science Flashcards
What is the definition of the word ‘sphere’
a round, solid figure
What does the prefix “bio” mean?
life
What is the biosphere?
The place where life exists on planet earth
What are the three components that form part of the biosphere?
the atmosphere,
the lithosphere
the hydrosphere
what are the elements of the lithosphere?
soil
rocks
sand
what are the elements of the hydrosphere?
all the water on earth, in all its forms (liquid, solid and gas)
What does the atmosphere consist of?
All the gases
What are the three most important gases in the atmosphere?
Oxygen
Nitrogen
Carbon Dioxide
What word is used to describe something to do with water?
Aquatic
What word would be used to describe organisms that live in the ocean or salt water?
Marine
What would a marine biologist study
the life of organisms in the ocean
What are the 7 life processes of all living organisms?
Movement
Respiration
Sensitivity
Growth
Reproduction
Excretion
Nutrition
What is cellular respiration?
The process where organisms release energy from their food
What is the meaning of the word “sustain”?
To keep something alive or in existance
What is the meaning of the word “sustainable”?
Something that is able to continue to exist for a long period of time
What are the requirements of living organisms in order to sustain life?
energy
gases
water
soil
favourable temperatures
Where do plants get there energy from?
The sun
Where most organisms (other than plants) get their energy from?
the food they eat (such as plants and other animals)
What do all living things require for cellular respiration?
oxygen
___?_____ is used to release energy from nutrients, and ___?______ and _______?_____ is produced as a waste product of respiration?
Oxygen is used to release energy from nutrients, and
Water and carbon dioxide is produced as a waste product from respiration.
What gas do plants require to photosynthesise?
Carbon dioxide
What gas do plants excrete?
Oxygen
What gas do humans excrete as a waste product when they breathe out?
Carbon dioxide
What do most plants depend on for support, water and minerals?
soil
Plants that do not grow in soil, such as mosses and orchids are called….
epiphytes
Where do epiphytes get their minerals and water from?
The air and rain
Explain why Earth is said to be in the solar systems “Goldilocks zone”.
It is neither too close nor too far from the sun, therefore, not too hot nor too cold and has favourable temperatures to sustain life
What is a hypothesis?
An OBSERVATION and EDUCATED GUESS on what the OUTCOME will be on an INVESTIGATION
The hypothesis is stated BEFORE starting the investigation and must be written in the FUTURE TENSE.
If you are wanting to investigate if eating a lot of sugar will make you gain weight? What kind of variable would the amount of sugar you eat be? Explain why?
The amount of sugar you eat will be an INDEPENDANT VARIABLE
because
you are IN CONTROL of HOW MUCH sugar you would eat.
An INDEPENDENT VARIABLE is a variable that you are IN CONTROL of.
In an investigation to see if eating a lot of sugar would make one gain weight, what would be the DEPENDENT VARIABLE, and why?
The dependent variable would be the thing that I am OBSERVING in the investigation - HOW MUCH weight I am gaining or losing.
It will change DEPENDING on the independent variable.
Explain what a controlled variable is.
The variable that stays the same in each test in order to follow out a fair test.
EG. Each participant must do the same exercise but consume different amounts of sugar.
Each organism is able to survive in their environment because they have acquired the characteristics for them to thrive in that particular environment, we say they have
ADAPTED to their environment.
What term describes the great variety of living organisms on Earth and their varied habitats?
biodiversity
Describe the grouping system that the Greek philosopher, Aristotle came up with 2400 years ago.
He divided all organisms into either plant or animal.
He then divided all animals into - with blood and without blood.
Lastly he divided the animals into 3 groups: walkers, flyers and swimmers.
Did Aristotle’s grouping system work?
No
Describe the classifying system that Carl Linnaeus developed in the 1700’s.
He classified organisms according to:
similarities
functions
and relationship with other organisms
What five kingdoms are all living organisms divided into?
Animals
Plants
Fungi
Protists
Bacteria
What kingdom do humans belong to?
Animal kingdom
The kingdom “bacteria” is also often referred to as….
Monera
Each kingdom is divided into smaller and smaller groups called….
divide this group into the smaller groups that follow
Kingdom - Phylum - Classes - Order - Family - Genus - Species
(Remember: King Phil Cuts Open Five Green Snakes)
What does “Binomial nomenclature” mean?
Calling things by two names.
The common name and the scientific name.
The scientific name would refer to the genus that the organism belongs to plus the species within the genus.
The scientific name for which animal is Loxodonta africana?
An elephant
Why are human beings also called Homo sapiens?
They belong to the Genus - Homo and the species “sapiens.
In what ways would we compare plants?
The way that they move
What and how they get their food or nourishment
How they reproduce
Mushrooms, truffles, yeast and morels are all examples of…
fungi
Why does fungi play an important role in our biosphere?
They are decomposers and break down dead ORGANIC matter and
return nutrients to the soil for plants to use.
Organisms that cannot be seen with the naked eye are called…
microscopic
What are the 2 distinct groups of the animal kingdom,
name and describe these two groups.
Vertebrates - Animals with back bones.
Invertebrates - Animals without back bones.
What type of skeleton do vertebrates have?
An endoskeleton (a skeleton INSIDE the body)
Invertebrates are divided into 5 phyla. Name them:
Sea Sponges
Jelly Fish
Round Worms
Molluscs
Arthropods
What phylum do vertebrates belong to?
Chordata
What percentage of animals are vertebrates?
2%
What are the 5 classes of vertebrates?
Fish
Amphibians
Reptiles
Birds
Mammals
Fish are divided into two groups. Namely…
Cartilaginous Fish - (skeletons made of cartilage)
Bony Fish - (skeletons made of bone)
Is a whale shark a whale or a fish?
Give 2 intersting facts on it.
It is a whale.
It is the largest fish in the world and
it only eats plankton
Give an interesting fact about seahorse.
The male seahorse becomes pregnant.
The female squirts her eggs into the male’s puch, which he ferilizes and incubates until they hatch.
Explain what is meant when saying, “reptiles are ectothermic”
Reptile cannot regulate their own body temperature and depend on the environment for heat.
What is the difference between turtles, terrapins and tortoises?
Turtles live in salt water (the ocean)
Terrapins live in fresh water
Tortoises live on land and do not swim
Explain the meaning of the term “endothermic”
Animals that are able to maintain their body temperature at a constant level.
describe the characteristics of mammals
All mammals are vertebrates
Almost all mammals are endothermic
Mammals give birth to live young and feed them milk
Mammals have hair on their bodies
Mammals have teeth
Mammals breath using their lungs
Why do Cheetahs hunt during the day?
There is less chance of them losing their catch to larger cats who hunt at night.
Name 2 characteristics of arthropods.
All arthropods are invertebrates.
They also have jointed (segmented) legs
Which animal is responsible for the most human deaths each year
the mosquito
Which animal is the largest land-living arthropod on earth?
Why is it called that?
The coconut crab
It can crack coconuts with its pincers
Which animals belong to the group of Molluscs?
Slugs
snails
squid
Octopuses
mussels
oysters
other soft bodied animals
How can we easily classify plants?
The shape and size of their leaves
If they have flowers and the shape of their petals
The length and depth of their roots
Their type of root system
Their are two distinct groups of plants referring to how they reproduce, name these two groups.
Plants with seeds
Seedless plants
How do ferns, mosses and algae reproduce?
They produce spores.
Explain what Linchen is.
Linchen is actually two different organisms growing together.
fungus and green algae.
The fungus absorbs water from the environment and provides an environment for the algae to grow.
The green algae photosynthesis and provides food for itself and for the fungus.
Plants that produce seeds in flowers are called….
angiosperms
Plants that produce seeds in cones are called….
gymnosperms
Flowering plants are divided into 2 groups: called:
monocotyledons - bears a single seed leaf
dicotyledons - bears 2 seed leaves
What do all angiosperm plants have in common?
roots
stems
leaves
flowers
fruits
seeds
There are two basic ways in which reproduction can take place.. name them:
Asexual reproduction - the parent organism does not need to mate
sexual reproduction - 2 parent organisms mate and their DNA combine.
The male part of the flower is called the…
stamen (includes the anthers and filament)
What does the stamen produce?
Pollen
What is the role of the filaments?
They are stalk like structures that support the anthers
What is the female organ of the plant called?
The pistil (which includes the style and ovary)
Which part of the plant become seeds after fertilisation?
The ovules
Which part of the plant receives pollen during fertilisation
The stigma
A long tube that connects the stigma with the ovary and the ovules is called…
The style
What is pollination?
The process where pollen from the stamen is transferred to the stigma of the flower.
Fertilisation occurs and the plant is able to produce seeds or fruit.
How are flowers able to be pollinated?
Either by wind or animals such as bees and butterflies drink the nectar from flowers, moving pollen from one flower to another.
What is the difference between fruits and vegetables?
Fruits are ripened ovaries of flowering plants and contain seeds.
Vegetables are other parts of the plants, such as their leaves, roots and stems.
is a pumpkin a fruit or vegetable?
a fruit. (It is the ripened ovary and contains seeds)
Name different ways plants disperse theirs seeds.
Gravity
Animals
Explosive force
Wind
Water
How do humans reproduce?
When the sexual organs reach maturity, the sperm from the male combines with the egg cell from the female. The DNA from the parents is combined.
Explain the physical changes in human beings during puberty.
The sexual organs start to mature
Pubic hair starts to grow on the genitals
Females will start secreting hormones, menstrual bleeding will occur and become fertile. (able to reproduce)
Males will start producing sperm in their testicles which is able to fertilise the egg in females.
Body shape changes such as widened hips, increased body fat and enlarged breasts in females,
Males bones and muscles increase in size.
Body odour and acne as there is changes in hormones and skin produces more oils
The green colour in plants is from something called….
chlorophyll
What are three classes of arthropods?
Insects
Arachnids
Crustaceans
What three parts are all insects bodies made up of?
The head
The thorax
The abdomen
Describe the legs of insects
All insects have 6 jointed legs
(3 pairs of jointed legs)
How do insects sense their environment?
They have a pair of antennae to sense their environment
Give three examples of arachnids
Spiders
Ticks
Scorpions
Are spiders vertebrates or invertebrates?
invertebrates
What two parts are arachnids bodies divided into?
cephalothorax
abdomen
Describe the legs of arachnids
They have 4 pairs of jointed legs
(8 legs altogether)
How many eyes do arachnids have?
8
What do arachnids eat?
Arachnids are mostly carnivores
What is a scavenger?
An animal that does not hunt but eats animals that are already dead
A plants root system that has many short roots is called….
fibrous root system
Describe a tap root system
One long main root with shorter roots coming out of the sides of the main root
Give three differences between monocotyledon and dicotyledon plants
Mono - 1 cotyledon / Di - 2 cotyledon
Mono - flower parts are in 3’s or multiples of 3
Mono - long strap like leaves, parallel veins /
Di - leaves of many shapes - branch like veins
Mono - stems stay / Di - stems harden as plant ages
Mono - fibrous roots / Di - Tap root
What do you call any method that is used to prevent pregnancy
contraception
What needs to take place in a flower before fertilization is possible?
pollination
What is it called when a male sex cell fuses with a female sex cell?
fertilization
The female sex cells that are found inside the ovary of the flower are called the ….?
ovules
What is pollination?
The transfer of pollen from the anther in a flower to the stigma in a flower
Give 2 examples of wind pollinated plants
mielies
grasses
What is the hormone called that causes puberty in males
testosterone
What is the hormone that causes puberty in females?
Oestrogen
What are the three main parts of the female reproductive system?
The ovaries
The uterus
The vagina
Where are the egg cells stored in the female reproductive system?
The ovaries
What are the egg cells in the female reproductive system called?
The ova
When does the female produce egg cells?
She is born with them
How often do females release an unfertilized ovum?
About every 28 days
What is the space inside a woman’s body where a baby grows called?
The uterus
Where is sperm made?
In the male’s testes
What is the scrotum?
The bag outside the males body where the testes are held
How are the testes connected to the penis?
By a long thin tube
How does sperm leave the body?
Through the penis
How long does pregnancy usually last in the female human?
40 weeks / 9 months
For the first 2 months a developing baby is called….
an embryo
What is a developing baby called after the first 2 months?
A foetus
Where does a developing foetus get its food and oxygen from?
Its mother
What happens during labour?
The baby turns itself so that the head is pushing down on the cervix.
The strong muscles in the uterus push the baby out through the vagina
What happens if a mother is unable to birth her baby naturally?
An operation called a caesarian, where doctors will cut open the mothers stomach and uterus to take the baby out
How does one avoid pregnancy after puberty?
Choosing not to have sex
Using contraceptives such as condoms or the contraceptive pill.
What is menstruation and why do females have it?
If pregnancy does not happen , blood flows from the lining of the uterus out through the vagina.
The thick lining is needed for a fertilized egg to attach to, to become pregnant.
Is contraceptive 100% effective?
No
What is the ONLY way a female will not become pregnant?
By not having sexual intercourse
What can be other consequences of having unprotected sex?
The danger of getting a STD - sexually transmitted disease, such as
HIV,
What is AIDS?
Acquired Immune Deficiency Syndrome caused by the HIV virus.
The disease attacks the immune system which helps the body fight illness and infection.
When the immune system cells drop below a certain level the person will be diagnosed with AIDS.
There is no cure for HIV or AIDS.
How is HIV and AIDS transmitted from one person to another?
Through unprotected sexually intercourse. (not using a condom)
Infected blood entering another persons body.
From an infected mother to child during child birth or breastfeeding
How is HIV or AIDS NOT transmitted?
Sweat, tears and vomit
Touching, Kissing and hugging
Mosquitos
Sharing knives, forks and cups
Can you tell if someone has an STD (sexually transmitted disease) by looking at them?
No
An illness where the body cannot break down sugar.
Diabetes
A condition where there is a shortage of red blood cells in your body, which causes tiredness and weakness
Anaemia
What are genes?
Genes are found inside the chromosomes inside cells of the body. They carry information about your ancestors and determine which traits you will inherit, such as eye colour, height, allergies and illnesses, etc
Can a history of disease in your family put you at greater risk of getting the same diseases? (such as diabetes, heart conditions, cancers etc)
Yes
What is matter?
Matter is the term for anything that has mass and takes up space
Able to bend easily without breaking
flexible
What is boiling point?
The point where a material changes from a liquid to a gas
What is melting point?
The point where a material changes from a solid to a liquid
Unable to be bent or forced out of shape
rigid
The strength of an object that stops it from being crushed or change shape when being pushed or squeezed
comprehensive strength
What is tensile strength?
The strength of an object that prevents it from breaking apart when being pulled apart
What is conductivity?
How easily an object or material allows heat or electricity to flow through it
A substance that does not allow heat or electricity to flow through it?
Insulator
What is greenhouse gas?
A gas like carbon dioxide that traps heat in the atmostphere
What does it mean if something is biodegradable?
It can be broken down / decomposed by bacteria
What does thermal mean?
relates to producing or using heat
Everything around us is made up of….
matter
In what forms can matter be?
liquid, solid or gas
We chose materials for certain things depending on their physical properties, such as their:
Strength
Flexibility
Melting point
Boiling point
Electrical conductivity
Heat conductivity
Why does water have a different boiling point in Johannesburg and Durban?
Because Johannesburg has a lower air pressure
Do all substances have the same boiling point or melting point?
No
How does electricity move?
By electrical current
Which metal is a good conductor?
copper
What material is a good insulator?
plastic
What material would be a good material to make a cooking pot out of and why?
Stainless steel, because it is a good thermal conductor and has a high melting point.
What would be a good material to make a cooking pots handles out of and why?
Plastic, does not conduct heat so will not be too hot to pick the pot up
What do we call the physical property that describes how something feels when you touch it?
texture
What are 5 words that would describe the properties of a material?
Smooth / Rough / Soft / Hard
Expensive / Cheap / Colourful
Durable / Rigid / White / etc
Name 5 natural resources
Grass
Stone
Gold Ore
Cotton Plant
Trees
Coal
Name 5 processed materials or products
Tyres
Table
Glass
Oil
Paper
ETC
What do we call something that should NOT change in a fair test.
A constant
What do we call something that we change in a fair test?
A variable
What is a fair test?
It is a controlled test, experiment or investigation to answer a question
What does a scientist always start a fair test with?
A question that needs an answer
Why do we only change one variable at a time when doing a fair test
Changing one variable at a time will give an accurate answer
How many variables and how often should they be changed in a fair test?
One at a time
What is mining?
The process of taking precious minerals or resources from the Earth
Why is mining harmful to the environment?
Often, chemicals are used in the process of mining, which end up in water supplies.
The chemicals are harmful to plants, animals and humans.
Dust that blows off the mines is harmful to the people who live nearby.
Mining requires a lot of energy, therefore a lot of coal and oil needs to be burnt, releasing poisonous gases into the environment
The poisonous gases get trapped inside the atmosphere, causing the planet to become hotter. We call these gases Greenhouse gases.
What are plastics made of?
Chemicals called polymers
Why are plastics a problem?
Plastics are NOT biodegradable and litter our environment.
When plastics are burnt; it releases harmful chemicals into the environment
Many plastics end up in the ocean and kill fish and birds
What is the name of the main electricity supplier in South Africa?
Eskom
What are the pros (positives) of mining?
Mining provides many jobs for people and
raw materials to export overseas.
We are able to manufacture goods from the raw materials that are useful to us and to sell and export.
Why is plastic useful to us?
It is cheap
strong
easy to shape
light weight
What processed material is responsible for most litter
plastic
What processed material is responsible for most litter
plastic
Why is their a government tax on plastic shopping bags?
The government is trying to encourage people to use reusable shopping bags to prevent more waste and litter.
Name one fossil fuel that plastic is made from
oil
How long does it take plastic to break down?
thousands of years
What is a mixture
When two or more substances with DIFFERENT physical properties are mixed together
Small parts that make up matter are called…
particles
Explain the definition of the word ‘dissolve’
When the particles of a SOLID substance spread BETWEEN the particles of a LIQUID so that you can no longer tell the two substances apart.
The solid has dissolved into the liquid.
A solid that does NOT dissolve into a liquid is…
insoluble
What is a pure substance?
A substance that is made up of only ONE kind of particle
The method used to seperate a solid from a liquid using a filter is called…
filtration
What is a solution?
A mixture made up of a solid dissolved into a liquid.
EG. Sugar dissolved into water is a sugary water solution
What is the substance that is dissolved into the liquid called.
(eg. the sugar that is dissolved into water)
A solute
What is a solvent
The LIQUID that a solid is dissolved into
What is evaporation?
The process where a liquid changes into a gas.
The liquid is heated and evaporates.
How can a solute be separated from a solvent.
Through evaporation
A method of separating two liquids through different boiling points is called…
distillation
What method is used to purify a liquid?
distillation
What is condensation?
The change of state of a gas to a liquid.
This normally happens when a gas is cooled.
A scientific method of separating a mixture into two different parts using dyes and machines to process the mixture at different speeds to separate them is called….
chromatography
Taking waste and turning it into something useable is called…
recycling
Waste that comes from plants or animals and can be broken down naturally by decomposers is called…
organic waste
A place where our waste is taken and buried is called …
A landfill
What is methane?
A greenhouse gas that is made by rubbish which is breaking down landfills
What gases are found in the air that we breathe
Oxygen
Nitrogen
Carbon dioxide
Is the air that we breathe a pure substance or a mixture?
A mixture
In a sugar, water and salt solution, what are the the solutes?
sugar and salt
In a sugar, water and salt solution, what are the the solutes?
sugar and salt
What would be a suitable method of separating maize seeds and stones
hand-sorting
What would be a suitable method of separating sand and stones?
sieving
Is using a magnet a suitable method for separating paper and plastic? Why?
No, neither paper nor plastic is magnetic
What is a good method to separate a liquid and a insoluble solid?
filtration
What would be a good method to separate a solution?
Evaporation
Where does water go in the process of salt harvesting?
It evaporates
What speeds up the process of salt harvesting.
The sun and wind
Distillation involves ____________________ of the solvent, followed by _________________________ and then ___________________________________________________________….
Distillation involves EVAPORATION of the solvent, followed by CONDENSATION, and then COLLECTION OF THE CONDENSED LIQUID
What does liquid turn into when heated?
Water vapour
How can we reuse organic waste?
We can use it to create compost, which is then used to feed plants nutrients.
What are 5 consequences of poor waste management?
Pollution of our soil, which is harmful to plants and animals.
Diseases can be spread through house flies and rats that are attracted to waste.
Blocked sewages can be a health hazard and spread disease
More land is needed for landfills which could be used for farming instead
Drains become blocked causing flooding
Valuable materials are wasted instead of being recycled
a substance that eats through certain materials like clothing and metals,
and burns the skin. We would describe this substance as…
corrosive
What is meant by the term ‘Caustic’
able to burn or corrode organic tissue by chemical reaction
dyes that change colour in acids and bases
indicators
paper stained with a substance called litmus, used to indicate acids,
bases and neutrals
Litmus paper
The four different tastes are…
Sweet
Salty
Bitter
Sour
What are the little bumps on the tongue called?
taste buds
Why is the sense of taste important
It is important for our survival as it stops us from eating food that can be harmful such as unripe or rotten food.
What do acids / acidic foods taste like?
Sour
How do acids feel on the skin?
Rough
Are acids safe and why?
Many acids are not safe as they are corrosive
Where would you find citric acids?
in citrus foods like oranges, limes and lemons
Where would you find lactic acid?
In sour milk
Where would you find carbonic acid
In fizzy soda drinks
Where would you find hydrochloric acids?
In stomach juices
Where would you find ethanoic acids?
In vinegar
Can you name an example of a strong acid
hydrochloric acid or sulphuric acid
What is the opposite of acids?
Bases
Can you name the properties of bases?
Bases taste bitter
Bases feel slippery on the skin
Bases can be caustic and can be dangerous to taste or feel
What are neutral substances?
Neither base nor acid
Are neutrals dangerous?
No
Name some things that are neutral.
Cooking oil
Pure water
A salt or sugar water solution
How can you make a neutral substance?
By reacting an acid with a base.
What is a pH scale?
It is used to measure the strength of an acid or a base.
What is the pH of a neutral?
pH7
What is the pH of an acid?
From pH 0 to pH 6
What is the pH of a base?
From pH 8 to pH 14
The higher the pH the stronger the….
Base
Red Litmus paper turns ______________ in a base
Blue
Blue Litmus Paper turns ____________ in an acid
Red
What colour will the litmus paper turn if the substance is neutral?
The colour will stay the same
What is the periodic table
A list of all the elements arranged in a table
A pure substance that cannot be broken down is called…
An element
What is an atomic number?
the number of protons in one atom of an element
The total number of protons and neutrons in a nucleus is called…
atomic mass
A chemical element that conducts heat and electricity…
a metal
What is a semi-metal?
An element that shares some properties of metals and some properties of non-metals
What is a semi-conductor
An element or substance that only conducts electricity when it is heated up
Define ‘brittle’
breaks easily
Define ‘ductile’
Can be stretched
Define malleable
Can be bent and flattened or shaped
A stable gas that does not combine with other elements is called …
a noble gas
What are the rows on a periodic table called?
periods
