Whitley Academy Science Faculty Year 10 into Year

Whitley Academy Science Faculty Year 10 into Year 11 Summer Homework

What to do …. . Use this booklet to create flash cards on the topics below to help you in your lessons in September, and help you relearn some of the most difficult areas from the end of year exam. • • Waves Magnification and microscopy. Series and Parallel. Periodic table. Please ensure you don’t create cards for parts in the book that are ‘biology only’/’physics only’/’chemistry only’ unless you have chosen triple science as an option. Also, do not create cards for parts labelled ‘HT’ if you know you will be doing foundation tier. Create cards for HT if you are aiming for higher tier (grades 5 to 9).

Learn. IT! Know. IT! Waves in air, fluids and solids • • • Transverse and longitudinal waves Properties of waves Reflection of waves (physics only) Sound waves (physics only) (HT) Waves for detection and exploration (physics only) (HT)

Transverse and Longitudinal Waves Transverse Wave Longitudinal Wave In a transverse wave the particles within the wave move perpendicular (at 90 o) to the direction the wave is travelling. This is the wave produced in a rope when it is flicked up and down. Examples of transverse waves are: Water waves, electromagnetic (light) waves and guitar strings. Remember, the particles in a wave move up and down or backwards and forwards only. It is energy, NOT the particles, that move from one place to another! Longitudinal waves are compression (squash) waves where the particles are vibrating in the same direction as the wave movement. This is the wave produced when a spring is squashed and released. Examples of longitudinal waves are: Sound waves and a type of seismic (P) wave.

Transverse and Longitudinal Waves Wavelength (m) – the distance from one point on a wave to the same point on the next wave. Amplitude (m) – the waves maximum displacement of a point on a wave from its undisturbed position. Frequency (Hz) – the number of waves passing a point per second. Period (s) - the time taken to produce one complete wave. The displacement of a transverse wave is described as peaks and troughs. In a longitudinal wave these are described as compressions and rarefactions.

Properties of waves Wave speed and wave period calculations Wave speed is the speed at which energy is transferred by the wave (or how quickly the wave moves) through the medium it is travelling in. Wave speed (m/s) = Frequency (Hz) x Wavelength (m) v=fλ Wave period (T) is the time it takes one complete wave to pass a point (in seconds). Period (s) = 1 / Frequency (Hz) T = 1/f The wave opposite has a frequency of 0. 5 Hz and a wavelength of 6 cm (0. 06 m). Calculate the wave period and the wave speed. Wave period = 1/f T = 1/0. 5 = 2 s Wave speed = f x λ v = 0. 5 x 0. 06 = 0. 03 m/s

Properties of waves Method for measuring the speed of sound waves in air 100 m The cannon fires and the stopwatch is started (you can see a flash of light which takes almost zero time to travel 100 m). When the sound reaches the observer the stopwatch is stopped. The time was 0. 3 s This will give the time for sound to travel 100 m. Speed (m/s) = Distance (m) / Time (s) Speed of sound = 100 / 0. 3 = 333. 3 m/s In the laboratory, a sound from a loudspeaker passes two microphones a set distance apart. The time recorded for the sound to travel this distance is measured and speed is calculated using the same formula as above.

Properties of waves Method for measuring the speed of ripples on a water surface Strobe A ripple tank is used to make waves which are seen under the glass tank. A strobe light has its frequency of flashes adjusted until the wave appears stationary – this is the frequency of the water wave. Then, the wavelength of the water wave is measured by using a ruler to measure the distance from one peak to the next peak (white line to white line). This is converted to metres. Wave speed (m/s) = Frequency (Hz) x Wavelength (m) If the frequency of the water wave is 5 Hz and the wavelength is 0. 6 cm: wave speed = 0. 5 x 0. 006 = 0. 03 m/s

Sound waves changing medium (physics only) When a sound wave travels from one medium to another e. g. air to water, the frequency remains the same. This is because frequency is a property of the object producing the sound, not the medium it travels through. Air Water The sound wave will travel faster in water than air. Remember, Wave speed (m/s) = Frequency (Hz) x Wavelength (m) or f = v / λ. So, if the frequency remains the same, as velocity increases, the wavelength must also increase proportionally. If a sound wave has a frequency of 260 Hz: Speed of sound in air = 330 m/s. Speed of sound in water = 1500 m/s. λ in air = 330 / 260 = 1. 27 m λ in water = 1500 / 260 = 5. 77 m

Reflection of waves (physics only) When light waves strike a boundary they can be reflected, absorbed or transmitted depending on the substance they strike. Reflected light bounces off the object surface Transmitted light passes through the object Absorbed light heats the object Light reflected from a specular surface, e. g. a mirror, reflects at the same angle it strikes the mirror. Angle of incidence (i) = angle of reflection (r)

Sound waves (physics only) (HT) Sound waves can travel through solids causing vibrations in the solid. In the ear, sound waves cause the ear drum and other parts to vibrate which causes the sensation of sound. The conversion of sound waves to solids only happens over a limited frequency range. This restricts the human hearing range to between 20 Hz and 20, 000 Hz (20 k. Hz). Ear drum Sound waves

Waves for detection (physics only) (HT) Ultrasound waves used for detection Ultrasounds are sound waves with a higher frequency than humans can hear. Ultrasound waves are partially reflected when they meet a boundary between two different media. The time taken for the reflections to meet a detector can be used to determine how far away the boundary is. Ultrasound waves can therefore be used for medical imaging. A similar technique, using higher frequencies, can be used in industry to detect flaws and cracks inside castings. This could prevent a potentially dangerous casting being used, for example, in an aircraft engine.

Waves for exploration (physics only) (HT) Seismic waves used for exploration Earthquake epicentre Earthquakes produce P and S waves. P waves: fast longitudinal; travel at different speeds through solids and liquids. S waves: slower transverse; cannot travel through liquids. This information can be used to determine the size, density and state of the Earth’s structure. As S waves do not penetrate the outer core, they can not be used to determine whether the inner core is liquid or solid. The study of seismic waves provided new evidence that led to discoveries about parts of the Earth which are not directly observable.

Waves for exploration (physics only) (HT) Echo sounding Echo location or SONAR uses high frequency sound waves to detect objects in deep water (shipwrecks, shoals of fish) and measure water depth. Ultrasound waves travel at 1500 m/s in sea water. The transmitter sends out a wave which is received 4. 6 s later. The depth of water under the ship can be calculated as: Distance (m) = speed (m/s) x time (s) so: distance = 1500 x 4. 6 = 6900 m Remember, this is the time to go to the bottom and back. Therefore depth = 6900 /2 = 3450 m

Cell structure - Microscopy light microscope First ones used in 1590’s electron microscope First ones used in 1960’s Feature Light (optical) microscope Electron microscope Radiation used Light rays Electron beams Max magnification ~ 1500 times ~ 2 000 times Resolution 200 nm 0. 2 nm Size of microscope Small and portable Very large and not portable Cost ~£ 100 for a school one Several £ 100, 000 to £ 1 million plus Resolution: The shortest distance between two objects that can be seen clearly. Video - Types of microscopes

Cell structure - Microscopy Electron microscopes have a higher magnification and resolution than light microscopes. This means that scientists can see more sub- cellular structures (structures within the cells). us le nuc ho r nd c ito m Light microscopes image can let us see structures like nuclei and mitochondria. ia mi to ch on dr io n Electron microscopes image can let us see the internal structures of a chloroplast and mitochondrion.

Cell structure - Microscopy You can calculate the magnification of an image by using the equation: magnification M = size of image I real size of the object A MAGNIFICATION: the number of times bigger the image looks compared to the object IMAGE: what is viewed through the microscope lenses OBJECT: the ACTUAL specimen under the microscope WORKED EXAMPLE 1: A magnified animal cell structure has a diameter of 6 mm. The actual diameter of the structure is 0. 15 mm. IMAGE OBJECT Calculate how many times the structure has been magnified. M= I A M= 6 0. 15 M = 40 You may need to to write your answers in standard form. You may need to be able rearrange to change the subject of the equation.

Cell structure - Microscopy magnification M = size of image I real size of the object A WORKED EXAMPLE 2: The actual length of a cell structure is 30�� m. It is magnified 40 times. OBJECT(A) MAGNIFICATION (M) Calculate the length of the magnified cell structure in mm. Rearrange the equation to make I the subject Ax M= I x. A A I= Mx. A I = 40 x 30 You may need to to write your answers in standard form. Multiply both sides by A Cancel out the As Put I on the left of the equation I = 1200 �� m I = 1. 2 mm To convert to mm you need to divide by 1000

Cell structure – Microscopy Making a wet mount slide e. g. onion cells • Place a thin section of the specimen onto slide. • Place a drop of water in the middle of the slide or stain the specimen. • Gently lower cover slip onto the specimen without trapping air bubbles. Drawing what you see • Clear line drawing – no shading • Label main cell structures • Add a title and the magnification. • Soak up any excess liquid with a paper towel. • Switch on the light source and place your slide on the stage. • Use the lowest objective lens and turn the focusing wheel to move the lens close to the slide. • Slowly adjust the focusing wheel until you can see a clear image. • Increase the magnification by changing the objective lens and re-focus. See GCSE Practical Guide - Biology – Microscopy on Huddle - Microscopy Practical guide

Cell structure - Culturing microorganisms (biology only) Bacteria multiply by binary fission (a cell division where two identical cells are formed). In the right conditions cells can divide as often as every 20 minutes. • • • Bacteria can be grown in the lab A culture medium (agar) used containing an energy source (carbohydrate) and minerals. Petri dishes and agar must be sterilised before use to kill microorganisms. Inoculating loops used to transfer bacteria after being heated in a Bunsen flame. The lid of the Petri dish should be sealed with tape to stop other microorganisms getting in (must not be fully sealed so oxygen can get in) In school, Petri dishes are incubated at 25°C to reduce risk of growth of pathogens that might be harmful to humans. Effectiveness of disinfectants and antibiotics on bacteria experiment • Agar inoculated with BACTERIA. • Paper discs containing antiseptics and antibiotics placed on bacteria and left to grow. Water disc used as a CONTROL. • If bacteria don’t grow around the disc then the chemical is effective at killing bacteria. • Area where bacteria don’t grow is called ZONE OF INHIBITION. Bacteria lines See GCSE Practical Guide - Practical guide Microbiology

Series and Parallel Circuits Series circuits consist of one loop of wire. For components connected in series: • there is the same current through each component • the total potential difference of the power supply is shared between the components • the total resistance of two components is the sum of the resistance of each component. Rtotal = R 1 + R 2 resistance, R, in ohms, Ω

Series and Parallel Circuits consist of two or more loops (branches) of wire. For components connected in parallel: • the potential difference across each component is the same • the total current through the whole circuit is the sum of the currents through the separate components on each loop (branch) • the total resistance of two resistors is less than the resistance of the smallest individual resistor.

Periodic table The elements are arranged in order of increasing atomic number. Elements with similar properties are in columns, known as groups. Elements in the same group have the same number of electrons in their outer shell. The rows in the table are called periods Group = electrons in outer shell Period = number of shells It is called a periodic table because similar properties occur at regular intervals Group = 7 Period = 3

1808 John Dalton published a table of elements that were arranged in order of their atomic weights, which had been measured in various chemical reactions 1864 John Newlands published the law of octaves. However the table was incomplete and elements were placed in inappropriate groups Periodic table 1869 Dmitri Mendeleev overcame Dalton’s problem by leaving gaps for the elements that he thought had not been discovered and in some places changed the order based on atomic weight (e. g. Argon and Potassium). Elements with properties predicted by Mendeleev were eventually discovered. Early 20 th Century - Scientists began to find out more about the atom and knowledge of isotopes explained why the order was not always correct.

Periodic table The elements can be divided into metals and non-metals. 1 H 2 3 4 5 6 7 Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca Sc Ti Rb Sr Y 0 He V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn Fr Ra Ac Rf Db Sg Bh Hs Mt ? ? ? Metals Non-metals Shiny Mostly solid Dense and strong Malleable Good heat and electrical conductors Dull Low density Weak Brittle Poor heat and electrical conductors Elements that do not form positive ions are non-metals Elements that tend to form positive ions are metals Non metals – found towards the right and towards the top of the periodic table Most elements are metals – found towards the left and towards the bottom of the periodic table