International Baccalaureate: Physics
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 Marked by Teachers essays 2

Telescopes  science research project.
In 1655 Christiaan Huygenswere did build powered but clumsy telescope with joined eyepieces. Isaac Newton is honored as the creator of the first realworld reflector in 1668. In 1672 Laurent Cassegrain explained the structure of a reflector having a little convex glass for reflecting the light within a center hole in the primary glass. [2] Figure 1: Telescopes There are some of the currently used Telescopes such as Large Binocular Telescope and Gran Telescopio Canarias. Large Binocular Telescope (LBT) An optical Telescope as Large Binocular Telescope (LBT)
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Incandescent 100 watt light bulb ban: A bright Idea ?
Out of these, only the halogen, fluorescent, CFL and LED lamps are well known. I say this because most of the many sources I searched hardly mentioned highintensity discharge lamps and lowpressure sodium lamps. Given the different types of bulbs that there are, one might wonder why people don't buy the more efficient light bulbs. The simple and perhaps only reason is that the other light bulbs are not as cheap as an incandescent bulbs. That is, incandescents cost way less than any other option.
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Finding the Spring Constant
?T= equipment error + reaction error Example 1: To obtain the uncertainties for time, the average needs to be found out using the following formula: Average = sum of values = 3.81 + 3.63 + 3.74 = 3.73s number 3 To find the uncertainty for time, the biggest difference (regardless of whether it's the maximum or minimum value) needs to be taken away from the average. 3.81  3.73 = 0.08 3.73 3.63 = 0.10s So we use � 0.10s for the first mass.
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Physics IA motion
� 100. * Percentage Deviation =( Exp Value  Accepted Value) / Accepted Value X 100% Apparatus: * Hot wheels radar gun * Video recording device (mobile phone) * Markers (shoes) * Car Equipment: * Chalk * Measuring Tape Diagram: The set up for the radar gun experiment Procedure: 1. A distance of 10m was measured out and marked with chalk. 2. Three markers were used to mark out the distances of 0m, 5m, and 10m. 3. The radar guns settings were changed to 1:1 and km/h.
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Pendulum Lab
Using a ruler for increased accuracy the string length was kept as consistent as possible. Air Resistance The amount of air resistance could have been altered by movement, talking, and other changes such as opening and closing the door. These instances could change the flow of air, which could affect the path of motion by the pendulum and change the period. This was kept to a minimum as the room was closed for the most part during the experiment and had no windows, and motion was kept to a minimum. Type of string The type of string could affect how the pendulum swung due to its weight and thickness, the type of string was kept constant during our experiment.
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IB Specific Heat Capacity Lab
* Specific heat capacity of water = 4182 Jkg1K1 * Specific heat capacity of calorimeter = 385 Jkg1K1. HYPOTHESIS: Increase in the temperature of Water Bath will result in the increase of the total heat gained by water and calorimeter and vice versa. Heat gained by Water and Calorimeter Initial temperature of Solid (Bob) Temperature of Water Bath Assuming that the Equation of Thermal Equilibrium holds true and that no heat is lost to the environment the specific heat capacity of the solid can be calculated by: * MB � CB (T3  T2) = (Mw � Cw (T2  T1))
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Aim: To investigate the relationship between the angle of a slope incline and the acceleration of a model cart moving down it
do not cancel out. We know that force is equal to mass times acceleration (F = ma) and in this case the force of friction is opposite to the remainder of the force of gravity. F = ma = mg � sine ?  Friction Friction is often defined as a coefficient times the reaction force, (u�R) and we know previously from our examination of the Y axis what R really is, so we have: F = ma = mg � sin ?  u�R = mg � sin ?  u � mg � cosine ?
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Oscillating Mass
this load does not exceed the elastic limit: By equating the above two equations, we have: We also know that , where is the period of the oscillating mass. Solving for T, we are able to find: From the above formula, I predict that the only factors which could affect the period T of an oscillating mass are the mass m of the oscillating object, and the spring constant k. If k is kept constant, and m is increased, then the period of oscillation T will also increase, and the oscillating mass is slowed down.
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The Affect of Mass on the Period
Therefore, both controlled variables could conceivably affect the period of the pendulum. If our hypothesis is correct, then the period of the pendulum will have an inverse response to the mass, meaning that as the mass increases, the period of the pendulum should decrease. The materials utilized in our experiment are listed in bullets below and set up according to the following diagram: > Premeasured 20 gram mass > Premeasured 50 gram mass > Premeasured 100 gram mass > Premeasured 200 gram mass > Premeasured 250 gram mass > "Light" string (34cm)
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The Affect of Mass on the Time It Takes an Object To Fall
It is important that the density of the surrounding air remain the same because if it were to change, the amount of air resistance that the helicopter encounters would also change. For example, if the density of the air were lessened, then the helicopter rotors would not push up on as much air causing the air resistance to lessen. If our hypothesis is correct, the mass and the time will have an inverse relationship, meaning that as the mass increases the time it takes the helicopter to fall to the floor will decrease.
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Factors affecting an electromagnet
As with all other physics concepts, there is a calculation involved. The strength of the electromagnet can be obtained through the formula: B = (�NI)/ L. In this equation, B is the value for the strength of the magnetic field in Tesla (T), � is a constant which has a value of (4? x 107), N represents the number of turns the wire has on the nail, I is the amount of current that is passing through the wire, and L is the length of the nail used.
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Movement  modelling the height jumped by horses in the Olympics
And if I also double the height at which the ball is released, then the maximum height it reaches also will be four times greater. I think this because the point at which the ball is released directly affects the speed/velocity and the maximum height it reaches. I also think this because of the use of the Kinetic Energy formula, that when the point at which the ball is released doubles, then the velocity is squared and also doubles, which makes the velocity and the maximum height it reaches, four times greater. Therefore, height is proportional to velocity squared (v2).
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uncertainties with marbles
5.2 4.8 4.6 �0.05 5 4.9 5.3 5.5 5.0 4.4 4.4 �0.05 Average 5.0 5.1 5.3 5.2 5.4 4.9 �0.05 The outliers from the results I got. This is measured in cm by using string, since we can't measure diameter with string, this is how we find out diameter. Diameter=Circumference/ The reason why we can't use the string to measure the diameter of a marble is because don't know where half of a marble is. To find the diameter we first measured the circumference by using strings and measured it in ruler and then divided it by to get the diameter.
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Pendulum work out the value of acceleration due to gravity (g), by using the principle of kinematics of simple harmonic motion of a simple pendulum.
The length of the pendulum would include the length of the string as well as the diameter of the mass bob and the length of the hook as well. When the pendulum suspended from a stand is set into oscillation the time periods 'T' of the oscillations of different lengths 'l' will help us in determining the value of "g". As the length of the string is increased, the time period of the oscillations will also increase but the value of 'g' will not as it is constant for a place always.
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Determination of Coefficient of Friction
should be �0.05N, but I decided to take this uncertainty as �0.1N as it was hard to determine the friction force correctly. I needed to pull the block with the weights at just that force to overcome the friction. I needed to pull equally and using the constant force. It was hard to do, so I decided to add some further uncertainty. Data processing: When determining the kinetic friction coefficient the mg is equal to the normal force. In each situation I add the weight of the block with weight of the number of weights added.
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Investigating resistors
Connect the circuit as chosen 2. Set power supply to 3 v and measure the potential difference and current in the circuit 3. Change the supplied voltage to 6, 9, and 12 v and measure potential difference and current 4. Repeat the above for some trials EM6: parallel EM6: series EM7: EM6: * Resistors in series 1. Set up all materials as shown in diagram 2. Connect a circuit with one unknown resistor, ampere meter, and volt meter and power supply.
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Centripetal Force
 The small of soft mass (rubber stopper)  horizontal string length Apparatus: Name Quantity Accuracy Thin plastic tube about 15 cm long, with no sharp edges 1 �0.5cm 1.5 of fishing line 1  Paper clip 1  Small soft mass (rubber stopper) 1  Mass carrier and slotted masses (10 g each) As needed  Stop watch 1 ?t �0.005s Metre ruler 1 ?l � 0.5 cm Electronic Scale 1 ?m � 0.005 g Method: 1. Securely tie one end of the fishing line to a small, soft mass.
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Light Intensity Investigation
Due to this, increasing distance ultimately decreases the illuminance (how much light from a source hits a specific object) and thus, the light intensity. VARIABLES The independent variable (the variable being changed): The independent variable is going to be the distance between the light sensor and the light source (cm) with measurements varying from 10cm100cm and increasing at 10cm increments. We will do this in order to see the effects varying distance has on light intensity. The variable will be altered by increasing the distance between the two objects by 10cm (interval length) for each set of trials. We will measure and change this gap by using a metre ruler to determine the exact distance and then we will place the light source at one end and the sensor at the determined mark on the ruler.
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Investigation into the relationship between acceleration and the angle of free fall downhill
A brick was set under one of the wooden ramp?s ends, leaving the other end touching the ground. The length (adjacent side to the angle) was measured with a ruler and was then recorded, which would be 59.8 cm for all trials. 2. Another brick was set in front of the other end of the wooden ramp. At the same time, the height of the plane was recorded, noting that the ramp already had a height of 2 cm. This value was then subtracted from the total height, to obtain the original height, which was then recorded 3.
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Researching water turbine designs.
In case of an emergency stop of the turbine (e.g. in case of load rejection), the jet may be diverted by a deflector so that it does not impinge on the buckets and the runner cannot reach runaway speed. In this way the needle valve can be closed very slowly, so that overpressure surge in the pipeline is kept to an acceptable level (max 1.15 static pressure). As any kinetic energy leaving the runner is lost, the buckets are designed to keep exit velocities to a minimum. One or two jet Pelton turbines can have horizontal or vertical axis, as shown in figure 6.5.
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IB Specific Heat Lab
A student’s overall success in this lab will be measured not by the calculated data being accurate but rather in the calculations showing an understanding of the manipulation of the formula Q=mcâT and its uncertainties. This lab will bring a real world application to this concept and give students hands on experience with specific heat. ASPECT 2: Controlling Variables: 1. Constant temperature (100° C) of the metals that we are using to find their specific heats. 2. Same scale and thermometer used for measurements 3.
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Experiment to show the application of Kirchhoffs Voltage Law & Kirchhoffs Current Law in series, parallel and combination circuits.
Also for current to flow either in or out of a node a closed circuit path must exist. We can use Kirchoff's current law when analyzing parallel circuits. Kirchoff?s second law that is KVL states that in any closed loop network, the total voltage around the loop is equal to the sum of all the voltage drops within the same loop which is also equal to zero. In other words the algebraic sum of all voltages within the loop must be equal to zero.
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Investigating the Oscillations of an Obstructed Pendulum
Dependent Variable: The time period of one oscillation Control Variables: 1. Mass and properties of the bob being used 2. Angle of displacement (10°) 3. Mass and physical properties of the string being used 4. Positioning and location of the stand 5. The orientation of the obstruction 6. Room conditions Apparatus: 1. 1 stand to which the spring, the bob, and the obstruction will be attached 2. 1 bob of mass 100g 3. 1 string 4. 1 wooden rod of approximately 15cm length (obstruction) 5. 1 stopwatch 6. 1 metre ruler Risk Assessment: 1.
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