EOY Revision of Year 8 - Science

Luca Cameron
Flashcards by Luca Cameron, updated more than 1 year ago
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End of year - Everything we did in year 8 - revision Topic List: respiration, nutrition & digestion, gas exchange, variation, periodic table, compounds & mixtures, atoms & elements, changing state, metals & non-metals, chemical reactions, rock cycle, heat transfer, waves, reflection & refraction, sight, colour, sound, hearing, energy. A LOT!!
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Question Answer
Respiration is a ----- reaction chemical
What is the word equation for respiration? glucose + oxygen --> carbon dioxide + water + ENERGY
Glucose and oxygen are the (reactants/products) as Carbon dioxide and water are the (reactants/products). reactants, product
There are 2 different types of respiration. What are they? Aerobic & Anaerobic
Describe both types of respiration Aerobic - uses air Anaerobic - without air
Which type of respiration is less efficient? How much energy does it release in comparison to the other? Anaerobic respiration is less efficient, so it releases less energy!
For humans, write the word equation for anaerobic respiration glucose --> lactic acid + ENERGY
To have a healthy diet, you need 5 nutrients as well as fibre & water. Name the 5 nutrients. 1) Carbs 2) Proteins 3) Lipids (fats and oils) 4) Vitamins 5) Minerals
In what kinds of food can you find lipids and carbs? Lipids --> butter/cooking oil Carbs --> bread/potatoes
The amount of energy you need each day depends on what? 1) body mass (weight) 2) level of activity
the extra energy that you take in from you diet (more food than you need) will be stored in your body as ___ fat
What can obesity lead to? Health problems like high blood pressure or heart disease
What are the 2 different steps to breaking down food? 1) mechanically 2) chemically
What is mechanical digestion? Chewing with your teeth
What is chemical digestion? Where your 8 bits of your digestive system break down food chemically with the help of different enzymes
What are the 8 different parts of our body that make up the digestive system (alimentary canal)? Name them in order 1) mouth 2) oesophagus 3) stomach 4) liver 5) pancreas 6) large intestine 7) small intestine 8) rectum (anus)
Which enzyme is contained in saliva and what does it do? amylase breaks down carbs
Which enzyme is found in the stomach and what does it do? protease enzymes break down proteins
Which enzyme is found in the liver and what does it do? Bile breaks down fats
Which enzymes does the pancreas make and what do each of them do? Protease digests protein Carbohydrase digests carbs Lipase digests lipids (fats)
What happens in the large intestine? The water is absorbed
What happens in the small intestine? food is absorbed through the gut wall into the blood, which then takes it around the body to wherever its needed
What do enzymes do? Break up the big molecules into smaller ones (e.g. to help it pass through the gut wall in the small intestine)
Where are the 'villi' in your body and what do they do? They're in your small intestine and they absorb food
Give 3 physical features that villi has 1) thin outer layer of cells (absorb) 2) good blood supply 3) large surface area for absorption
True of false: We have a lot of bacteria in the gut which is not good for us. FALSE! Yes we do have bacteria in our guts but they're actually really good for us!
What/How does natural bacteria in our gut produce/help us --produces enzymes --produce useful hormones --make useful vitamins (k) -- reduce possibility of harmful bacteria growing there
What are your lungs protected by? Your ribcage
What is the diaphragm and what does it do? It's a muscle that sits under the ribcage. It contracts and relaxes to help get the air in and out of your lungs
The air we breathe in goes through the -----. This splits into to parts called the -----. trachea, bronchus (pl. bronchi)
The bronchi split into smaller tubes called -----, they end at smaller air sacs in the lungs called -----. This is where gas exchange takes place bronchioles, alveoli
In the alveoli, how does gas exchange occur? The oxygen inhaled pass out the alveoli into the bloodstream, and the waste product (CO2) get transferred back into the alveoli to be exhaled 1123378e-9b66-46c2-8ead-3687a49e76f6.jpg (image/jpg)
Where does the oxygen that got inhaled, and passed into the bloodstream by the alveoli, go next? To cells in need of energy
From the bloodstream, ----- is passed out to the cells, and ----- is passed from the cells into the bloodstream. oxygen, carbon dioxide
When gases (O2, CO2) pass in and out of our bloodstream, this process is called ----- diffusion
What happens in diffusion? Where a substance moves from where there is a lot of it to where there is less of it
Give 3 reasons why our lungs are well adapted for gas exchange 1) They're moist 2) They have a good blood supply 3) The alveoli give the lungs a big inside surface area
When you breathe in, your diaphragm moves up or down? down
Name two things that can affect your gas exchange system Any of these three: --exercise --asthma --smoking
Most cells in your body have a nucleus. The nucleus contains -----. They are molecules made up of your DNA chromosomes
Human body cells have -- chromosomes, (-- pairs) but sperm and egg cells on carry -- chromosomes 46, (23), 23
The process by which genes are passed down from parents to their offspring is called ----- heredity
Who were the first 2 scientists to build a model DNA? In what year? Crick & Watson 1953
The variation within a species basically have the same genes. Any difference that you can see is called a ----- ----- characteristic feature
What are two different types of variation? Continuous and Discontinuous
Describe each type of variation and give two examples Continuous --> can vary over a range of values (e.g. height/weight/skin colour) Discontinuous --> can only take certain values (e.g. blood group/eye colour)
Use these four words to complete the sentence below: (melts, freezes, boils, condenses) A gas ----- to become a liquid. A liquid ----- to become a solid. A solid ---- to become a liquid. A liquid ----- to become a gas. condenses freezes melts boils
On a graph, when heating and cooling, what happens when the line is flat? its changing state
What is everything made up of? ATOMS! (if you got that wrong, then there is no hope.. ;p)
What's an element? A substance that only contains one type of atom.
What is it called when you have two or more atoms? A compound
How are compounds formed? Through chemical reactions
The atoms are ----- in a compound, but ----- in a mixture joined & not joined
The periodic table lists all the ----- ELEMENTS (not compounds!)
Who was the first person who invented the periodic table? Mendeleev
When two different elements combine, the end of the new name is usually "---" When three or more different elements combine (and one of them is oxygen), the end of the new name is usually "---" ide, ate
If two identical elements combine, does the name change? NO!
What's a pure substance? One type of element OR only one type of compound.
A pure substance can't be separated into anything simpler without a ----- reaction chemical
Mixtures are not ----- joined up - therefore you can ---- them very easily using physical methods chemically, separate
What do these 7 important words mean? -- solute -- solvent -- solution -- soluble -- insoluble -- saturated --solubility 'Solute' - the solid being dissolved 'Solvent' - the liquid its dissolving into 'Solution' - mixture of a solute and a solvent that doesn't separate out 'Soluble' - means it WILL dissolve 'Insoluble' - will NOT dissolve 'Saturated' - a solution that won't dissolve any more solute at that temp. 'Solubility' - measure of how much solute will disolve
Answer the question: 20g of salt + 100g of water = ___g solution 120
Solubility increases with ----- temperature
Name 4 ways in which mixtures can be separated 1) Filtration 2) Evaporation 3) Chromatography 4) Distillation
Give 5 statements about metals Choose either: - left side of periodic table - conduct electricity - conduct heat - strong and tough - shiny - sonorous (make sound) - malleable (easily shaped) - ductile - high melting and boiling points - high densities - make alloys with other metals - magnetic
Give 5 statements about Non-metals Choose either: - right of periodic table - poor conductors of electricity - poor conductors of heat - not strong or hardwearing - dull - brittle - low melting and boiling points - low densities - not magnetic
TRUE or FALSE: Before and after a chemical reaction, no mass is lost or gained TRUE
TRUE or FALSE: During a chemical reaction, new atoms are created FALSE: Atoms are not created or destroyed. The atoms from before the reaction are still there after, but bonds get broken and bonds get made as the atoms rearrange themselves!
Name two examples of chemical reactions 1) Combustion 2) Oxidation
What is combustion? Its BURNING! A fuel reacts with oxygen to release energy. For combustion, you need: -fuel -heat -oxygen
What is oxidation? The gain of oxygen! When a substance combines/reacts with oxygen. 'combustion' is an example of oxidation. Another example is rusting
What is thermal decomposition? When a substance breaks down into at least two other substances when heated
In an (endothermic/exothermic) reaction, heat is given out. In an (endothermic/exothermic) reaction, heat is taken in. exothermic endothermic
The earth has a -----, a ----- and a ----- crust, mantle & core
Choose either 'mantle, core & crust': We live on the earth's -----, and below it lies the -----, which is above the earth's ----- crust mantle core
As you go deeper into the mantle, the temperature (increases/decreases) increases
What is the earth's core made up of? Iron and nickel
TRUE or FALSE: The earth's crust contains vitamins FALSE! It contains minerals!
Use these 4 words to complete the sentence below (elements, rocks, minerals & compounds) "----- & ----- make up ----- and these make up -----" elements and compounds make up minerals and these make up rocks
The earth's surface is made up of ----- ----- (hint: take part in earthquakes) tectonic plates
What are the three different types of rocks? 1) Igneous 2) Sedimentary 3) Metamorphic
da94a773-1326-49f9-99b5-0c049df1764c.gif (image/gif) 1) Sedimentary 2) Metamorphic 3) Intrusive Igneous 4) Extrusive igneous
What are the two different types of igneous rock and what are different about them? Intrusive --> cool quickly above ground Extrusive --> Cool slowly under ground & eventually get exposed when rocks above them wear away
How do sedimentary rocks form? And what can you find in them? Layers of sediment laid down for millions of years make a solid, and fossils ca be found here
How do metamorphic rocks form? As the sedimentary rocks get closer to the magma, it heats rapidly and pressure increases, which forms metamorphic rocks!
Give one example of each type of rock sedimentary - limestone, chalk, sandstone metamorphic - marble, slate intrusive igneous - granite extrusive igneous - basalt
a00642cd-aa52-4a13-8d52-205c9c766482.jpg (image/jpg) just study that photo
What are the three types of heat transfer? 1) CONDUCTION 2) CONVECTION 3) RADIATION
Explain radiation - doesn't need particles to travel - travels in invisible waves - hotter the object, the more radiation it gives off - the cooler the object, the more it absorbs - can travel through vacuum (space) - used for sun to heat earth!
explain conduction - heat spreads through particles by vibrations - need particles, so it can't travel through a vacuum (space) - when particles bump into each other to spread the heat
explain convection - only happens in liquids - a convection current - gets heated, rises, and slowly makes it way back to heat source again (boiling water) - can happen in gases but its harder and slower (e.g. a fire/smoke around a room) - can not happen in solids!
TRUE OR FALSE: Physical changes do involve a change in mass FALSE: they don't involve a change in mass
Whats different between physical and chemical changes/reactions? Physical - no reactions chemical - is a reaction
Name 4 types of physical changes melting, evaporating, condensing, freezing
What is it called when a substance goes from a solid STRAIGHT to a gas? sublimation
TRUE or FALSE: Light waves don't need particles to travel through TRUE
What travels faster? Light or sound? LIGHT! never mix that up ;)
How far is the sun from the earth? 150,000,000 km
How long does it take for light from the sun to travel to the earth? 8.3 minutes
When a ray of light hits a mirror at an angle, it ----- off the other side reflects
What is angle i called? What is angle r called? What is the line in the middle called? What is this diagram showing? Are angles i & r equal? c59c271f-9839-4e2b-bcc3-61122aaa5513.gif (image/gif) - angle of incidence - angle of reflection - normal line - reflection - yes
The normal line is at a -- degree angle from the mirror 90°
What is refraction? When light bends as it crosses a boundary
Light can go through a transparent object, but not through an ----- one opaque
The substance that light (or another wave e.g. sound) travels through is called a ----- medium
When light goes from a less dense medium to a more dense medium, the light bends (towards/away from) the normal line. Give an example towards e.g. air to glass
When light goes from a more dense medium to a less dense medium, the light bends (towards/away from) the normal line. Give an example away e.g. glass to air
At what angle will the light pass straight through the medium without refraction? 90°
The ray of light entering the medium is known as the ----- ray incident ray
the ray which exits the medium is known as the ----- ray refracted ray
How do we see? When luminous objects produce light (e.g. a lamp) it reflects off non-luminous objects (e.g. people). Some of this reflected light then goes into our eyes.
What type of camera is similar to our eye? The pinhole camera
What type of lens do we have in our eye? Convex lens
What does our convex lens do? It causes the light to converge (move together) into focus
What does the iris do (in our eye)? It controls how much light enters our eye
Where are the images formed on the retina
Name all the colours in white light (in order) red orange yellow green blue indigo violet
red is bent the (most/least) as violet is bent the (most/least) when getting dispersed red = least violet = most
Define dispersed when white light gets split up into different colours through a prism (e.g. raindrop / glass block)
What's the proper name for a rainbow? spectrum
Why do all the colours get dispersed at different angles? they have different wavelengths and frequencies which portrays how fast each wave is going, so violet might hit the prism, as it travels faster, so therefore it gets dispersed before the others
How does a red filter work? It only lets red pass through it, therefore absorbing all other colours
Why are blue jeans blue? It absorbs all colours but blue, which gets reflected. So we see that reflected colour!
Does sound pass through a solid, liquid or gas the quickest? Why? solid because the more particles, the faster a sound wave travels
What's frequency and what is amplitude? frequency = pitch amplitude = loudness
As sound waves, how is the frequency shown and how is the amplitude shown? amplitude = height of sound wave frequency = length of sound wave
how is frequency measured? hertz (Hz)
How is amplitude measured Decibels dB
e05421df-b5b1-4379-8c1f-8a7a97897ad7.png (image/png) right: (highest) = cornea (middle) = pupil (lowest) = iris middle: (middle right) = lens left: (highest) = optic nerve (lowest) = retina
Name the parts in the ear - in order for how we hear things - sound waves enter the pinna - travels through ear canal - vibrated ear drum - amplifies ossicles - travels through small window to cochlea - little hairs in cochlea send message to brain through auditory nerve
What's an ultrasound? all sounds that have a higher pitch than the normal auditory range of humans (so anything over 20,000 Hz)
magnets are surrounded by ----- magnetic fields
bar magnet have two -----. What are they called? North pole and south pole
From which to which pole to magnetic field lines always point? North to south poles
How can you see these magnetic field lines? By using a plotting compass or iron fillings
opposite poles -----, like poles ----- attract - repel
Which planet has a magnetic field? THE EARTH!!!
What's an electromagnet? a core with wire wrapped around, connected to a current which gives off magnetic field lines
what's the cool thing about electromagnets that normal magnets can't do? they can be switched on and off
name three ways in which you can increase the strength of an electromagnet? 1) more current in the wire 2) more turns of wire 3) a soft iron core
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