the second one was very nice, soft and smooth because anna's mum helped us :D and yeh, the icing was toadstool style^^ a red mushroom with white circles on it :D i didnt get to see it yet ): because we ran out of time... i hope it looks good tmr! anywayyss, i mustnt waste time blogging! hav to study for science skills exam tmr; everyone seems to be stressing :@ that means i must stress too! theres 3 topics being tested - universe, light and earth's crust.
i am going to give an overview of the topics ;) if u dont want to read, then BUHBYES!
universe; its expanding! how? cosmic background radiation - the left overs of wat was left from the bigbang! hydrogen to helium ratio - the formation of chemical elements began from this! red shift - galaxies and stars are moving further away from us! doppler effect - the change in wavelength and pitch as an objet moves awaay or towards us... this can also occur with LIGHT!
bigbang from singularity( a single point where the universe exploded out of) - matter&antimatter(annihilate each other) to form.. - photon(left over from annihilation) forms.. - quarks(clump together) to form.. - protons (beginning of the simplest atom) - hydrogen - helium - ATOMS/ELEMENTS ^^
aftergloww? the left over radio waves after the creation of the universe!
dark matter? the subatomic particles left over from bigbang, responsible for drawing clouds of gas together! forms planetesimals - young planets!
the future! does the universe expand forever? MAYBE! three cases;
1. open universe - low enough mass, expand at decreasing rate. thus, galaxies& stars will cease to shine. WE DIE IN A DARK COLD PLACE! D:
2. closed universe - high enough mass, expansion STOPS. gravitational attraction pulls everything close together and we all fall into this one hole. BLACK HOLEEE!! it's the reversal of the bigbang D:::
3. Flat universe - everything stops expanding but no reverse.
4. Accelerating universe - expand more&more... because of a mysterious force; DARK ENERGYYY! ohhh, sppoooky! :L
life of a star; raw ingredients(nebula) - gas come closer together(protostar) - main sequence star(our SUNN!!)
death of a star; fuel runs out, depends on size- if like our sun, will produce red giant! because it uses up helium as fuel producing carbon making it expand!! then dies into a white dwarf :D if its HUMUNGOUSNESS! then it expands to form red supergiant! then a huge explosion; SUPERNOVA! the remains are neutron star! (pulars are rotating neutron stars with strong magnetic field!
light; refraction is the bending of light as it moves into different mediums. refractive index/ optical density is whether light slows or speeds up as it moves into a different medium. illusion is wen our brain constructs an image based on where we think light comes from. total internal reflection occurs when light travels from a dense medium to a less dense medium, the light cant escape the medium its in! its when the angle btw the normal and the light ray is greater than the critical angle! (critical angle is when light ray travels along the 2 mediums) optical fibres uses total internal reflection to trap light; it sends information, is cheaper, thinner, more durable and can carry more info!!
lenses; CONVEX- curved out and CONCAVE - curved in! upright - same way as original object! inverted - wrong way round! enlarged - BIGGERR! diminished - salller! magnified - image size divided by object size! focal length - distance from lens to image!
colour; dispersion - when colours split from white light into spectrum of colours! ROYGBIV! primary colours - RGB secondary colours - YCM, complementary colours are 2colours that make white light!
earth's crust; supercontinent-Pangaea,breaks into 2 smaller supercontinents-Gondwana&Laurasia.Continental drift is when continents move apart. What's the evidence supporting this?
1. coal(decomposed plants) was found in antarctica - its now to cold for plants to grow!
2. debris from glaciers was found in africa - its now too hot for glaciers in antarctica!
3. fossils of the same million yr old plants and animals hav been found on the same continent!
4. rock layers of mts form different continents matched each otehr !
5. when volcanoes form, they match the earth's magnetic field at that time. these rocks found in different continents point in different directions! but when put together, they point the same way!
STRUCTURE OF THE EARTH; we live on crust, underneath is tectonic plates which float of liquid rock; asthenosphere. lithosphere is the upper mantle and crust. inner core is solid, outer core is liquid!
THEORY OF PLATE TECTONICS: convection currents - when hot molten rock rises and cools, it moves the tectonic plates.
PLATE BOUNDARIES::::::
-spreading plates; constructive because they produce new rocks
-collision; destructive bcause they destroy rcks
- transform or scraping; conservative, they dont create or destroy!
weakened line - fault. rift valley is rock that goes down! horst is rock that goes up! magma is iside volcano, lava is outside!
focus - point where earthquake starts. epicentre - straight above the focus, on crust.
seismic waves; body - P & S waves. surface - RAYLEIGH or LOVE.
P wave is fastest, then S then surface. P travel thru earth; solid&liquid. S only travels thru solid. surface only travels on SURFACE :L P is compression wave or longitudional - push&pull motion. S is transverse wave, up&down movemet like water.
refraction occurs when waves travel thru different densities of rock which changes speed and direction!
OKAY! thats all. im too tired to go on! :DDD hope u learnt something from me here ;)
wish me goodluck tmr plz! byeeeee!
thanhhhh^^
Labels: anna, cake, crust, exam, light, science, study, universe
