Polarization
Introduction:
PART ONE: POLARIZATION
Method 1:
Two polarized disks were put into a grooved holder with their polarization axes lined up, and a bright red light emitting diode (LED) was placed on one side, and a light sensor was placed on the other side. Light intensity was measured as a function of the plastic rotating polarizer angle from 0 to 180 degrees. Science Workshop was used to measure the intensity for every 5-degree rotation (Fig 1).
Method 2:
The mineral calcite exhibits birefringence (double refraction), and therefore has two different values for its index of refraction. A calcite crystal was placed on top of print and rotated in order to see the difference between the two rays, the ordinary ray and the extraordinary ray. A polarizer was then used to look at the images formed by the calcite.
Method 3:
In order to determine the stress points in a plastic object, we used a photoelastic effect where we looked at the object through a polarizer. When the plastic was squeezed together, changes in the color occurred, displaying points with greater stress.
Method 4:
Polarization by reflection from a non-metallic surface was used in this method in order to help distinguish the plane of incidence, and Brewster's angle. A cardboard disk with a picture on it and a polarizer were placed in the holder, with a piece of black plastic (n=1.491) in between them. Brewster's angle was determined from tan = n, and =56. We then looked through the polarizer at this angle and were able to determine the polarization direction. We also viewed the reflection of a ceiling light directly above the black plastic in order to determine if it was polarized in this case.
Method 5:
In order to determine polarization by scattering, a jar was filled with water and dried milk, and then a flashlight was shined directly down into the top of the jar. From the side of the jar, we looked through a polarizer at the scattered light. From this we determined if the light was horizontally polarized.
PART TWO: LIGHT MEASUREMENTS
Method 1:
A halogen bulb light source was set up at the end of a yardstick, and a light sensor was set up on the yardstick beginning at 0.1m from the light source. Science Workshop was again used to measure the intensity of light ranging from 0.1m to 1.00m (Fig.
Fluorescence measurement provides very important information about the photochemistry of a particular molecule. The first part of this experiment was dealing with the fluorescence behavior of a Leucophor PAF. Information from both spectrophotometry and fluorimetry was used to measure the quantum yield as well as to explain why Leucophor PAF was use as commercial optical brightener. The second part of this experiment dealing with fluorescence quenching of quinine bisulphate solution (QBS) is the presence of sodium chloride.
There were fears about whether the value of surface strain measured by the strain gages was equal to the genuine distribution of air throughout the cross-section of the legal profession. Cunningham and Goldsmith [6] compared the forces measured by strain gages to those received by piezoelectric quartz crystals embedded between two similar bars. The results indicated excellent understanding between both methods. Krafft et al. [7] were the first to use strain gages in the Split Hopkinson Pressure bar.
The input variable which will be used in this investigation will be the light intensity (this will be a 100Watt bulb being moved closer and further away from the plant). The outcome variable which will change as a result of this experiment will be the amount of oxygen made in the experiment due to the amount of light intensity increases (causing the plant to photosynthesise more).
To continue the experiment further I can use a different source of light to test the intensity of light. For the food coloring experiment, I could use a different food color such as yellow or orange to test.
Opposites attract. James Hilton uses this fact in Goodbye, Mr. Chips to create tension in the story; however, he makes greater use of this polarization to develop the character of Chips. Mr. Chips and Katherine Bridges may be viewed not only as opposites but also as arguments. Hilton uses thesis in the form of young Chips and antithesis in the form of Katherine Bridges to arrive at synthesis, the personality and character of the mature schoolmaster.
light hitting the cell by the ratio of area of the cell to the ratio
Williams, B. 1999. A History of Light and Lighting. [online] Available at: http://www.mts.net/~william5/history/hol.htm [Accessed: 5 Jan 2014].
The hypothesis stated that when the spinach extract was placed on the polar paper chromatography the pigment would separate into different pigments on the...
We then placed several dots as specified by the lab protocols, for instance placing a pencil dot in from the edge. Then, using a capillary, we spotted the 3cm spot about five times with spinach extract, that was obtained in column chromatography. Students, the placed a spinach leaf on the paper, covering 7 and 10cm dots. Using a quarter, students rolled over the leaf from about the 7 to 10cm mark several times. We then rolled the paper into a cylinder and stapled it. Once the paper was placed in a beaker containing 30ml of 90/10 hexanes to acetone mixture, foil was placed on top. Once the solvent reached about 1cm from the top of the paper, we took it out and marked the solvent front and again outlined every spot. We again, measured the distance to the solvent front and to the center of each spot—and calculated the Rf values for each spot. The colors for each spot, for both this and the paper chromatography were
In chemistry, Colorimetry is used a lot. They use it for things such as colour painting, food manufacturing, and textiles. Colorimetry can also be used to measure light. The amount of light absorbed is called and also is measured as the absorbance which is a use of the coloured solute concentration. To use a colorimeter, different kinds of solutions have to be made, this includes a regulator or orientation of identified concentration.
The area under the curve represents the energy required to compensate for the thermal events of the sample. Some instruments represent endothermic processes (melting) as downward curves and exothermic processes (crystallisation) as upwards peaks, while other instruments show it in the opposite way. (18) DSC can be used to evaluate different thermal events including melting, solid-state transitions, crystallization, glass transitions … (19) DSC may therefore be used to differentiate between polymorphs according to their melting point or to examine the transformation of metastable systems. It is essential though to confirm the results of DSC with other characterization techniques such as Raman spectroscopy, IR spectroscopy and X-ray diffraction.
Refraction of Light Aim: To 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. Introduction: Refraction is the bending of a wave when it enters a medium where it's speed is different. The refraction of light when it passes from a fast medium to a slow medium bends the light ray toward the normal to the boundary between the two media. The amount of bending depends on the indices of refraction of the two media and is described quantitatively by Snell's Law. (Refer to diagram below)
Now in order to understand how lights is able to be refracted in different angles, it is important to understand the Snell’s Law which states that, the refractive angle always depend on the refractive index of both media. Now, the refractive index keeps on changing depending on the wavelength of the light passing through. Light, as we know, it is a wave that has different wavelength. Each wavelength represents a different color. Thus, different colors will have different refractive index when passed through the same media. It is important to note that light is normally refracted twice when it travels through a prism, first on its way in, and when it is going back.
The reason light intensity is being used compared to whether or not a plant needs light. It is because The experiment wants to show that the rates of photosynthesis will vary according to how much light from a light bulb will be trapped in. the chloroplasts, in the leaf. The more energy trapped the more efficient a chemical reaction can take place and the speed of photosynthesis will increase. There are many things which can affect the photosynthesis of a plant such as light intensity, temperature and carbon dioxide levels.
type of plastic and by color. The first step is the most important one in the process.