Year 8 End of Year Revision Quiz

Waves

What are waves caused by? Give an example. Vibrations Guitar string vibrates the air.

What do waves transfer? Energy

What is the difference between a longitudinal wave and a transverse wave? Longitudinal wave – vibrations are PARALLEL to the direction of energy transfer Transverse wave – vibrations are PERPENDICULAR to the direction of energy transfer

How do you measure the amplitude, wavelength, and the frequency of a wave?

How do you calculate wave speed?

Light

What kind of wave is light? Transverse wave Electromagnetic wave

What three things happen to light when light hits an object? Reflect Absorb Transmit

How do we see luminous objects? Draw a ray diagram. The light from the luminous object goes directly into the eye.

How do we see non-luminous objects? Draw a ray diagram. The light coming from a luminous object reflects off of the non-luminous object and then enters the eye.

How are shadows formed? When an object does not allow light to pass through, a dark area is formed which light does not reach.

Draw a ray diagram for reflection including a) the normal, b) angle of incidence, and c) angle of reflection. Angle of incidence Angle of reflection

What are the rules for reflection? Angle of incidence = angle of reflection Image is the same size as the object Image is upright Image is right/left flipped Image is the same distance away from the mirror as the object

Why do smooth surfaces reflect an image but rough surfaces do not? Smooth surfaces reflect light evenly, but rough surface scatter light in all directions.

What is refraction? When light changes direction when passing through different mediums.

Draw a ray diagram for refraction of light as it enters and exits a glass block. Reminder: Light refracts TWICE. Once when entering the glass and once when leaving the glass. Angle of incidence Angle of refraction Angle of incidence (2) Angle of refraction (2)

Why is it that objects in water appear to be in a different location then they actually are? Draw a ray diagram to show this. Light refracts when leaving the water, however, the brain thinks that light travels in a straight line from the object and the object appears at a location in a straight line from the light entering the eye.

Why is it that objects in water appear to be in a different location then they actually are? Draw a ray diagram to show this.

What is a spectrum? The spectrum of light is the continuous scale of different colours of the rainbow that are found in white light.

How can we get a spectrum using white light? We can get a spectrum from white light by dispersing the light using a prism.

Why do we see different objects as different colours? A coloured object reflects the colour of light that it appears (which then enters our eye) and absorbs all other colours.

How do coloured filters work? The colour of the filter is transmitted through, all other colours are absorbed.

What colour do objects appear under a red filter for a) a white object, b) a red object, c) a green object? Why? White object looks RED because the filter only let red light through and the white object reflects all colours so reflects the red light. A red object looks RED because the red object reflects red light. A green object appears BLACK because a green object only reflects green, absorbs the red light, so no light is reflected.

What is refraction? When light changes direction when passing through different mediums.

Sound

What type of wave is sound? Longitudinal wave Mechanical wave (needs a medium to travel through)

What causes sound waves? How do sound waves travel? Sound waves are caused by vibrations. A vibrating object vibrates the surrounding air (or liquid or solid) particles and pushes them. These particles then bump into other particles and pass the sound wave along. Then returns to its original position.

What causes sound waves? How do sound waves travel?

How does the speed of sound change in different mediums (solid, liquid, gas). Fastest through solids. Slowest through gases.

What are the differences between light waves and sound waves? Electromagnetic wave Can travel through a vacuum Transverse wave Faster than sound Faster in LESS dense materials Sound Mechanical wave Must travel through a medium Longitudinal wave Slower than light Faster in MORE dense materials (eg solids)

How does a change in the a) amplitude, b) wavelength, and c) frequency affect the sound you hear? Higher the amplitude the LOUDER the sound. The longer the wavelength the LOWER the PITCH. The higher the frequency the HIGHER the PITCH.

Compare these two sounds. Trace A and B are the same loudness. But Trace B is a higher pitch sound.

What are the five main parts of the ear and what are their functions? Outer ear (pinna) funnels sound waves into the ear. Ear canal transfers sound waves to the ear drum. Ear drum vibrates and passes on vibrations to the ear bones. Ear bones pass on the vibrations to the cochlea. Cochlea transfers the vibrations to an electrical signal. (Auditory nerve passes the electrical impulse to the brain.)

What are the five main parts of the ear and what are their functions?

How can the parts of the ear become damaged How can the parts of the ear become damaged? How can you solve these problems? Outer ear – ear canal can get blocked with wax, remove the wax Middle ear – ear drum can tear from very loud noise, usually heals by itself Inner ear – cochlear cilia can become damaged by loud or constant noise, damage is permanent, avoid very loud and long exposure to loud sounds

What is the human hearing range? 20-20,000 Hz

How is loudness measured? Decibels (Db)

Rocks

What are the three main types of rocks What are the three main types of rocks? What are the properties of each type? Sedimentary rock – weakest, rounded grains with gaps, porous, found in layers, sometimes contain fossils Metamorphic rock – strong, flattened interlocking crystals, found in layers Igneous rock – strong, interlocking crystals, not always found in layers

Compare the strength of the different types of rock Compare the strength of the different types of rock. Use their structure to explain why. Sedimentary – weakest, weak bonds between the grains and contains gaps between the grains Metamorphic – strong but can split between layers Igneous – strongest, no gaps between the crystals and not found in layers

What does porous mean? Draw a diagram of a rock that is porous. Contains gaps between grains allowing it to absorb water.

How are sedimentary rocks formed? Weathering Erosion Transportation Deposition Compaction Cementation

How are metamorphic rocks formed? High heat (from magma) and high pressure (from rock layers above) deep underground.

How are igneous rocks formed? Rocks melt into magma deep underground. Magma is forced upwards and magma or lava cools down to form igneous rock.

Draw a diagram of the rock cycle.

What is weathering. What are the two main types of weathering What is weathering? What are the two main types of weathering? How do they work. Weathering is the breaking up of rocks. Chemical weathering – chemical reactions wear away the rock Physical weathering – physical processes break apart the rock

Describe freeze-thaw weathering. Type of physical weathering, water gets into cracks in the rock, if temperature gets cold enough the water freezes and expands making the crack bigger. This eventually splits the rock.

Describe onion skin weathering. Temperature changes cause the rock to expand (hot) and contract (cold). Over time the repeated expansion and contractions cause cracks to form and the rock breaks apart.

Describe chemical weathering. Rainwater (slightly acidic) and acid rain (very acidic) react with chemicals in the rock and turn them into soluble substances that are then washed away.

Describe biological weathering. When plants grown into cracks in rocks and break them apart.

What is a fossil? Which type of rock can fossils be found in? Fossils are the remains or imprints of a once living organism. Fossils are only found in sedimentary rocks.

What is a crystal? What does it mean if the crystals are interlocking? Crystals are grains with sharp edges. Interlocking means that there are no gaps between the crystals.

How do igneous rocks with different sized crystals form? Fast cooling (above ground, extrusive) = small crystals (less time for the bonds to form to make crystals) Slow cooling (underground, intrusive) = large crystals (more time for the bonds to form to make crystals)