Functions of Life Unicellular (single-celled) and multicellular (many cells) organisms must carry out the following functions to stay alive: Metabolism - all the enzyme-catalysed reactions occurrin...
Cell Theory Until microscopes became powerful enough to view individual cells, no-one knew for certain what living organisms were made from A scientist called?Robert Hooke?came up with the term "ce...
Edexcel IGCSE Physics 復(fù)習(xí)筆記 8.3.3 Galactic Red-shift Galactic Red-shift The Doppler effect affects all types of waves, including?light Light emitted from stars and galaxies will be at a c...
Edexcel IGCSE Physics 復(fù)習(xí)筆記 8.3.2 Doppler Shift The Doppler Effect Usually, when an object emits waves, the wavefronts spread out?symmetrically If the wave source moves, the waves can bec...
Edexcel IGCSE Physics 復(fù)習(xí)筆記 8.3.1 The Big Bang Theory The Big Bang Theory Around?14 billion years ago,?the Universe began from a?very small region?that was?extremely hot?and?dense Then th...
Edexcel IGCSE Physics 復(fù)習(xí)筆記 8.2.5 Hertzsprung-Russell Diagrams Hertzsprung-Russell Diagrams Stars are classified using the Hertzsprung-Russell (HR) diagram This is a plot of: The?luminosi...
Edexcel IGCSE Physics 復(fù)習(xí)筆記 8.2.4 The Brightness of Stars Absolute Magnitude Astronomers measure the brightness of stars at a standard distance using the?absolute?magnitude scale This is ...
Euler's Method: Second Order How do I apply Euler’s method to second order differential equations? A?second order differential equation?is a differential equation containing one or more second deri...
Edexcel IGCSE Physics 復(fù)習(xí)筆記 8.2.3 The Life Cycle of Larger Stars The Life Cycle of Larger Stars A?large star?is one that is much?larger?than the?Sun Stars that are larger than the Sun hav...
