through each site and then leave me a comment as to which of them you preferred and WHY

If you find any other sites on this topic that you think would help your classmates learn, please include them in the comments too.

Here is a link to a quiz that you can use to check your understanding of cells.  It is brief – my advice is that you study the structure of prokaryotic and eukaryotic cells, and their functions, and their differences, then see how you go on the quiz.  The answers are on there too, so you can self-assess.

Quiz – cell parts and their functions

What do all cells have in common?

Why do cells differentiate?  Within the same organism, there are differences between cells – why is this?

Here’s what you need to do:-

  1. In your groups, make a list of all the different types of cells you can think of (eg, red blood cell, leaf cell)
  2. Each student chooses ONE cell type to research.  Draw the basic structure, state its function, describe why it is unique, and where it is found.
  3. Share your findings with your group.
  4. Discuss the similarities and differences between the cells you described.  Are cells more alike or more different from one another?  Are some cells more complex than others?  Which ones? 
  5. Try to explain why cells have these similarities and differences.

Cell structure

Wednesday, March 16th, 2011

cells by Dougal Campbell on flickr

Watch this brainpop video on cells to introduce the topic.  For more detail on cell structures, watch this.   For comparisons on plant and animal cells and cell specialization watch this.

You need to be able to do the following:-

  • Draw and label a diagram of a simplified animal cell.
  • Draw and label a diagram of a simplified plant cell.
  • State the functions for each of the labels on the above diagrams.
  • Compare animal and plant cell structure and relate to their functions.
  • Understand that cells are differentiated for their functions, and give some examples of these specializations.

Historical biology or biological history?

Friday, March 11th, 2011

microscope by staceyjoy on flickr

This week we’ll be looking at the development of the cell theory.  You will need to research the contribution made by each of the following scientists, find a picture of the person or what they made or saw, then use the information to construct a timeline.  Put all that into a presentation of some kind  [prezi / dipity /anything else appropriate].  Your presentation should also include the main points of the cell theory.  Enter the url of your work as a link in a comment on this post.

1.      Hans and Zacharias Janssen

2.      Robert Hooke

3.      Anton Leeuwenhoek

4.      Matthias Schleiden

5.      Theodor Schwann

6.      Rudolf Virchow

7.      August Weismann

Can you label the parts of the microscope on this drawing? Parts-of-a-microscope

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

Peer assessment of lab work

Wednesday, February 23rd, 2011

Spectacle chandelier by seq on flickr

We’ll be doing an experiment to compare the properties of ionic and covalent substances, and to then relate these properties to the types of bonding in them.  Here’s the instruction sheet: LAB – How are the properties of substances explained by theories of bonding and structure

Once you have written up the lab report, you will peer assess it using these rubrics.  FINALRubric DCP   FINAL Rubric CE  The first one (DCP) looks at your data collection.  The second one (CE) looks at your conclusion and evaluations.  A few of your classmates can give you feedback, which you can then act on before you submit the final version to me.

Lewis structures and bonding

Tuesday, February 15th, 2011

Carbon dioxide octet dot cross from wikimedia commons

As a good introduction to bonding, watch this and sing along!

An ion is a charged atom – one that has gained or lost electrons in order to complete it’s outer shell and become stable.  Elements in Group 1 form ions with a charge of +1, since they lose 1 valence electron and end up with one more proton than electron.  Elements in Group 7 form ions with a charge of -1, since they gain 1 valence electron and end up with one more electron than proton.  The bond that is formed when a metal and a non-metal react in this way is called an ionic bond.  In an ionic bond, electrons are donated or received.

Covalent bonds form between non-metal elements.  This could be between the same non-metals (eg. O2) or different non-metals (eg. CO2).  In a covalent bond electrons are shared between the elements to complete the outer shells.  We use Lewis structures to represent this.  Click here for instructions on how to draw Lewis structures (also known as “dot and cross” diagrams).

To practice drawing these diagrams, here are some useful links:-

This site allows you to build your own molecules with single, double and triple covalent bonds.  If you don’t do any others, DO THIS ONE.

This one wold be good for review at the end of the topic.  It generates some multiple choice questions for you to practice identifying the correct Lewis structure.

Finally, this site allows you to construct Lewis diagrams.  It is quite advanced, but some of you might enjoy the challenge 🙂

Periodic Table

Thursday, February 3rd, 2011

Periodic Table on a taxi by geofones on flickr

We need to get to know the Periodic Table very well.  To help us we will use the following resources (thanks Mr Goodman!) and this linkThis site will also be invaluable to recap what we talk about in class.

mendeleev

The_periodic_table

patterns in PT

And here is a homework assignment for you.  PT_scavenger_hunt

We will talk about trends and patterns in the periodic table, specifically Group 1 (alkali metals) and Group 7 (halogens).  We will make observations about reactions of the alkali metals with water.  Li and Na we can do in class, but for the more reactive elements we’ll have to be content with watching this video.

Atomic structure

Tuesday, January 25th, 2011

Sodium2 by Mrs. Pugliano on flickr

We’ll kick off our new unit on STRUCTURES by looking at the structure of the the atom.  YOU KNOW THIS STUFF ALREADY so the first part will be a recap, then we’ll go beyond the material you covered in Grade 8.

Here’s the presentation we will use in class: KS4 The atom

And here are some practice worksheets to see if you have understood the concepts.  DO THEM! struc of atoms1   basic at struc

This is a useful resource to help you get up to speed with these ideas.

More resources: A Few Definitions   Atomic Structure Projections

Elements_compounds_or_mixtures