Flashcards
Physics 1
Cards in this deck (17)
- 1Physics 1
- 2The solar system -Geocentric: The planets orbit the Earth -Heliocentric: The planets orbit the sun-Geocentric: published by Ptolemy in 130 CE he was believed because his ideas fit with the church
-Heliocentric: published by Copernicus in 1543, he had evidence because he saw the four moons orbiting Jupiter, but he was not believed
- 3ways of observing the universe -the naked eye can see stars/planets -telescopes see more distant stars -photographs provide a record of observationGalileo Galilei was the first astronomer to make observations using telescopes.
- 4Reflection and Refraction Light travels in waves, normally in straight lines unless it is reflected or refracted.Reflection: When light bounces off a boundary between different materials
Refraction: When light passes from one material to another.
When light passes through a boundary between two transparent materials at an angle its direction will change
- 5Telescopes The first telescope used lenses to gather light and to magnify the imageRefracting telescope: uses two converging lenses.
Objective lens: brings rays of light to a distant object to a point to form an image.
Eyepiece lens: acts as a magnifying glass and magnifies this image
- 6Reflecting telescope uses a curved mirror to gather light from distant objects and a converging lens as an eyepiece to magnify the image.
- 7Waves Waves transfer energy without transferring matter. Waves can be described by their: -Frequency- measured in hertz (Hz) -Speed- metres per second (m/s) -Wavelength- amplitudeWaves
Longitudinal waves: Sound waves and seismic P waves are longitudinal waves
Transverse waves: waves on water surface, electromagnetic waves and seismic S waves - 8Colours of the visible spectrum are: Red, orange, yellow, green, blue, indigo and violetRed has he longest wavelength and the lowest frequency.
Violet has the shortest wavelength and the highest frequency.
- 9William Herschel discovered infrared radiation. He used a prism to split lights into the colours of the visible spectrum. He used a thermometer to investigate the heating effect from each colour. The heating increased from violet to red. He investigated the region beyond the red. He found an even bigger heating effect. He had discovered infrared radiationJohann Ritter discovered ultraviolet radiation. He used a chemical called silver chloride which turns black when light shines on it. Silver chloride turns black faster in violet light than it does in red light. It turned black even faster when it was exposed to invisible radiation beyond the violet part of the spectrum. Ritter had discovered ultraviolet radiation
- 10All electromagnetic waves are transverse waves. All electromagnetic waves travel at the same speed in a vacuumElectromagnetic spectrum:
Radio waves, micro waves, infrared radiation, visible light, ultraviolet, x-rays and gamma rays
- 11Radio waves have the longest wavelength and the lowest frequency.Gamma rays have the shortest wavelength and the highest frequency
- 12Ionising radiation All electromagnetic waves transfer energy. Amount of energy transferred depends on the frequency of the wave. The higher the frequency, the more energy the wave transfers.Effects of ionisation
Energy transferred by ionising radiation removes electrons from atoms to form ions.
Ions are reactive and can cause mutations to the DNA in cells.
Damaged DNA can lead to cancer - 13Galaxy: A collection of millions of stars. The sun is part of a galaxy called the milky way.There are billions of other galaxies. All the galaxies make up the Universe
- 14Exploring the Universe- modern telescopes Development:impact Greater magnifications: we can observe galaxies that are far away recording observations using photography or digital cameras: we can gather more dataCan be made with greater precision: We get clearer images
Telescopes that can detect other parts of the electromagnetic spectrum: we can observe objects in space that emit more radio waves, infrared, ultraviolet, or x-rays than visible light - 15Alien Life- signs of life -water on the planet -Oxygen levels -chemical changesspace probes fly past planets or go into orbit around them, the probes can take images of other planets and send the information back to Earth.
- 16Life cycle of a star 1. Nebula 2. protostar 3. main sequence star 4. red giant/red supergiant 5. white dwarf/supernova 6. black dwarf/ neutron star or black holeStars take billions of years to go through these sequences (not millions)
- 17Big band theory- The whole Universe started out 3.5 billion years ago. The Universe expanded from a tiny particle in space and is still expanding today.Steady State theory-
The Universe has always existed. It is expanding and new matter is being created as it expands
