volcanoes

Question 1

what is the distribution of shield volcanoes?

Answer 1

near divergent plate boundaries where magma can rise directly from the mantle.

Question 2

what is the distribution of stratovolcanoes?

Answer 2

near convergent plate boundaries where there is subduction and build-up of pressure.

Question 3

what is the gradient of stratovolcanoes?

Answer 3

steeply-sloping sides

Question 4

what is the gradient of shield volcanoes?

Answer 4

gently-sloping sides

Question 5

what type of summit shield volcanoes have?

Answer 5

broad summit

Question 6

what is the summit of stratovolcanoes?

Answer 6

steep summit

Question 7

what is the base of stratovolcanoes?

Answer 7

gentler base

Question 8

what is the base of shield volcanoes?

Answer 8

increases in size as lava accumulates after successive eruptions.

Question 9

which volcanoes has a secondary cone?

Answer 9

stratovolcanoes. May develop as magma from the vent seeps into the sides of the cone and erupts

Question 10

what are the materials erupted from shield volcanoes?

Answer 10

lava and ash

Question 11

what are the materials erupted from stratovolcanoes?

Answer 11

lava, ash,pyroclastic flow and lahars

Question 12

what type of lava does shield volcanoes contains?

Answer 12

low-silica lava that flows easily and spreads out over a large area before solidifying.

Question 13

what type of lava does stratovolcanoes have?

Answer 13

they contain high-silica lava that flows slowly and spreads out over a small area before solidifying.

Question 14

what type of eruption does shield volcanoes have?and their characteristics?

Answer 14

non-explosive eruption due to low silica lava that does not trap gas.The gases will be able to escape easily as magma reaches the earth´s surface,causing an outward explosion

Question 15

what type of eruption does stratovolcanoes have?and its characteristics?

Answer 15

explosive eruption due to high-silica lava that traps gases.these gases will expand as the magma reaches the earth´s surface,causing an outward explosion.

Question 16

Describe the steps the students should take to collect the wind speed data.

Answer 16

Stand at an open area where wind flows freely. [1]

Read the wind speed off the display on the anemometer. [1]

Question 17

describe the formation of sea breeze.

Answer 17

During the day, the land heats up faster than the sea. [1]
Over land, warmer air expands & rises, creating an area of low pressure. [1]
As a result, air pressure over land is lower than the sea. [1]
Thus, wind blows from sea (high pressure) to land (low pressure), lowering the temperature of coastal areas. [1]

Question 18

One programme to reduce climate change

Answer 18

plant a tree programme that maintain Singapore’s status as a Garden City
Residents donate money to buy a tree or take part in tree planting events
limitations : Trees take many years to mature, it takes time to materialise
E.g. Fast-growing trees like angsanas, raintrees planted by Nparks took 25 years to reach full height