Grade 8 Science Final Exam Review

Unit 1

Mix and Flow of Matter

What are the characteristics of pure substances

A pure substance is made up of one type of matter. It has it's own boiling point, melting point, density, and viscosity.

How are homogeneous solutions made

Homogeneous solutions are when two substances are mixed but it looks like only one substance

Name the mixtures that look like solutions and explain how they could be separated

A homogeneous mixture looks like a solution. They can be determined by doing to test such as chromatography.

How to remove salt from sea water

Reverse osmosis and distillation.

What is viscosity?

Resistance to flowing

How temperature affects viscosity of liquid gas

The internal resistance of friction between the particles of the substance determine the viscosity of that substance. The more friction the viscous a substance is. The higher the viscosity of a substances he slower it is. Increasing temperature, lowers viscosity (makes it thinner and easier it flows). Decreasing the temperature increases viscosity (making it thicker and harder to flow).

Density

Mass per unit of volume: calculated by dividing the mass of the substance by the volume.

Why do heavy objects sink or float in a fluid

Based on their density, and how much water is being pushed away

What is average density and why is it important

Density= mass/volume, density of a whole area

Benefits of average density

It allows for things that have a higher density to float.

Compressibility of liquids and gasses

Gases can be so pressed more than liquids can because the particles of a gas are further away than the ones in liquid

Unit 2

Cells and systems

What is the name of all structures inside of Cells.

Organelles

What are two structures that are found in plant cells and not animal cells and what is their functions.

Cell wall- it provides strength and support to plants and is the "frame" of the plant.

Chloroplasts- found in the green part of a plant and carries out photosynthesis. They are the "solar panel" of the cell.

What is the cell theory

1. All living organisms are composed of one or more cells

2. The cell is the most basic unit of life

3. All cells come from pre-existing or living cells

What is the function of the white blood cell

The white blood cell is specialized in fighting infections

Order of multi celled organisms

Cells create tissue

Tissue creates organs

Organs create systems

Systems create a human body

Cells, tissue, organs, systems

Order of digestion for a sandwich you eat

It starts by entering the mouth, then it travels through the esophagus to the stomach, it then breaks down in the acids of the stomach and moves through the small intestine to the large intestine, it then stores in the rectum and leaves the body through the anus.

What is the function of the stomach, small intestine, and large intestine.

They absorb nutrients. The villi are the small things in the small intestine that absorb the nutrients.

What is the central part of the digestive system?

To break down food into small pieces so they can be absorbed and transported.

What is the central part of the respiratory system?

To transport oxygen from the outside air to the blood, and to transport carbon dioxide to the outside air using blood and the lungs.

What is the central part of the nervous system?

Coordinating and controlling the actions of all organs and organ systems. The system detects processes and responds to changes in the internal and external environments.

What is the central part of the circulatory system?

To transport oxygen food and other substances throughout the body, transports some wastes to other organs for elimination it defends the body against diseases and connects all other organ systems.

What is the central part of the excretory system?

To remove chemical and gas waste from our body.

Who invented the first microscope?

Anton van Leeuwenhoek.

Parts of the cell

Organelles

Vacuole

Organelle that stores water substances required by the cell.

Cytoplasm

The contents in the cell on the inside of the membrane that stores nutrients that the cell needs, it is the main inside of the cell.

Cell membrane

Thin structure on the outside of the cell that encloses all the contents of the plant and animal cell. They have tiny openings that allow some substances to pass through.

Mitochondria

Organelle that converts energy that the cell receives into a form that it can use

Cell wall

Outer covering of the plant cell that provides strength and support

Chloroplasts

Organelle in the plant cell that converts sunlight into energy/food by using photosynthesis.

Nucleus

Organelle that directs all activities in a cell. Acts as the brain of the cell.

Unit 3

Light and optical systems

Incandescent

A form of artificial light. It uses electrical energy to heats thin wire thread that grows whit hot

Bioluminescent

The ability of certain organisms to produce light by chemical reactions

Chemiluminescent

The emission of light resulting from a chemical reaction. A glow stick is and example of this

Florescent

Form of artificial light. It uses ultraviolet light waves to make coating inside an opaque tube glow white.

Opaque

Describes materials that do not allow light to pass through for example wood, metal.

Translucent

Describes materials to allow some light to pass through

Transparent

Materials to allow all light to pass throigh

Law of reflection

Angle of incidence of a wave hitting a surface equals to angle of reflection

What is reflection

Convex lenses

Concave lenses

What is light and some properties

Why does refraction happen and how does it work

Bending of light through concave and convex lenses

Best surfaces for reflecting and and absorbing light

Types of waves

Gamma

X-ray

Ultraviolet

Radil

Microwave

Infared