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ARTICLE

How elements are formed

Our world is made of elements and combinations of elements called compounds. An element is a pure substance made of atoms that are all of the same type. At present, 116 elements are known, and ...

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Solids, liquids and gases

Water is the only common substance that is naturally found as a solid, liquid or gas. Solids, liquids and gases are known as states of matter. Before we look at why things are called solids ...

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Non-Newtonian fluids

Many people have heard of Sir Isaac Newton. He is famous for developing many scientific theories in mathematics and physics. Newton described how ‘normal’ liquids or fluids behave, and he ...

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Absolute dating

Geologists often need to know the age of material that they find. They use absolute dating methods, sometimes called numerical dating, to give rocks an actual date, or date range, in number of ...

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The ocean and the carbon cycle

The ocean plays an important role in the global carbon cycle. Carbon moves in and out of the ocean daily, but it is also stored there for thousands of years. The carbon cycle Carbon is a chemical ...

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Positive and negative effects of UV

The Earth’s atmosphere blocks most of the Sun’s UV radiation from penetrating through the atmosphere. The small amount that gets through has both positive and negative effects. Positive ...

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Relative dating

Relative dating is used to arrange geological events, and the rocks they leave behind, in a sequence. The method of reading the order is called stratigraphy (layers of rock are called strata) ...

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ARTICLE

Waves as energy transfer

‘Wave’ is a common term for a number of different ways in which energy is transferred: In electromagnetic waves, energy is transferred through vibrations of electric and magnetic fields. In sound ...

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Development of the periodic table

Although elements such as gold, silver, tin, copper, lead and mercury have been known since earliest times, the first scientific discovery of an element occurred in 1649. Hennig Brand, a German ...

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Uses for UV

There are a variety of ways we put ultraviolet (UV) radiation to good use. Our skin and UV When we expose our skin to UVB, it stimulates the production of vitamin D, which our bodies need. Window ...

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Preparing samples for the electron microscope

Electron microscopes are very powerful tools for visualising biological samples. They enable scientists to view cells, tissues and small organisms in very great detail. However, these biological ...

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Melting and freezing

Water can exist as a solid (ice), liquid (water) or gas (vapour or gas). Adding heat can cause ice (a solid) to melt to form water (a liquid). Removing heat causes water (a liquid) to freeze to ...

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Carbon cycle

The carbon cycle can seem like a complex process because there are many interacting parts. Carbon is found in both organic (living) and inorganic (non-living) forms. Before we discuss the cycle ...

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ACTIVITY

What is the Earth system?

There are many interacting systems that make up the Earth, many of which are dynamic. These notes discuss the importance of understanding the concept of systems with emphasis on the water cycle ...

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Impacts of biotechnology on society

Biotechnology has helped improve the quality of people’s lives for over 10,000 years. Today’s biotechnologies vary in application and complexity. However, they all have potential to change our ...

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The water cycle

The Earth has a finite amount of water. The water that is here today is the same water that will be here in 20 or even 20 million years’ time. So, if all living things use water, how is it that ...

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How microscopes magnify

A microscope is something that uses a lens or lenses to make small objects look bigger and to show more detail. This means that a magnifying glass can count as a microscope! It also means that ...

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Classifying and identifying ferns

Scientists currently consider that New Zealand has approximately 230 species of fern in about 50 different genera. They are widely distributed throughout the country, including around 42 species ...

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What is energy?

This is both a simple and complex question. Energy is in everything – it is often described as ‘the ability to do work’. Almost all food energy comes originally from sunlight. The chemical ...

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Chemical reactions and catalysts

A chemical reaction involves a chemical change, which happens when two or more particles (which can be molecules, atoms or ions) interact. For example, when iron and oxygen react, they change to ...

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Earth system

Trying to understand how this planet we call home works can seem confusing – there are so many things going on at once! Scientists break down the way the Earth system works to a number of ...

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Types of electron microscope

Electron microscopes were developed in the 1930s to enable us to look more closely at objects than is possible with a light microscope. Scientists correctly predicted that a microscope that used ...

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