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It has a range of functions which are vital for our survival. The skin is structured in layers with many different components integrated in these layers to help it fulfil the many tasks required of it constantly. The skin is required as a barrier between the outside world and our internal controlled environment, it is physically tough to protect us from various "nasties", such as harmful chemicals or bacteria and viruses, it is protective towards deeper tissues against bangs and bumps, and when exposed to sunlight it produces an essential nutrient, vitamin D.
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This was because of the extra time it took for the light to cross the extra distance. He calculated that it would take about 22 minutes to cross the diameter of Earths orbit. Using these calculations R�mer found the speed of light. He measured the distance between the sun and Earth and found out that the speed of light was 125,000 miles per second. James Bradley (1728) was not satisfied, he said that starlight could cause an "aberration of light" and could cause speed of light measurements go wrong. R�mer used an Astronomical method. Hippolyte Fizeau in 1849 used an earthbound method to measure the speed of light.
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Tsunami- a huge ocean wave caused by earthquakes a. A tsunami may be as high as 30 meters when it reaches the shore 1. such waves carry enough energy to cause a lot of damage to costal towns and shore lines V. Energy may spread out as a wave travels i. when you are standing next to the speakers at a rock concert, the sound will damage your ears, however if you 100m from them, the sound is not as loud a.
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The sections are divided by how energetic the ultraviolet radiation is. Some materials will absorb the energy from ultraviolet waves and emit the energy as visible light. These materials are called fluorescent and are used for fluorescent lighting (sometimes called strip lighting) and security marking. The sun emits UV light which causes the skin to tan. Sun beds use fluorescent lighting to emit ultraviolet light to create an artificial tan. Sunbathing- Effects on the body Sunbathing has many different effects on the body both positive and negative. Positive The healing power of the sun was acknowledged by ancient civilisations long before we had identified UV rays.
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Heated air rising is an example of natural convection. Forced convection is when a pump or a mechanism moves the heated fluid. Some examples of forced convection are some types of ovens, refrigerators and air conditioners. Lava Lamp A lava lamp is an example of convection the heater in the base of the lamp heat up the fake lava. Due to the rapidly increased temp the lava expands making it less dense than the surrounding liquid. The less dense lava then floats to the top.
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Most of the energy stored in waves arises from kinetic energy; this is due to the wave having a great mass, as water is very heavy and also the speed at the waves travel. However it is possible to get power from the potential energy in waves, this will be discussed later on. Looking at Figure 1 you can see how waves develop and how they have the potential to create lots of energy. However Waves are not as consistent as the tide and therefore there is a definite problem with matching supply and demand.
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Refractrometry. Aim: Using a model Pulfrich refractometer determine the refractive index of a range of sugar solutions and hence determine the refractive index of some sugar solutions with an unknown concentration.
I predict that my graph will be proportional. This because the refractive index is proportional to the specific gravity of a concentration, which is directly proportional to concentration. Therefore my graph will appear similar as below: Apparatus: * Rectangular Perspex block * Several sheets of blank white A4 paper * Pin board * 2 tall pins * Black paper * Range of sugar concentrations * Sharp pencil * Protractor In my apparatus I have made steps to improve the sensitivity and accuracy of this investigation.
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The frequency of a wave is measured as the number of complete back-and-forth vibrations of a particle of the medium per second. Unit of frequency is Hertz (Hz). The frequency of a wave can be altered by increasing the number of vibrations per second. Increasing the frequency, increases the pitch of the wave. Any sound that can heard by a human ear is called an infrasound (20Hz to 20000Hz). Above this range the sound is known as ultrasound. Ultrasound is used to communicate underwater because its can travel long distance without a lot of distortion.
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Carry out an experiment to find a relationship between the incident angle and the refracted angle when light is shone through a rectangular Perspex block.
This causes the light to bend towards the normal until both edges are travelling at the same speed. The normal is the line from where the angled are measured. Diagram showing the refraction of light. Planning of the experiment Aim of experiment I am going to carry out an experiment to find a relationship between the incident angle and the refracted angle when light is shone through a rectangular Perspex block. Equipment used For this experiment I will need: * A light box. * A light slit. * A rectangular Perspex block. * A power pack. * A protractor.
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The aim of this experiment is to investigate the relationship between the length of a closed tube and the frequency of the lowest fundamental note.
This is the fundamental note, the lowest and loudest note possible at a certain frequency. It is produced by a standing wave being setup in the tube, these occur when the outgoing wave, and the wave that is returning from the end of the tube mirror each other and for this to happen the wave has to be reflected at the right point in its wavelength. Fair test: To try and keep this experiment fair the only equipment that will be changed is the ones that control the two variables - the signal generator controlling the frequency and the position of the tube controlling the length.
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Diamond has a very high refractive index this is responsible for it having such a aparkle. Apparatus Lab pack D-block Ray Box Glass lens Collimator Prediction I Predict that the speed of light in Perspex multiplied by the refractive index of Perspex (1.49) will equal the speed of light in air. I am able to draw up a triangle formula for my prediction. (fig 1) But in our experiment we are shining the ray onto the curved surface and seeing how light goes from Perspex into air so we will attempt to work out sin I over Sin R and multiply it by the speed of light in air to get the speed of light in Perspex.
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This force can be attractive and repulsive. If an electric current flows through a coil of wire a magnetic field is formed around the coil creating an electromagnet. This is a magnet which can be switched on and off. Here is a diagram which shows the magnetic fields around one turn of a coil To carry out this investigation I will follow the following steps: Insulated copper wire was coiled around a metal nail to make turns and then inserted into a power supply box.
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Turn on your electromagnet and pick up as many filings it will hold. 4. Keeping the electromagnet on, move it over to the weighed paper and turn the power off- the filings will fall onto the weighed paper. 5. Reweigh the paper and calculate the mass of the filings picked up, by subtracting the mass of the paper. Investigating the number of turns on the strength of the electromagnet, this experiment is to find out more about the effect of number of turns on electromagnetism.
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Once the refracted ray disappears, the angle of incidence is the critical angle. You should start seeing a reflected ray coming out of the plastic block as shown above. 4. Plot points on the paper to show the light rays. Connect the points to form lines. 5. Draw normal on the paper between the incident ray and reflected ray as shown. Measure angle i (angle of incidence, critical angle) 6. Repeat step 3 to 5 at least 3 times to get sufficient results. Snell's Law method: 1. Set up the apparatus as shown.
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In addition, smaller whales have a broader range from which they can hear from 10 up to 300Hz. (Unknown2, 2002) Whales depend on sound for communication, navigation, and even detection of predators and prey. The seismic-generated sound waves may disturb critical abilities. Disruption of any of their vital functions can significantly disturb the fitness of whales. (Unknown3) There are many factors that affect the communication abilities of the whales. Temperature and pressure variations found at the varying depths of the oceans can act as voice tubes and channel whale calls further than usual, which allows for whales on the other side of the ocean to hear the calls.
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Find a relationship between the angles of incidence and the angles of refraction by obtaining a set of readings for the angles of incidence and refraction as a light ray passes from air into perspex.
light is entering, sin 2 is the is the incident angle between the light ray and the normal to the medium to medium interface, sin 1 is the refractive angle between the light ray and the normal to the medium to medium interface. Definitions: Angle of incidence: The angle made between an incident ray and the normal to the surface that it strikes. Angle of refraction: The angle made between the reflected ray and the normal to the surface that it strikes.
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Measure how the number of coils of insulated wire around the iron nail effects the amount of paper clips attracted to the electromagnet.
I believe that when more coils are added, the strength of the magnet will increase therefore it will be able to attract more paper clips. I believe this will happen because as more coils are wrapped around the core, the magnetic field gets stronger and stronger. For this investigation I will be changing the amount of coils to increase the magnetic fields strength. I will increase the amount of coils by 5 for every experiment. I will start with 5 coils of wire, then move onto 10, 15 etc up to 45.
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The electromagnet will become stronger if we add more coils because this is generating more field lines over a wider area compared to a straight piece of wire. Method 1. Connect everything together and put the voltage on the power pack to 4V 2. Wrap the coil around the iron nail 10 times and turn the power supply on 3. See how many paper clips it picks up then turn the power pack off 4. Count how many paperclips it has picked up and record in a table 5.
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See RED SHIFT. Scientists also use light to identify and study chemical substances. In addition, light is used for communication. Optical cables transmit information in the form of light over long distances. They are increasingly replacing the copper wires used by telephone companies. Scientists are now experimenting with light as a carrier of information inside very fast central processors of computers. See FIBRE OPTICS. What is light? This question has been a puzzle for centuries. People once thought light was something that travelled from a person's eyes to an object and then back again.
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Investigating the factors which affect the sideways displacement of a light ray through a glass block.
5)Pencil (with a sharp point for grater accurately when plotting points and drawing lines) 6)Piece of white paper Diagram1: Experiment method: As shown in the diagram: I am going to place the glass block on a white piece of paper. I am going to draw around the glass block with the sharp pencil. On the paper I am also going to draw a normal (line 90 degrees to the glass block). By the help of the large-scaled compass, I am going to measure and then draw on the piece of paper 8 lines going from 10 to 80 degrees from the normal creating 8 different angles of incidence.
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A reflective layer is then applied to the surface of the polycarbonate using a process called sputtering. This is a shiny layer that is used to bounce the laser beam back to its original source. This means that this layer must have a very high integrity so that it remains in shape and not break apart. This reflective layer is usually made up of silver, but on occasions it is made up of gold or platinum. With a CD-R and CD-RW there is an extra photosensitive layer, this layer is very sensitive to different frequencies.
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The purpose of this experiment is to understand the law of reflection using the simplest way to see the phenomenon.
(see figure 1) When light is reflected on a polished and smooth surface such as a mirror, an image is produced, which appears to be at the same distance as the source of light. (see figure 2) My hypothesis for this experiment is that we will be able to see the basic laws of reflections being applied when shooting the light to a plane surface mirror and that the angle of incidence will equal the reflected ray. Experimental Method: The way that this experiment will serve its purpose is by using a mirror and the appropriate equipment to observe the law of reflection of light being applied.
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> I will also repeat the whole experiment once more for fairness. DIAGRAM: Method I will take the iron nail and wind the wire around it, leaving the two ends of the wire free. Sorbh Bhushan I will Clamp up the nail and plug two crocodile clip leads into the Power pack and attach each crocodile clip to a different end of the wire, which is wound around the nail. I will turn on the power to the required voltage and then put the paper clip up so that they are touching the iron nail.
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�0 - �40 �40.01 - �80 �80.01 - �120 �120.01 - �160 �160.01 - �200 �200 > 5) How long does your journey take? 0 - 20 minutes 21 - 40 minutes 41 - 60 minutes 60 minutes > Group Tally Frequency Mid point Frequency x Mid point �0 - �40 0 20 20 �40.01 - 80 l l 2 60 120 �80.01 - �120 l l l 3 100 300 �120.01 - �160 l l l l l l l l l l l l 15 140 2100 �160.01 - �200 l l l l l l l l l l l l l l l l 20 180 360 �200 > 0 220 220 40 3120 Mean = Total (Mid Point x Frequency)
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a and refraction ? b and the refractive indices na and nb of the media are related through what has become known as Snell's Law: Equation na Sin ? a = nb Sin ? b Prediction My first prediction is that the angle of incidence will be 2/3 of the angle of refraction. This is because sin I divided sin r is the refractive index, which should be 0.66. Also to back up my prediction I did a preliminary experiment, but instead we put the ray of light through the flat surface of the D-block.
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