The Sun releases a continuous stream of particles, called plasma, into space. Plasma conducts electricity and is strongly affected by magnetic fields. The Earth, which is surrounded by a magnetic field, therefore attracts plasma to its atmosphere.
To understand the importance of gases in the atmosphere, you need to know something about the structure of molecules and atoms that make up gases. Did you know that atoms are composed of protons, neutrons and electrons? Protons are particles carrying a positive electric charge (+), while neutrons have no electric charge. Together protons and neutrons form the nucleus, or centre of the atom. Electrons are particles which carry a negative (-) charge and revolve around the nucleus of the atom.
Atoms can gain, lose or share electrons. When atoms share electrons, bonds form between them, and they become molecules. Molecules may be composed of atoms from the same element or atoms from different elements. For example, an oxygen molecule (O2) is made of 2 atoms of oxygen, water molecules (H2O) are made of 2 atoms of hydrogen and 1 atom of oxygen. The small number to the right of the chemical symbol tells how many atoms of each element are in the molecule.
The Sun is made of hydrogen that is constantly being converted into helium. Try making this model to help you visualize the formation of an ionised atom.
You will need:
- Mini coloured marshmallows
- The marshmallows are nuclei and electrons, and the toothpicks represent the bonds between them. Hydrogen is the simplest atom because it has one electron. Use one toothpick to join two marshmallows. Choose a different colour for each (pink is electron, green is nucleus). You now have a Hydrogen atom. Plasma is a gas that is so hot that some electrons have been separated from the atoms. In other words, plasma is an ionised gas, a gas of nuclei and electrons.
- To simulate the heat process that divides the electrons take the Hydrogen atom and break the toothpick in half. You now have a separate nucleus and a floating electron.
Everything in plasma is either positively charged (nucleus) or negatively charged (electron). Mixed together these charged particles form plasma
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