Surface Area to volume ratio 

Today we study the relationship between surface area and volume in organisms.  

We started with a cut-and-paste activity creating cubes with sides of 2.5 cm by 2.5 cm.  

surface area

    • In words, the surface area of a cube is the area of the six squares that cover it. The area of one of them is a*a, or a 2 . Since these are all the same, you can multiply one of them by six, so the surface area of a cube is 6 times one of the sides squared.

      1. synonyms: outsideexterior.

        the area of an outer part or uppermost layer of something. 

        noun: surface area “the surface area of a cube”


        the amount of space that a substance or object occupies, or that is enclosed within a container. 

        “the sewer could not cope with the volume of rainwater” 

        cube = a 3 


DNA,  RNA and Protein synthesis 

We are studying the structure of DNA. 

DNA extraction from strawberry. 

Materials needed: Zip lock bag, two strawberries, 30 ml water, teaspoon dishwashing liquid (detergent), 2 ml salt, sieve

Step 1: Place strawberry in zip lock and squish. 

Step 2: Mix salt, water and detergent.  Add to zip lock.  Mix with strawberry mush. 

The detergent dissolves the phospholipid layers of the membranes. The salt makes the DNA less hydrophilic.

Step 3: Filter the liquid into the glass beaker using the sieve. 

Add approximately 2 cm cold methylated spirits slowly on top of the strawberry extract.

Use toothpicks to twirl the DNA out of the methylated spirits.

Building a DNA model

School improvement 

While working on our School improvement strategy I had a few challenges to face.  Our school decided to go back to our traditions and we started in the hostel by reapplying stricter rules and guidelines,  while establishing trusted routines.  The current generation of learners now feel that it is cruel.  

Are having high expectations of achievement and behaviour in learners cruel? No.   They are simply what parents pay thousands for in private schools all over the world. This would mean that any institution supporting sustained and successful learning should be considered cruel.  

It should not be that difficult to replicate the success of other schools that already follow this strategy. Our sister school definitely has a long established successful track record. Almost every city in the country already has schools like this, they just aren’t open to everybody. It should be an aim to create a state comprehensive with this sort of ethos in every local authority.

We need to stop accepting that working class kids cannot behave. It really isn’t true. They just need help and support. We need to acknowledge how many schools including our own routinely excuse the unacceptable.

Change is never easy but success is worth it.  

Die saga van ‘n karamel 

Weereens het die merk van matriek vraestelle baie interessant geraak.  Hier is so ‘n voorbeeld.  

Die vraag was oor spesiasie in kamele en waarom daar verskille is in hulle voorkoms.  Hier volg die mees traumatiese antwoord :

Tumsi die karamel

Eendag lank lank gelede was daar ‘n karamel met die naam van Tumsi. Sy ma was ‘n volstruis en sy pa was ‘n bok. Sy ouma, die Archaeopteryx is ontdek in Kimberley se gat.  

Tumsi en sy familie het besluit hulle moet emigreer. Terwyl die familie trek het hulle besluit hulle moet water stoor.  Hulle kom aan by die eerste rivier en drink.  Toe kry hulle hul eerste groot bonkel.  Hulle kon swem want die lang  wimpers het die water uit hulle oë gehou. Toe stap hulle baie baie ver. By die tweede rivier in Oos China drink hulle genoeg en vorm twee klein knoppels. Toe gaan hulle dood en word fossiele, maar verhuis  met  Darwin op die skaap (ship)  “Dromedarus” tot in Australië.  

Introduction to Life Science 

I have finally been able to sit down and create some new  images to use in my PowerPoint presentation on Introduction to Life Science for Grade 10. 

Perhaps it was the dawning of the new year,  I just felt absolutely inspired.  Here are just a few examples : 

NTA standards? 

This year was the third AND LAST time I participated in the National teaching awards event held annually in South Africa.  

Some of my friends may assume it is because of the humiliation I suffered at the provincial gala event…  But it’s not.  

I feel that I’m not a good teacher.  

Yes I am very involved in the classroom administration , with management and in school development,  yet I am falling short in the one area that matters.  

I am failing my students.  No matter how hard I try, I cannot keep up good results in standardised tests.  

  • I have provided my learners with workbooks that is a summary of all the work the syllabus guidelines provide, yet they do not understand the core concepts of Life Science .  
  • I provide them with revision plans dividing work into small portions to study three times a week.  Yet they fail at the basic terminology tests.  
  • I work through old exam papers with them, showing them where the pitfalls are, yet they cannot remember basic instructions like “start each question on a new page”  –  even after five years in highschool! 
  • I guide my learners through the science Expo using the Scientific method –  yet they still don’t understand the difference between an aim and a Hypothesis.  

Is there anyone out there that can give me some guidelines on how to fix this?  Help will be appreciated!