To examine the effects of natural emergency events, students need to have some understanding of how those events occur. The following scientific investigations will help build these understandings.
Our Earth is not a solid rock but is made up of a series of different layers. These are the crust, the mantle, the inner core and the outer core. The crust is the outside layer that we live on and is a series of solid plates that float on the liquid mantle below.
The plates are constantly moving due to convection currents occurring in the mantle layer. This layer is liquid magma and heats up and cools down resulting in convection currents.
Some of these plates move apart. Such as the plates running down the middle of the Atlantic Ocean.
Some plates move directly into each other. Such as the collision of the Australian Plate with the Pacific Plate forming the Southern Alps in the South Island.
Others form subduction zones, where one plate moves under the other. This occurs in New Zealand in the North Island, causing a line of volcanoes and geothermal areas.
When plates move we get small cracks called fault lines. As fault lines move there can be either a gradual release of energy or a sudden release of energy resulting in earthquakes.
The Richter Scale measures the size of an earthquake. It is a measure of the energy released. When earthquakes are deep in the Earth their energy is the same. But the shaking does not feel as strong as shallow earthquakes.
The amount of shaking you feel is another way to describe earthquakes. We call this the intensity. The intensity is stronger when you are close to the earthquake source and when the earthquake is shallow. It decreases the further away you are. We describe earthquakes by the energy released, which is their magnitude. We also describe them by how strong the shaking feels, which is their intensity.
Build a quake-safe structure or design a building that could withstand an earthquake. Use materials like playing cards, Lego, wooden blocks and collected items from the school garden.
Investigate to find the answers to these questions.
There are many parts of Aotearoa that a flood could affect. In fact, floods are the most common emergency event around the country.
The water cycle is when water circulates from clouds to the soil to streams to rivers to the oceans and then returns to the clouds.
When a lot of rain falls, it can be too much for the soil to soak up and streams can fill up. When streams and rivers fill up faster than they can flow out to sea, the water runs onto land and causes a flood. Urban flooding can also happen when there is too much water for the storm water drains to clear.
Use a flood map to adjust imaginary floodwaters to show how much of the land could end up under sea level.
The crust of the Earth may be solid rock but it has also changed over millions of years to form soil. This process is always happening. Soils come in different varieties. Soils wear down or wear away because of water, wind and human activities. We call this erosion.
Where soils have built up over time, a sudden event such as a heavy rain, flooding or an earthquake can quickly move a large amount of soil. This is a landslide. But, this also depends on the type of soil and how ’sticky’ the soil particles are. ‘Sticky’ soil particles have lots of friction. They hold together better than ‘smooth’ soil particles, which slide easier. It also depends on factors such as tree roots, which help hold soil together. Gravity can also play an important part, as the steeper the slope of the land the greater the effect of gravity.
Above the crust is a layer of air that is essential to all living things, called the atmosphere. Our atmosphere divides into different layers. Closest to the ground is the troposphere, which is about 8–15 kilometres thick. This is the layer where most of our weather occurs as it is the most dense.
The air in the atmosphere is always moving as it heats up and cools down. This causes convection currents that we experience as wind. Clouds are also a visible sign of these convection currents. This means that the air becomes unstable. When unstable air meets lots of moisture, there is the potential for thunderstorms.
Use to represent hot and cold air. Blue water represents the cold air mass and red water represents the warm and unstable air mass. The warm water (air) rises by approaching cold water (a front). This is where thunderstorms would form.
Have the students take photos of the experiment and annotate the photographs afterwards.
Tsunami form when there is an earthquake that causes a vertical shift in the bottom of the ocean. This displaces the water, which causes a series of waves to form. The waves travel out from the source like ripples travelling across a pond after you drop a pebble in it. Tsunami waves can travel across entire oceans. Landslides can also cause tsunami.
To help students understand how damaging a tsunami can be, introduce the concept of shoaling. Shoaling helps explain why tsunami waves get taller as they approach the shore. The taller they are, the more damage they can cause.
Volcanoes are mostly found along the borders between plates in the Earth’s crust. The Earth’s plates move around because they are floating on top of a layer of liquid rock called magma. Magma forms the layer we call the mantle.
This layer is under a lot of pressure. If there is a gap in the plates, the liquid rock can be forced out. Just like when you shake a bottle of fizzy drink and then open it.
When the magma is forced out above ground, it cools to form solid rock. This is lava. Lava can flow in sheets to form layers of new rock, but it can also build up hills and mountains, which we call volcanoes.
New Zealand’s active volcanoes are on the North Island or in the sea near the North Island. Volcanoes can produce lava as well as ash, lahar and a range of different gases. Some of these extremely poisonous.
The shape and size of a volcano depends on the materials in the magma, the force of the explosions and its age. Volcanoes can be extinct, dormant or active.
The most common volcanic hazard is ash. It is very scratchy because volcanic ash is tiny pieces of sharp rock. When an eruption happens, the wind can carry ash hundreds of kilometres. During the volcanic eruption of Mt Ruapehu in 1996, a thin layer of ash covered farms, cars and buildings.
Make small volcanoes out of gelatine and show how pressure in a volcano causes the eruption of magma.
These resources help to teach students about the science of earthquakes.
These resources help to teach students about the science of floods.
Read a New Zealand perspective on floods on Te Ara, The Encyclopedia of New Zealand.
These resources help to teach students about the science of landslides.
For information on how to prepare your home and protect your whānau, visit the Be Prepared section of the Earthquake Commission's website.
Read a New Zealand perspective on landslides on Te Ara, the Encyclopedia of New Zealand.
These resources help to teach students about the science of storms.
Learn more about storms on Get Ready.
These resources help to teach students about the science of tsunami.
Read a New Zealand perspective on tsunami on Te Ara, the Encyclopedia of New Zealand.
These resources help to teach students about the science of volcanoes.
Read a New Zealand perspective on volcanoes on Te Ara, the Encyclopedia of New Zealand.