Science (Entire Yr7) Flashcards
Introduction to science, particle theory, forces and speed, genetics and reproduction, acids and alkalis, energy and our planet
When lighting a Bunsen burner, which position should my air hole be in?
Closed
If my Bunsen burner air hole is closed what kind of flame will I have?
Safety flame
If my Bunsen burner air hole is open what kind of flame will I have?
Roaring
If my Bunsen burner air hole is half-open, half-closed what kind of flame will I have?
Normal blue
For heating solids, which Bunsen burner flame should I use?
Roaring
For gently heating, which Bunsen burner flame should I use?
Normal blue
Why should you not heat things using the safety flame?
They become sooty (carbon deposits)
The variable we change is known as….
Independent variable
Which axis on a graph is the independent variable normally plotted on?
X-axis
The variable we measure is known as…
Dependent variable
What kind of numeric data can only have certain values e.g. shoe size?
Discrete data
What kind of data is numeric and can have any value within a range e.g. height?
Continuous data
What kind of data could be a word rather than numeric value?
Categoric data
True/False - a line of best fit must be a straight line?
False - the shape depends on the relationship between variables.
True/False - a line of best fit should go from point to point
False - the line should be smooth. It should go through as many points as possible. There should be an equal number of points above and below the line.
Put these structures in order from largest to smallest -
* Cell
* Organ
* Tissue
* Organism
* System
Organism, System, Organ, Tissue, Cell
Which system transports nutrients, oxygen, hormones, waste products?
Circulatory
What is the purpose of the digestive system?
Breaks down food for absorption.
Which two systems are responsible for movement of the body?
Muscular and skeletal
What is the function of the endocrine system?
Produce and release hormones
Which system is responsible for the production of offspring?
Reproductive
What is the purpose of the nervous system?
Control and communication within the body
Which system is reposible for the removal of waste products
Excretory
What processes are associated with the respiratory system
Inhalation, exhalation, gas exchange
Name the 4 types of tissue found in animals
Muscle, connective, nervous, epithelia
Which part of a microscope is used to magnify an image?
Lens
Onto which part of the microscope do you place your slide?
Stage
Which 7 processes are often used to characterise something as living
Movement Respiration Sense Growth Reproduce Excrete Nutrition (MRS GREN)
Which feature do all living organisms share?
They are made of cells
What is the very thin permeable layer of a cell that controls what enters and leaves the cell?
Cell membrane
Which part of the cell contains DNA and controls cellular activities
Nucleus
Where do respiration (energy release from food) take place in the cell?
Mitochondria
Where do most chemical reactions occur in the cell?
Cytoplasm
Which features do you find in a plant cell, but not an animal cell?
Cell wall, vacuole, chloroplasts
Which part of plant cell is filled with cell sap?
Vacuole
What green pigment do chloroplasts contain?
Chlorophyll
Which state/s of matter can be compressed?
Gas only
Which state/s of matter flow
Liquids and gases
Which state/s of matter have a fixed volume?
Solids and liquids
Describe the arrangement of particles in a solid
Regular. Particles are touching
Describe the arrangement of particles in a liquid
Random. Particles are touching
Describe the arrangement of particles in a gas
Random. Particles are far apart
Describe the movement of particles in a solid
Vibrate about a fixed position
Describe the movement of particles in a liquid
Move around each other
Describe the movement of particles in a gas
Move quickly in all directions
Name the changes of state
Melting (solid -> liquid)
Evaporating (liquid -> gas)
Sublimating (solid -> gas)
Condensing (gas -> liquid)
Freezing (liquid -> solid)
Deposition (gas -> solid)
What is the melting point of water?
0 degrees celsius
What is the freezing point of water?
0 degrees celsius
How do the melting and freezing points of a substance compare?
They are the same
What is the boiling point of water?
100 degrees celsius
What causes pressure in a gas?
Gas particles colliding with the wall of their container
What happens to the pressure of the gas when we increase the temperature?
The pressure increases
Name the force between two surfaces sliding over one another, that causes them to heat up and wear away.
Friction
Name the force that pulls objects towards the centre of the Earth
Weight
Name the force acting against any object that is moving through the Earth’s atmosphere.
Air resistance/drag
Name the force pushing upwards on an object flying in the air.
Lift
Name the force pushing upwards on an object in a fluid.
Upthrust
Which force is a push caused by an engine (e.g. aircraft jet engine)?
Thrust
What is the unit of force?
newton, N
What instrument can we use to measure force in a lab?
newtonmeter
If forces on an object are not balanced what do we have?
A resultant force
If there is a resultant force on an object, what will happen?
Object will accelerate or decelerate
Describe the motion of the car
Stationary
Describe the motion of the car
Accelerating
Describe the motion of the car
Decelerating
Describe the motion of the car
Moving at constant speed
Name the forces acting on the car
Up - normal contact force, Down - weight, forward - friction (look back to your notes if you are unsure why), Back - air resistance/drag
What is the unit of weight?
newton, N
what is the unit of mass?
kilogram, kg
What is the formula that links mass and weight
weight = mass x gravitational field strength
What is the Earth’s gravitational field strength?
10 N/kg (make sure you get the unit right!)
What will happen to my mass if I go to the Moon?
stays the same
What will happen to my weight if I go to the Moon?
It will change (decrease - the Moon has a smaller mass and radius that the Earth so the gravitational field strength is lower than on Earth)
Describe the forces acting on a floating object
Weight = upthrust. These two forces are balanced. There is no resultant force
For an object in a fluid, if weight > upthrust, what will happen?
The object will sink
What causes upthrust?
There is a higher pressure at the bottom of the object than the top.
List 2 characteristics of a streamlined shape
Rounded front
Slowly tapering tail
Smooth shape with no projections
Name two ways to reduce resistive forces
Streamlining
Lubrication (reduces friction between moving parts)
How do we calculate speed
speed = distance / time
If you know the speed of an object and time taken to travel a certain distance, how can you calculate distance?
distance = speed x time
If you know the distance an object travelled and the speed it travelled at, how can you calculate the time it took?
time = distance / speed
The point a lever rotates about is known as….
Pivot
In a lever, the distance between the pivot and where the force is applied is known as…
lever arm
If I want to increase the turning effect of a lever, what 2 things could I change?
Increase the force applied
Increase the length of the lever arm (i.e. distance from where the force is applied to the pivot)
What is another word for turning effect?
moment
What name is given to a type of joint that moves backwards and forwards (e.g. a knee)
Hinge
What name is given to a type of joint that allows movement in a circle (e.g. a shoulder)
ball and socket
What name is given to a type of joint that allows movement around an axis (e.g. an ankle)
pivot
What is a pair of muscles that work in opposition to each other called?
antagonistic pair
What happens to the shape of a muscle when it contracts?
It gets shorter and fatter
What happens to the shape of a muscle when it relaxes?
It gets longer and thinner
What links bone to bone?
Ligament
What links bone to muscle?
Tendons
Why do we have fluid in our joints
To reduce friction between bones
The differences in characteristics between individuals of the samespeciesis known as….
Variation
What type of variation is passed on from parents to offspring, via genes during reproduction
Genetic
Variation which is the result of differences in the surroundings, or what an individual does.
Environmental
Give three examples of genetic variation
blood group, natural skin colour and natural eye colour, free or attached earlobes (there are more - check your Science booklet for examples)
Give three examples of environmental variation
Scars, tattoos, hair length (there are more - check your Science booklet for examples)
How do you know blood group is a genetic (inherited) and not environmental characteristic?
You are born with a particular blood group
It cannot change during your life
Your lifestyle does not affect your blood group
In which part of the cell is genetic information found?
Nucleus
How many pairs of chromosomes do (most) human cells contain
23
What are chromosomes made of?
DNA (a long molecule)
A short section of DNA that codes for specific features is known as what?
Gene
How do we describe the structure of DNA?
Double helix
How many versions of each gene do we have?
2
What are different versions of the same gene known as?
Alleles
A person has genotype Hh - which letter represents the dominant allele and which represents the recessive allele
H - dominant. h - recessive
In cats - H represents long hair and h short hair. Cat 1 has genotype Hh, cat 2 also has genotype Hh - what is the chance their offspring will have short hair?
25% - possible combinations are HH (long hair), Hh (long hair), hH (long hair), hh (short hair) - you can use a punnet square to work this out
Rosalind Franklin is a famous scientist - what is she best known for?
Her research leading to the discovery of the structure of DNA
Name the scientists who won the Nobel prize for the discovery of the structure of DNA
James Watson, Francis Crick and Maurice Wilkins
What is the purpose of the fallopian tube?
Transport the egg from the ovary to the uterus
What kind of cells are found in the fallopian tube that help the egg move through it?
Ciliated cells/cilia
What is the purpose of the ovary?
Stores and releases egg cells
What is the cervix?
This is a narrow opening between the vagina and uterus
In which part of the female reproductive system does a foetus develop?
Uterus
What fluid/s can be transported in a male urethra?
Urine or semen
What fluid/s can be transported in a female urethra?
Urine only
What is the purpose of the glands?
Add fluid to the sperm to make semen. The fluid provides nutrition for the sperm to give it the energy it requires to swim
What is the purpose of the testes?
Production of sperm
What hormone is produced by the testes?
Testosterone
What hormones are produced by the ovaries?
Oestrogen and progesterone
Why are the testes outside of the body?
Lower temperature is better for sperm production
What is the period of life called between childhood and adulthood
Adolescence
What is puberty?
the period during which adolescents reach sexual maturity and become capable of reproduction.
What controls the changes that happen during puberty?
Hormones (in males - testosterone, in females - oestrogen and progesterone)
Give 3 examples of male changes during puberty
voice breaks, hair grows on face and body, body becomes more muscular, testes start to produce sperm, pubic and underarm hair grows, sexual organs grow and develop
Give 3 examples of female changes during puberty
pubic and underarm hair grows, sexual organs grow and develop, voice deepens gradually, hips get wider, breasts develop, menstruation starts
The menstrual cycle is approximately how many days long?
28
What happens on the first day of the menstrual cycle?
Menstruation (period) starts
What is menstruation (a period)?
The lining of the uterus comes away and exits through the vagina as blood.
What is ovulation?
When an egg is released by an ovary into the oviduct.
Approximately when during the menstrual cycle does ovulation occur?
Middle of the cycle (day 14)
What happens to the lining of the uterus if the egg is not fertilised?
It breaks down
What happens to the lining of the uterus if the egg is fertilised?
It does not break down
What is sexual reproduction?
The process of bringing together the egg and the sperm
What is fertilisation?
The process in which the nucleus of a sperm cell joins with the nucleus of an egg cell
Describe the journey of the sperm through the male and female reproductive system (list the parts it must pass through)
Testis - sperm duct - male urethra - penis - vagina - cervix - uterus - oviduct
Describe 2 sperm adaptations that help it perform its function
Tail - helps them swim to the egg.
Mitochondria - helps give the sperm energy.
Digestive enzymes - help the sperm penetrate the egg cell membrane.
Streamlined shape - help the sperm break down the egg’s outer layer.
Describe egg adaptations that help it perform its function (fertilisation)
Jelly coating- helps by only letting in one sperm.
Nutrients - act as a food source for the developing foetus.
How do non-identical twins occur?
When two different eggs are released at the same time and are both fertilised
How do identical twins occur?
When one egg multiplies one too many times resulting in another foetus
What do we call the period of foetel development from conception to birth?
Gestation
What is formed when the sperm nucleus fuses with the egg nucleus?
Zygote
After cell division, what does a zygote then form?
Embryo
After further cell division, what does an embryo become?
Foetus
How long is the human gestation period?
40 weeks
What are 2 functions of the placenta
Provide nutrients (food and water) to the developing foetus
Provide oxygen to the developing foetus (for respiration)
Waste substance (e.g. carbon dioxide) removal.
Where is testosterone produced?
In the testes
What precaution should you take if a chemical contains this symbol?
Environmental hazard - careful disposal is required. Do not place down the sink.
If you spill some toxic or corrosive chemicals what should you do?
Clean up immediately and wash hands thoroughly.
What precaution should you take with flammable chemicals
Keep away from heat, fire and sparks. No naked flames.
True or False - Acids are always corrosive?
False. Acids can be irritants or non-hazardous
True or False - Acids are more dangerous than alkalis?
False.
When handling irritants what precautions should you take?
Wear safety glasses. Wash spills immediately.
What colour do acids turn litmus?
Red
What colour do alkalis turn litmus?
Blue
What colour do neutral solutions turn litmus?
Purple
Is water acid, alkali or neutral?
neutral
Give 3 examples of acids found in everyday life.
Fizzy drinks, vinegar, juice, battery acid
Give 3 examples of alkalis found in everyday life.
Toothpaste, washing powder, hair dye, drain cleaner, bleach
What colour will universal indicator be in acids
Red (strong acids) orange or yellow (weaker acids)
What is the pH of a strong acid
0 or 1
What is the pH of a neutral solution
7
What is the pH of an acid?
<7
What is the pH of an alkali?
> 7
What is the pH of a strong alkali?
14
What colour will universal indicator be in alkalis?
Blue or purple
What colour will universal indicator be in neutral solutions?
Green
What colour is red cabbage indicator in neutral solutions?
Purple
What colour is red cabbage indicator in acids?
Red or pink
What colour is red cabbage indicator in alkaline solutions?
Green
Which element do all acids contain?
Hydrogen
What contains hydroxide ions?
Alkaline solutions
What reaction occurs if we add an acid to an alkali?
Neutralisation
When naming salts, sulfuric acid will form a….?
________ sulfate
(the blank space would be the metal from the alkali e.g. copper sulfate)
When naming salts, hydrochloric acid will form a….?
__________ chloride
(the blank space would be the metal from the alkali e.g. sodium chloride)
When naming salts, phosphoric acid will form a….?
____________ phosphate
(the blank space would be the metal from the alkali e.g. calcium phosphate)
When naming salts, nitric acid will form a….?
____________ nitrate
(the blank space would be the metal from the alkali e.g. copper nitrate)
When naming salts, ethanoic acid will form a….?
___________ ethanoate
(the blank space would be the metal from the alkali e.g. sodium ethanoate)
Sodium hydroxide makes what kind of salts?
Sodium
e.g. sodium chloride
Potassium hydroxide makes potassium salts
Potassium
e.g. potassium chloride
Acid + alkali -> ______ + ______
Salt + water
What is a base?
Any substance that neutralises an acid forming salt + water
Is an alkali a base?
Yes! It is a soluble base
Why are insoluble bases usually preferred to alkalis where neutralisation is required? e.g. indigestion tablets, soil pH adjustment
If too much alkali is added it will dissolve and make an alkaline solution. If too much insoluble base is added, the substance remains neutral because it does not dissolve.
Give some typical properties of metals
Strong, high melting point, good conductor of heat and electricity, shiny when polished.
metal + acid ->
Salt + Hydrogen
(remember MASH!)
How do we test for hydrogen?
Squeaky pop with a lit splint
How do we test for carbon dioxide?
Turns limewater cloudy
How do we test for oxygen?
Relights a glowing splint
metal carbonate + acid ->
salt + water + carbon dioxide
What do you call a mixture if the solid settles out of the liquid if left to stand still?
Suspension
What do you call a cloudy mixture where the solid does not settle out of the liquid if left to stand still?
Colloid
What do you can a mixture where the solid is dissolved in a liquid
Solution
What is a solution?
A mixture where a solid dissolves into a liquid
Which “s” describes something that will dissolve in a liquid
Soluble
Which word describes something that won’t dissolve in a liquid
Insoluble
When a solution contains the maximum amount of liquid that will dissolve in it, this is known as
Saturated
What is solubility?
The amount of a substance that will dissolve in a given amount of liquid
What do you call the substance that will dissolve in a liquid to make a solution
Solute
What do you call a liquid into which other substances will dissolve
Solvent
When a substance is dissolved in a liquid what happens to the overall mass?
Stays the same. Nothing “disappears” - you have the same number of atoms before and after.
What happens to solubility as temperature increases?
It increases
List the 8 energy stores
Chemical, kinetic, gravitational potential, elastic potential, thermal, nuclear, electrostatic, magnetic
List the 4 energy pathways
Electrical, mechanical, heating, radiation
Is an object is stationary and then starts moving, which energy store has increased?
Kinetic
If I raise an object into the air, which energy store has increased?
Gravitational potential
What is the unit of power?
watt, W
How do you calculate power?
power = energy/time
How many watts in a kilowatt?
1000
In fuel bills, energy is given in kWh - what is this unit?
kilowatt hours
Name 3 non-renewable energy resources
Coal, oil, gas, nuclear
Name 3 renewable energy resources
Wind, hydroelectric, solar, wave, geothermal, tidal, biomass
Name 3 fossil fuels
Coal, oil, gas
How were fossil fuels formed?
Formed from the remains of plants and animals: coal was formed from dead trees and plants; while oil and gas were formed from the remains of marine life that died millions of years ago. As they were buried deeper and deeper enormous pressure and heat turned them into coal/oil/gas
What is released when fossil fuels are burnt
carbon dioxide (and other greenhouse gases)
Increasing the number of fossil fuels in the atmosphere increases what effect?
The greenhouse effect
What fuel is typically used in nuclear power stations?
uranium
As the Earth’s temperature increases due to an increase in the greenhouse effect, this can lead to…?
climate change
Some fuel is burnt to heat water. Describe the energy transfer that takes place. Use the word “store†and “pathwayâ€
The chemical store of the fuel is transferred to the thermal store of the water via the heating pathway.
Water in a reservoir falls and drives a turbine which spins. What is wrong with the following description of the energy transfer:
Gravitational potential store to kinetic store
You need to specify the object the store is associated with e.g. the gravitational store of the water is transferred to the kinetic store of the water as it falls, which is transferred to the kinetic store of the turbine.
How do you calculate energy efficiency?
Efficiency = 100 x useful output/total input
What is the golden rule of energy transfers?
Energy cannot be created or destroyed. Energy in = energy out.
When will heat transfer occur?
When there is a temperature difference between two objects
What is the difference between temperature and the thermal store?
The thermal store also takes into account the mass of the substance
How do particles move in a warmer substance?
Faster (remember temperature is a measure of the average kinetic energy of the particles)
Why are solids the best conductors?
Particles are closely packed and regularly arranged allowing vibrations to pass from one particle to another easily.
Why are metals good conductors?
They contain free electrons which can gain energy and travel throughout the material.
What are the three types of heat transfer?
Conduction, convection, radiation
What states of matter can convection occur in?
Liquids and gases
As you heat a liquid or gas, what happens to the kinetic store of the particles?
Increases
As you heat a liquid or gas, what happens to the spaces between the particles ?
Increases
As you heat a liquid or gas, the heated part becomes _________ dense?
Less
What is wrong with the following statement - “as you heat a substance, the speed of movement of the particles increases and they expand”
The particles do not expand. The space between the particles expands.
Where do convection currents occur in real life? Give 2 examples
Near radiators, in kettles or fluid in a pan on the stove, in the atmosphere, within the Earth’s core, hot air balloons…
What is the main difference between radiation and conduction and convection?
Conduction and convection rely on particles.
What kind of wave is infrared radiation?
Transverse
If we increase the temperature of an object, what happens to the infrared radiation it emits?
It increases
Which surfaces are the best emitters and absorbers of radiation?
matt black
Which surfaces are the worst emitters and absorbers of radiation?
Shiny white or silver
Why do we use insulators?
To reduce unwanted energy transfers by heating
List 3 features in a home that can reduce unwanted energy transfers?
Draft excluders, double glazing, carpets, curtains, cavity wall insulation, loft insulation, radiator reflectors, fireplace chimney balloons
What are the main chemical elements found in plastic?
Carbon and hydrogen
In a plastic, short chain m__________ are made into long chain p__________. The process is known as _________________________.
monomer, polymer, polymerisation
Which element (beginning with C ) is the fundamental building block of life?
Carbon
Name a process that removes carbon dioxide from the atmosphere?
Photosynthesis, dissolving atmospheric CO2 into seawater
Name 2 processes that add carbon dioxide to the atmosphere?
Weathering of limestone, combustion of hydrocarbons, respiration from animals and plants
When carbon dioxide dissolves in water, what happens to the pH?
It decreases - the water becomes more acidic.
By which process does carbon dioxide enter a plant?
Photosynthesis
Which gas makes up 78% of our atmosphere?
Nitrogen
Approximately how much oxygen is there in the air we breathe?
0.21
Which layer of the Earth’s atmosphere do we live in?
Troposphere
What happens to the atmosphere as you gain altitude?
It becomes less dense
The Sun’s energy reaches the Earth and is a_______________by the surface. The energy is emitted as i______________ (heat) radiation
absorbed. Infrared
Give two examples of greenhouse gases
water vapour, carbon dioxide, methane and nitrous oxide
What do greenhouse gases do?
Absorb infrared radiation emitted by the Earth’s surface. This causes the temperature of the atmosphere to increase.
