BIPS Y8

T1 SCIENCE REVISION

Name the Scientific Methods in order:

- Purpose
- Research
- Hypothesis
- Experiment
- Analysis
- Conclusion

What is a Scientific Method?

A way in which scientists gather information and answer questions.

What is the goal of science?

To investigate and understand the natural world, explain events and use those explanations to make useful predictions.

What is diffusion?

The random movements of particles from a high concentration to a low concentration.

Where does diffusion happen the fastest? Why?

In gases, because the particles are farthest apart from each other and can travel long distances without hitting other particles.

Examples of some substances that move by diffusion:

Oxygen, perfume, etc.

Diffusion of ____ into the bloodstream.

Oxygen

Diffusion of ____ out of the bloodstream.

Carbon Dioxide

Formula for Aerobic respiration:

Glucose + Oxygen -> Carbon Dioxide + Water + Energy

Formula for Anaerobic respiration:

Glucose -> Lactic Acid + Energy

What is Aerobic respiration?

A chemical reaction for respiration WITH oxygen.

What is Anaerobic respiration?

A chemical reaction for respiration WITHOUT oxygen.

What is Mitochondria?

An organelle that performs the process of aerobic respiration.

Mitochondria's structures:

- 2 membranes:
~ Smooth outer membrane
~ Highly folded inner membrane
- Cristae
- Fluid-filled space between the 2 membranes

Mitochondria's functions:

- Makes ATP energy from cellular respirations
~ Sugar + Oxygen -> ATP
~ Fuels the work of life

Note:

Mitochondria is the powerhouse of the cell and is in BOTH plant cells and animal cells.

The Respiratory System:

A group of specialized organs dedicated to the exchange of oxygen and carbon dioxide.

Organs of the Respiratory System in order:

- Nasal Cavity
- Pharynx
- Larynx
- Trachea
- Bronchi
- Lungs
- Alveoli

The Nasal Cavity's uses:

Air enters the nose through two nostrils and reaches the nasal cavity. Here, the air is warmed and filtered. The hair present in the nostrils stop the dust or germs from entering the human respiratory system.

Pharynx's uses:

Muscular region connecting the nasal and oral cavities with the help of the Larynx and Esophagus.

Larynx's uses:

The Larynx is the part of the respiratory tract which contains the vocal cords. It has functions in;
~ Respiration (breathing)
~ Phonation (voice production)
~ Deglutition (swallowing)

Trachea (windpipe)'s uses:

- The tube that leads to the lungs from the pharynx.
- Contains rings of cartilage.
- Lined with ciliated mucous membrane.

Bronchi's uses:

The two large that connects the trachea to the lungs.

Lungs' uses:

- The lungs are two large sponge-like organs that are located in the chest.
- The lungs are divided into sections called lobes:
~ The left lung has 2 lobes.
~ The right lung has 3 lobes.
- The left lung is smaller than the right lung due to the position of the heart.

Alveoli's uses:

- Site of gas exchange.
- The bronchioles end in a cluster of minute air sacs called the alveoli.

Diaphragm's uses:

The muscle below the lungs that controls breathing.
- Contracts during Inhalation
- Relaxes during Exhalation
- Major muscle of breathing

Intercostal muscle's uses:

Intercostal muscles are found between each of your ribs and provide support to your upper body and assist in breathing.

Respiratory tract function:

Inhale air into the lungs.

Respiratory organs function:

Exchange of Oxygen and Carbon Dioxide in the blood.

What 4 stages can gas exchange in humans be divided into?

- Breathing
- External Respiration
- Internal Respiration
- Oxygen and Carbon Dioxide transport

Gas Exchange in humans:

- Occurs in the alveoli
- Oxygen diffuses into the blood
- Carbon Dioxide diffuses into the lungs

Differences between breathing and respiration:

Diagram of breathing in and breathing out:

What is a mixture?

A mixture is made up of 2 or more types of atoms that are NOT chemically combined together.

What are the 2 major types of mixtures?

- Heterogeneous; meaning different
- Homogeneous; meaning same

What are the characteristics of mixtures?

- Variable composition
- Components retain their characteristic properties.
- May be separated into pure substances by physical methods.
- Mixtures of different compositions may have widely different properties.

Note:

What are Pure Substances?

Elements or compounds that consists of only one type of particle, e.g., Oxygen, honey, etc.

What are the characteristics of Pure Substances?

- Pure Substances cannot be separated by physical means.
~ Elements: Cannot be chemically separated, listed in the periodic table.
~ Compounds: Can be chemically separated, made up of elements.

Pure Substances' uses:

In the pharmaceutical industry, medicine must be tested for purity before they are sold. Impurities in drugs and food may produce undesirable side effects.

How to determine the purity of a substance?

- Checking the melting point of a substance
- Checking the boiling point of a substance
- Performing Chromatography

What are the factors affecting diffusion?

- Temperature
- Surface Area
- Concentration
- Size of particles
- Diffusion medium

What is Pressure?

Pressure is the force per unit area that one object exerts on another.

Pressure depends on __(a)__ over which __(b)__ is distributed

(a) area
(b) force

What are the characteristics of pressure in a liquid?

- Acts equally in all directions.
- The bottom of a boat is pushed upward by water pressure.
- Pressure acts upward when pushing a beach ball under water.

How does pressure vary?

- When we're on land, the pressure inside our bodies is the same as the pressure of the air around us.
- However, when people go diving, there is extra pressure from the water above. The greater the depth, the higher the pressure.
- When you're deep in the water, the pressure results from the weight of water pressing down on you from above.

What are the properties of Gases?

- Gases have mass.
- Gases take shape and volume of all containers.
- Gases are compressible.
- Gases easily move through each other. (e.g., perfume)
- Gases exert pressure.

What are the characteristics of Pressure in Gases?

- Gases exert pressure on their surroundings.
~ E.g., A balloon filled with air. Air pushes against the elastic sides if the balloon and keeps it firm.
- Gas pressure is the name given to the force exerted by gas particles colliding with the wall of their container.
~ A car tyre contains gas under pressure.

Show a diagram showing gaseous particles in a container to represent pressure in gases: (Arrows can be added to show the force exerted by the particles on the walls of the container.)

What are the units for pressure, force, and area?

Pressure = Pa (Pascal)
Force = N (Newtons)
Area = m² (square meter)

Write Pressure, Force, and Area in equation form:

Pressure = Force ÷ Area
Force = Pressure x Area
Area = Force ÷ Pressure

Note:

1 Pascal is the same as 1 Newton per square meter.

If a material dissolves, it is ____.

Soluble

If a material doesn't dissolve, it is ____.

Insoluble

What is a solute?

The solid that dissolves.

What is a solvent?

The liquid that the solute dissolves in.

What is a solution?

The mixture of a solute and a solvent.

What is solubility in water?

- Water solubility is a measure of the amount of chemical
substance that can dissolve in water at a specific temperature.
- The unit of solubility is generally in mg/L (milligrams per liter) or ppm (parts per million).

What are the different types of solutions?

- Saturated Solution:
~ Holds the maximum amount of solute.
- Unsaturated Solution:
~ Holds less than the maximum amount of solute.
- Supersaturated Solution:
~ Holds more than the maximum amount of solute.

What is solubility?

The amount of solute that dissolves in a solvent.

What are the factors affecting solubility?

- Temperature
~ As temperature increases, the solubility of solids in liquids increases.
~ As temperature increases, the solubility of gases in liquids decreases.

What solubility does pressure affect?

- Pressure only affects the solubility of gases.
~ As air pressure increases, solubility of a gas increases.

Solubility of a solute in a solvent purely depends on the ____ of both solute and solvent.

nature

What is the meaning of chromo and graphy?

Chromo - meaning colour
Graphy - meaning the representation of something on paper.

What is chromatography?

- Chromatography is a technique for separating mixtures into their components in order to analyse, purify and/or quantify the mixture of components.

What is a chromatogram?

- The pattern left by the colours is called chromatogram.
- Each colour is made of different ink, meaning they will have their own chromatogram.

Label this diagram:

Light travels in _(a)_ lines.

Light travels much _(b)_ than sound.

We see things because they _(c)_ light into our eyes.

Shadows are formed when light is _(d)_ by an object.

(a) Straight

(b) Faster

(c) Reflect

(d) Blocked

What is light reflection?