• Wrong document? Swap it for free
  • Written by students who passed
  • Immediately available after payment
  • Read online or as PDF
Sell
Where do you study
Your language
Document preview thumbnail
Preview 3 out of 20 pages
Summary

Summary Biology Notes - Grade 9 IEB

Document preview thumbnail
Preview 3 out of 20 pages

Biology theory notes for Grade 9 IEB. Contains basic scientific skills like magnification formulas as well as colourful and typed notes including diagrams especially for various systems.

Content preview

,SCIENCE SKILLS AND PROCESSES
SCIENTIFIC METHOD


1. Aim: To investigate … the relationship between ( independent variable ) and the ( dependant variable )
2. Hypothesis: Short statement with your guess ( no “I” )
3. Method: Detailed instructions
4. Result: Represented in graph or table
5. Conclusion: summarise main findings, refer to hypothesis being true or not


Independent Variable: Dependant Variable: Controlled Variable: Control Group:
What you change What is being measured What stays the same Nothing is changed



LINE AND BAR GRAPHS


Bar graphs show discontinuous data while Line graphs show continuous data. The line graph also has a plotted
dots that are then joined with a solid line along with a key if 2 lines are involved, but in a bar graph the bars
must be equal width and spacing. But here are some similarities:


- an informative heading including the independent and dependant variables written above the graph and
underlined.
- the independent variable labeled on x-axis ( horizontal ) and dependant variable on y-axis ( vertical ).
- a suitable scale for both y and x axis.
- heading: a table or graph showing the relationship between …


TABLES

NOTE: when working with
- Informative heading with dependant and independent variables.
the scale bar convert mm to
- Independent variable in right column and Dependant variable in left column.
um
- Column heading includes name and units ( no units in the table itself )


FORMULAS:


Calculating Magnification:
Magnification = Draw Size mm
Calculating actual size of magnified specimen:
Size of specimen = drawn size ( mm -> um
I ) X 1000
I
magnification

A M
Actual Size um


=x X 1000 =
ans = um

Calculating Actual Size of Magnified Specimen using Scale Bar:
Actual Size = size on diagram mm * no .
on scale bar
measured length of scale bar mm


= um x 10 x 1 000 x 1 000



Centimeter Millimeter Micrometer Nanometer
( cm ) ( mm ) ( um ) ( nm )



- 10
·




-: 1 000 -: 1 000

, THE RESPIRATORY SYSTEM


Function And Processes


- Provide the body with oxygen and removes the carbon dioxide from the body. The 3 main processes that must
occur:


Breathing ( mechanical )
- Inhaling ( oxygen intake ) and exhaling ( removing carbon dioxide )
- Inhaling: intercostal muscles ( between ribs ) contracts and lifts the ribs up while the diaphragm contracts and
flattens. Increases the volume of the chest cavity. Lungs fill with air and alveoli and increase as the elasticity
reduces and volume in lung increases. Decrease in air pressure in lungs so that air pressure in chest and lungs
become equal.
- Exhalation: intercostal muscles relax and diaphragm relax and moves up. This decreases the volume of the
chest cavity. Elasticity increases and causes volume of lungs to decrease. Reduction of chest cavity causes an
increase in air pressure pushing air out of the lungs through the airways. Reduced air pressure in the lungs
allows the air pressure in the chest cavity and lungs to be equal.

Inhaling Exhaling




Gaseous Exchange
i
Lungs ( external )
- Exchange of oxygen and carbon through diffusion
- Oxygen diffuses from alveoli ( high concentration ) to blood ( low concentration )
- Carbon diffuses from blood ( high concentration ) into alveoli ( low concentration )
- Diffusion: movement of gas molecules from high concentration to a low concentration
- Happens between alveoli and surrounding capillaries



Blood Capillaries Lung Body Tissue Blood Capillaries



. (I
·
O
CO



O CO

Alveolus


External Gaseous Exchange Internal Gaseous Exchange

Document information

Schooljaar
200
Uploaded on
October 3, 2025
Number of pages
20
Written in
2020/2021
Type
Summary
$11.16

Wrong document? Swap it for free Within 14 days of purchase and before downloading, you can choose a different document. You can simply spend the amount again.
Written by students who passed
Immediately available after payment
Read online or as PDF

Seller avatar
Reputation scores are based on the amount of documents a seller has sold for a fee and the reviews they have received for those documents. There are three levels: Bronze, Silver and Gold. The better the reputation, the more your can rely on the quality of the sellers work.
catarinacamacho
5.0
(1)
Sold
15
Followers
0
Items
26
Last sold
3 days ago




Why students choose Stuvia

Created by fellow students, verified by reviews

Quality you can trust: written by students who passed their tests and reviewed by others who've used these notes.

Didn't get what you expected? Choose another document

No worries! You can instantly pick a different document that better fits what you're looking for.

Pay as you like, start learning right away

No subscription, no commitments. Pay the way you're used to via credit card and download your PDF document instantly.

Student with book image

“Bought, downloaded, and aced it. It really can be that simple.”

Alisha Student

Working on your references?

Create accurate citations in APA, MLA and Harvard with our free citation generator.

Working on your references?

Frequently asked questions