physics essay and lab report

1.essay

Make sure you give a complete answer to the question including details, examples and supports.  These essays should be good full paragraphs with explanations as they are worth 20 points each.  You might want to answer the questions in a word processing document and then copy and paste the two essays into the text box and submit.  I will grade the essays and give you feedback on your responses. The two essays are:

1. A can of diet soda floats in water, whereas a can of regular soda sinks. Explain this phenomenon in terms of density and in terms of weight versus buoyant force. Support your answer.

1. A 10 kg iron ball is dropped onto the pavement from a height of 100 m. If half of the heat generated goes into warming the ball, find the temperature increase of the ball. The specific heat capacity of the ball is 450 J/kg•Co. Explain why the answer is the same for a ball of any mass. Show your work please.

2.lab report

This laboratory activity uses calorimetry to find the specific heat of an unknown metal. The amount of heat transferred between objects of different temperatures depends on three basic factors: (1) the mass of the objects, (2) what the objects are made of, and (3) the temperature difference between the objects. The basic assumption when performing calorimetry is that the heat lost by one object equals the heat gained by the other object. In reality, some heat will be lost to the surroundings, but this is often ignored.

Procedures

1. 1. Stack two Styrofoam cups together. This will reduce heat lost to the surroundings. Create a lid to the calorimeter by cutting the rim off one of the Styrofoam cups. You can cut a hole in the top of the lid or cut away part of the side of your lid so the thermometer can slide into your calorimeter without losing too much heat to the surroundings. (See below.)

1. 1. Bind together the nails provided in your lab kit with the included rubber band. Suspend the nails from your spring scale, and record the mass of the nails in units of grams.
   2. Add enough water to a small saucepan to cover the nails (still bound with the rubber band) so that when you add them to the water later, the nails are completely submerged. Bring the water to a boil.
   3. Use tongs to place the nails (still bound together with a rubber band) into the boiling water. Let the sample boil for at least 5 minutes. You may assume the temperature of the nails equals the temperature of the boiling water (approximately 100 °C with some variation for elevation).
   4. Use the 50-ml graduated cylinder to place 100 ml of room-temperature water into the Styrofoam cup calorimeter. (Remember the density of water is approximately 1 g/ml, so the mass of the water in the calorimeter is 100 g.)
   5. Measure the temperature of the water in your calorimeter to the nearest degree. (Be sure to measure in degrees Celsius.)
   6. Use tongs to transfer the nails from the boiling water to the Styrofoam calorimeter and quickly place the lid on top. Stir the water in the cup with the thermometer (very gently so the thermometer doesn't break). Record the highest temperature the water reaches. (Make sure the temperature is no longer rising before you record the data.)
   7. Use the principle that the heat lost by the metal equals the heat gained by the water in the calorimeter to find the specific heat of the nails.

Repeat the experiment two more times and average the values obtained.

1. Answer the following analysis questions:
   1. How would doubling the number of iron nails used in this lab affect the overall lab results? Explain.
   2. A student heats equal masses of iron (c = 0.45 J/g-C) and aluminum (c = 0.90 J/g-C) to the same temperature and then places the metals into separate beakers along with 50 ml of room-temperature water. Which beaker will have the highest final temperature? Explain.
2. Write a formal lab report. The report should include the answers to the analysis questions along with the formal lab report elements PDF.