1.1 Characteristic of the idea

Harlen (Harlen, ed., 2015) characterizes this idea as follows: Radiation from the Sun heats the Earth’s surface and causes convection currents in the air and oceans, creating climates. Below the surface heat from the Earth’s interior causes movement in the molten rock. This in turn leads to movement in the plates which form the Earth’s crust, creating volcanoes and earthquakes. The solid surface is constantly changing through the formation and weathering of rock

1.2 Suggested level of preconception development for primary level

In the younger school age (7–11 year olds), which corresponds to primary science education, (according to Harlen‘s concept of developing Big Ideas of Science), pupils should already understand that there is air all around the Earth’s surface but there is less and less further away from the surface (higher in the sky). Weather is determined by the conditions and movement of the air. The temperature, pressure, direction, speed of movement and the amount of water vapor in the air combine to create the weather. Measuring these properties over time enables patterns to be found that can be used to predict the weather a short time ahead. Long-term patterns in the weather are referred to as the climate of different parts of the world. Much of the solid surface of the Earth is covered by soil, which is a mixture of pieces of rock of various sizes and the remains of organisms. Fertile soil also contains air, water, some chemicals from the decay of living things, particularly plants, and various living things such as insects, worms and bacteria. The solid material beneath the soil is rock. There are many different kinds of rock with different compositions and properties. The action of wind and water wears down rock gradually into smaller pieces – sand is made of small pieces of rock and silt of still smaller pieces. About two-thirds of the surface of the Earth is covered by liquid water, which is essential to life. Water is constantly recycled through processes involving evaporation from oceans and other surfaces, such as soil and plants, condensation in clouds and precipitation as rain, snow or hail.