Across
- 1. FUSION The process in which two small nuclei combine to form a larger one, releasing energy (e.g. hydrogen combining to form helium). This happens in stars, including the Sun
- 4. Lump of rock and ice in a highly elongated orbit around the Sun
- 7. The tiny central part of an atom (made up of protons and neutrons).
- 9. The maximum disturbance of a wave motion from its undisturbed position
- 10. The layer of rock between the crust and the outer core of the Earth (approximately 2900 km thick)
- 11. theoretical beginning of the Universe, when energy and matter expanded outwards from a point
- 13. A collection of thousands of millions of stars held together by gravity
- 14. WAVE A wave in which the particles of the medium vibrate in the same direction as the wave is travelling. Sound is an example
- 16. The distance between one wave crest (or wave trough) and the next
- 17. The number of waves passing a set point, or emitted by a source, per second
- 18. A dwarf rocky planet, generally orbiting the Sun between the orbits of Mars and Jupiter.
- 20. Event in which rocks break to allow tectonic plate movement, causing the ground to shake
- 22. SPEED The speed at which waves move through a medium
- 23. RIDGE A line of underwater mountains in an ocean, where new seafloor constantly forms
- 25. Longitudinal shock waves following an earthquake that can travel through the molten core of the Earth; they change direction at the boundary between different layers of the Earth
- 27. The movement of solids at the Earth’s surface (for example, soil, mud, and rock) caused by wind, water, ice, gravity, and living organisms
Down
- 2. The centre of the Earth. It’s made mostly from iron, solid at the centre and liquid above.
- 3. The shift of lines in a spectrum towards the red (longer wavelength) end, due to the motion of the source away from us
- 4. The movement that occurs when hot material rises and cooler material sinks.
- 5. Molten (liquid) rock
- 6. Scientist who studies rocks and the changes in the Earth
- 8. Angle between two imaginary lines from two different observation points on Earth to an object such as a star or plant, used to measure the distance to that object
- 12. DRIFT: Slow movement of continents (land masses) relative to each other
- 15. Spherical object orbiting the Sun, smaller than a planet and larger than an asteroid
- 19. Faint patch of light in the night sky. With good telescopes we can see that some are gas clouds, others are distant clusters of stars.
- 21. BRIGHTNESS: The apparent brightness of a star as seen from Earth; a dim star close to Earth may appear brighter than a bright one that is further away
- 22. EQUATION The speed of a wave is equal to its frequency multiplied by its wavelength
- 24. A rocky layer at the surface of the Earth, 10 – 40 km deep
- 26. CYCLE Continuing changes in rock material, caused by processes such as erosion, sedimentation, compression, and heating
- 28. BRIGHTNESS: A measure of the light emitted by a star compared to the Sun, taking into account how far away it is