108481
| Question | Answer |
| What did the ancient Greeks think about how the universe was situated? | They thought the Earth was the centre of the Universe |
| What are the two models called for how the planets and sun and the earth move | Geocentric model and the heliocentric model. |
| What does the heliocentric model mean? | It means that the Earth and planets all orbit the Sun which is at the centre of the universe. |
| what does the geocentric model state? | The Geocentric model states that the Sun, planets and stars all orbit the Earth in perfect circles. |
| Who proved that the heliocentric model is the correct model for today? How did he do this? | Galileo - watched Jupiter using a telescope. He saw three stars in a line near the planet. When Galileo looked again later the next day, the 'stars' had moved in the wrong direction that he was expecting. After a week of observation, a fourth star appeared. They all seemed to be moving with Jupiter rather than away from it. Then he realised that these were not stars but moons. |
| Who thought of the Geocentric model? | Ptolemy |
| The invention of the telescope helped lead to the discovery of which planet? | Uranus |
| Apart from telescopes, what else can tell us a lot about the universe? | Visible light |
| Why can we see objects like stars? | This is because they are huge, very hot and give out lots of visible light |
| Why can we see planets in our Solar System? | Because they reflect sunlight |
| What do telescopes do? | They magnify images, making objects be seen in more detail. |
| What are converging lenses used for? | to focus light |
| what is a converging lense? | It is convex (bulges outwards) it causes parallel rays of light to converge to a focus. (focal point) |
| Describe the focal point. | The point where rays hit the lens parallel to the axis. |
| NOTE : | Each lens has a focal point in front of the lens and one behind. |
| What is a refracting telescope made up of? | an objective lens and an eyepiece lens |
| What happens in a refracting telescope? | The rays from the object (star) are parallel when they reach the objective lens then are converged to form a REAL image at the focal point. The rays of light from the REAL image enter the eyepiece lens. The lens then spreads them out so they leave at a wider angle than they entered. This means the light rays fill more of your retina and makes the image looks bigger. |
| What is the incident ray? | It is the ray that will pass through the focal point when it's reflected |
| What does a reflecting telescope use? | Mirrors and a Converging lens |
| What are the seven types of electromagnetic (EM) waves? -start from the shortest wavelength- | Radio waves, Microwaves, Infrared, Visible light, Ultra violet, X-rays, Gamma rays |
| Which EM wave has the highest frequency? | Radiowaves |
| Which EM wave has the smallest frequency and is the most dangerous? | Gamma rays |
| Which EM wave has the biggest wavelength? | Gamma rays |
| What did Herschel discover in 1800? How? | Infrared Radiation - he split white light through a prism. Then measured the temperature of each colour. He noticed it got hotter from violet to the red end of the spectrum. He measured the temp' just pass the red end, he found that there, there was the highest temperature. |
| Who discovered Ultraviolet radiation, when? | Ritter, 1801 |
| How did Ritter discover UV radiation? | Ritter knew that silver chloride turned white to black when exposed to light. So, his experiment was to measure how long silver chloride strips changed when exposed to different colours of light. In a dark room, he saw that the strip changed quickest when exposed to light nearer the blue end of the spectrum. He tested just beyond the violet part of the spectrum, there he found the quickest change of all. |
| What are the dangers of Microwaves? | heat human body cells, (could link to brain tumours...nothing is proved yet.) |
| What are dangerous about infrared radiation? | they have the same heating effect as microwaves but higher frequency. Skin BURNZ |
| What are the dangers of Ultraviolet radiation? | cell mutations or destruction, Sunburn = skin cancer, and Eye damage. - more energy and a higher frequency than infrared radiation. ( it is 'ionising') |
| What are the dangers with gamma/x-rays? | Cell mutation or destruction leads to tissue damage or CANCER - VERY HIGH frequency waves, also ionising and carry MUCH more energy than UV rays. |
Want to create your own Flashcards for free with GoConqr? Learn more.