Grade 8-Science Review

Flashcards generated from lecture notes to help a student review for an exam.

What are the different layers in an ocean and their organisms?

Different organisms live at different ocean levels.

Where is greater biodiversity found: ocean or lake?

Lakes have more biodiversity because of nearby land habitats.

How do plants and animals survive in water?

Plants and animals adapt to temperature, light, pressure, salinity and water movement.

What is distillation?

Boiling water into gas and then condensing it back.

What is reverse osmosis?

Forcing water through a filter with tiny pores.

Why are algae blooms bad?

Too many nutrients in water cause algae explosions that release toxins and block sunlight.

What is WHMIS?

Workplace Hazardous Materials Information System

Does each state have a definite shape or volume?

Solid: definite shape and volume. Liquid: definite volume. Gas: no definite shape or volume.

How are particles arranged in each state of matter?

Solid: particles fixed, vibrate. Liquid: particles slide. Gas: particles spread apart.

What are the five points of the particle model?

All matter has particles; particles move; particles attract; particles have spaces; temperature affects speed.

How does a liquid become a gas?

Liquid particles move faster until they become gaseous.

How do machines help?

Machines help us use energy more effectively.

What is work?

Work is force acting on an object to move it.

How is work calculated?

Work = Force x Distance

Why do machines make work easier?

Machines trade force for distance, making work easier.

What is mechanical advantage?

The amount a machine multiplies force.

What is speed ratio?

Input distance divided by output distance.

How do you calculate efficiency?

(Mechanical Advantage / Speed Ratio) x 100

How does friction affect machines?

Friction requires more force, affecting efficiency.

How is pressure calculated?

Pressure = Force / Area

What are the two main types of water?

Saltwater and freshwater.

How do glaciers affect the Earth?

Glaciers carved lakes and left rocks.

What forms does fresh water exist in?

Ice, liquid, and vapor.

What is a watershed?

Land that drains into one lake or river.

What are the lake layers and their organisms?

Organisms live in different lake layers.

Define transparent, translucent, and opaque.

Transparent: transmits light (glass). Translucent: some light (tissue paper). Opaque: no light (metal).

What are the four principles of light?

Light travels straight, reflects, bends, and is energy.

What is the Law of Reflection?

Light bounces off at the same angle it hits.

What is regular vs. diffuse reflection?

Regular: predictable reflection. Diffuse: light scatters.

What is refraction?

Light bends when it changes mediums.

Does light bend toward or away when going from more dense to less dense?

Away from the normal.

Does light bend toward or away when going from less dense to more dense?

Toward the normal.

What are concave and convex lenses?

Convex: thick middle, focuses light. Concave: thin middle, diverges light.

How does light behave in each lens?

Convex: focuses then flips light. Concave: diverges light.

What do the retina, ciliary muscles, lens, rods, cones, cornea, pupil, iris do?

Parts of the eye and their functions.

How does the eye form an image?

Eye bends light, brain flips image.

What is a camera eye vs. a compound eye?

Camera eye: lens, most animals. Compound eye: many units, insects.

What is a reflecting vs. refracting telescope?

Reflecting: mirrors. Refracting: lenses.

How did microscopes and telescopes lead to new knowledge?

Microscopes and telescopes helped discover new things.

How do simple machines work?

Simple machine descriptions.

What are homogeneous and heterogeneous mixtures?

Homogeneous: one set of properties. Heterogeneous: multiple visible materials.

What is a suspension, colloid, and emulsion?

Suspension: particles float. Colloid: particles evenly spread. Emulsion: colloid of liquids.

What is a solute and solvent?

Solute dissolves. Solvent does the dissolving.

What affects the rate of dissolving?

Temperature, size, stirring, and type of substance.

What are saturated, unsaturated, and supersaturated solutions?

Saturated: max solute. Unsaturated: more solute can dissolve. Supersaturated: more than max.

What is viscosity?

Thickness of a fluid.

What is flow rate?

Amount of fluid past an area in time.

How are flow rate and viscosity related?

Flow rate measures viscosity.

What happens when pouring different liquids down a ramp?

Different fluids flow at different rates due to viscosity.

How does temperature affect viscosity?

Heating decreases viscosity, cooling increases it.

What is density?

Mass per volume.

How do you calculate density?

Density = Mass / Volume

Define buoyancy, neutral buoyancy, and buoyant force.

Buoyancy: ability to float. Neutral: gravity = buoyancy. Buoyant Force: upward force.

Why do steel ships float?

Ships have air, making average density lower than water.

What is Archimedes' principle?

Object displaces liquid equal to its volume.

How do we calculate pressure?

Pressure = Force / Area

What is Pascal's Law?

Enclosed fluid transmits pressure equally.

What is compression?

Decreasing volume with pressure. Only gases compress.

What is the difference between hydraulic and pneumatic systems?

Hydraulic: liquids, closed. Pneumatic: gases, open.

What is slurry technology?

Oil-sand slurry pumped through pipelines.

What are the six characteristics of living things?

Cells, energy, growth, response, reproduction, adaptation.

What are adaptations?

Mutation that helps survival.

What do the nucleus, mitochondria, cell membrane, vacuoles, cytoplasm. cell wall, and chloroplasts do?

Cell organelle functions.

What is the difference between plant and animal cells?

Plant cells have cell wall and chloroplasts.

What are diffusion and osmosis?

Diffusion: movement from high to low concentration. Osmosis: water diffusion. Osmosis is for water.

What are the different specialized cells?

Muscle, nerve, epithelial, connective cells and their functions.

What are unicellular and multicellular organisms?

Unicellular: one cell. Multicellular: many cells.

What are the parts and functions of the five body systems?

Body systems and their functions.

How do the different body systems work together? Give specific examples.

The circulatory system works with every other system, as it acts as the transport system for all nutrients, oxygen, carbon dioxide, waste products and other substances. The respiratory system oxygenates the blood, which keeps the body alive. The digestive system provides the nutrition and removes solid waste needed to keep the body alive. The excretory system filters out the waste products created by all of the other systems. The nervous system controls every other system throughout the body.