END OF YEAR 8 SCIENCE EXAM

Question 1

What nutrients does
the human body
require

Answer 1

vitamins, minerals, protein, fats, water, and carbohydrates.

Question 2

What is the structure
and function of the digestive system?

Answer 2

breaks down food into simple nutrients such as carbohydrates, fats and proteins.

Question 3

How can lifestyle choices affect our body?

Answer 3

affect energy metabolism, cellular growth, steroid metabolism, inflammatory mediation, DNA repair and immune function.

Question 4

What is the structure
of the periodic table and how are elements arranged and grouped?

Answer 4

The chemical elements are arranged in order of increasing atomic number. The horizontal rows are called periods and the vertical columns are called groups.

Question 5

What are the main groups in the Periodic Table?

Answer 5

groups 1 and 2 (s-block), and groups 13 to 18 (p-block).

Question 6

How do groups of elements show trends in properties?

Answer 6

boiling point.

Question 7

What is static charge and how are they generated?

Answer 7

Static electricity is the result of an imbalance between negative and positive charges in an object.

Question 8

What is the nature of current, potential difference and resistance?

Answer 8

current is directly proportional to voltage but inversely proportional to resistance.

Question 9

How do series and parallel circuits differ?

Answer 9

In a series circuit, all components are connected end-to-end to form a single path for current flow. In a parallel circuit, all components are connected across each other with exactly two electrically common nodes with the same voltage across each component.

Question 10

How do magnets and electromagnets work?

Answer 10

when the coils of wire in an electromagnet have an electric current passing through them, the coils behave like a magnet.

Question 11

What are solutions and what is solubility?

Answer 11

What is Solubility? The maximum amount of solute that can dissolve in a known quantity of solvent at a certain temperature is its solubility. A solution is a homogeneous mixture of one or more solutes in a solvent. Sugar cubes added to a cup of tea or coffee are a common example of a solution.

Question 12

The nature of mixtures.

Answer 12

heterogeneous or homogeneous

Question 13

How can we use evaporation to
separate solutions?

Answer 13

to separate components of a mixture with a dissolved solid in a liquid.

Question 14

How can we use
Filtration to separate
solids from liquids?

Answer 14

The liquid particles are small enough to pass through the filter paper as a filtrate. The solid particles are too large to pass through the filter paper and stay behind as a residue.

Question 15

What is
Chromatography used for?

Answer 15

enables the separation, identification, and purification of the components of a mixture for qualitative and quantitative analysis.

Question 16

How we get energy form
food.

Answer 16

The stomach and small intestines absorb the glucose and then release it into the bloodstream.

Question 17

The law of conservation
of energy

Answer 17

energy can neither be created nor be destroyed.

Question 18

How is energy
transferred as heat?

Answer 18

by conduction, by convection, and by radiation.

Question 19

Sources of energy.

Answer 19

coal, geothermal energy, wind energy, biomass, petrol, nuclear energy,

Question 20

Work and power.

Answer 20

Work, Energy and Power - Definition, Examples, Formula, Units
Work is the energy needed to apply a force to move an object a particular distance. Power is the rate at which that work is done.

Question 21

How do we know how much energy different appliances use?

Answer 21

The wattage of most appliances is usually stamped on the bottom or back of the appliance, or on its nameplate

Question 22

How organisms are adapted to their environments

Answer 22

Structural and Behavioral Adaptations

Question 23

The concept of evolution as a way pf adapting to changes in environment.

Answer 23

natural selection

Question 24

What is variation and how is it important?

Answer 24

the variations in DNA sequences. It makes one organism different from the other organism. Variations are essential for natural selection.

Question 25

What is natural selection?

Answer 25

the process through which populations of living organisms adapt and change.

Question 26

What causes extinction?

Answer 26

overhunting or overharvesting; introduction of nonnative species, including the spread of disease; and habitat degradation or loss

Question 27

How do metals react
with oxygen?

Answer 27

a metal oxide forms.

Question 28

How do metals react
with acids?

Answer 28

Metal + acid → salt + hydrogen

Question 29

What is displacement?

Answer 29

the change in position of an object.

Question 29

Do metals react with
water?

Answer 29

Metal oxide and hydrogen gas is created when a metal and water reacts together.

Question 30

How can we extract
metals?

Answer 30

dump leaching, heap leaching, tank leaching, or pressurized leaching.

Question 31

What are the different types of rock found on Earth?

Answer 31

Igneous, Sedimentary & Metamorphic

Question 32

What is the carbon cycle and how do humans affect it?

Answer 32

Burning fossil fuels, changing land use, and using limestone to make concrete all transfer significant quantities of carbon into the atmosphere.

Question 33

How do you calculate speed?

Answer 33

speed = distance ÷ time.

Question 34

How do you show motion on a graph?

Answer 34

the steeper the graph, the faster the motion.

Question 35

Where do plants get their energy from?

Answer 35

the sun
During photosynthesis, plants trap light energy with their leaves.

Question 36

How do leaves work?

Answer 36

turning sunlight into food.

Question 37

Are there any other ways to release energy?

Answer 37

Engaging in physical activities such as running, dancing, playing sports, or practicing yoga