Trenton Gravity project

Colorado Online @ Astronomy 1110 Lab 6 A STRONOMY 1110 L AB 6: G RAVITY Measuring Gravity In this section, you’ll measure the influence of the Earth’s gravity on different objects. 1. In the table below, list your three objects in order of decreasing mass (most massive first). a. Take a photo of your objects, with your Student Information card, and insert it below. 2. Predict which object should fall fastest and which should fall slowest from your list. Explain your reasoning. In the past, before I studied science, I would have guessed the flip flop would fall the fastest due to it’s larger mass. I have learned previous to this experiment that mass does not determine the speed at which an object will fall and fully expect all objects to fall at the same rate, not accounting for human error. Object Name Trial 1 Trial 2 Trial 3 Average Expo Marker .35 seconds .31 seconds .36 seconds .34 seconds Bottle Cleaner .38 seconds .33 seconds .44 seconds .38 seconds Flip Flop .38 seconds .43 seconds .40 seconds .40 seconds  Using your ruler or meter stick, find a position 1 meter above the floor. o If you are using a ruler, you may wish to use clear tape to mark a location on your wall. o Be careful when removing your tape. o Take a photo of your set up, with your Student Information card, and insert it below. 3. Once you have found a spot one meter above the floor, drop each object and time how long it takes to hit the ground using your stopwatch. Record your result in the column labeled “Trial 1”. Repeat the experiment two more times. 4. Repeat the experiment in #2 for your two remaining objects. 5. Calculate the average of the three trials for each object to find the average falling time for that object. Record the result in the appropriate column of the data table. 6. Do the average falling times you calculated match your predictions in #2? Why or why not? I believe the average falling times I calculated match my predictions in #2. This is a small drop so a lot of human error can occur but the average times of each objects happen within .06 seconds at most which is about the same fall time for each object. 7. Predict how the falling time of a piece of paper should compare to the results you measured in your table. Paper should fall slower than the objects measured in my table because the shape and material of the paper will cause it to float on its way down. Page 1

Colorado Online @ Astronomy 1110 Lab 6 Trial 1 Trial 2 Trial 3 Average Flat 1.7 seconds 1.3 seconds 1.38 seconds 1.46 seconds Crumpled .46 seconds .41 seconds .46 seconds .44 seconds 8. Why does the paper fall faster when it is crumpled compared to when it is flat? The paper falls faster when it is crumpled compared to when it is flat because the flat paper meets air resistance and floats down slowly, the crumpled paper does not have the same air resistance so it falls faster. 9. How does the falling time of the crumpled paper compare with the falling times of your three objects in the previous table? The falling time of the crumpled paper compares better with the falling time of the three objects than with a flat piece of paper. The falling time was .1 second slower than the falling time of the fastest falling time object. 10. There is no air on the Moon. How would the falling time of a flat paper compare to a hammer if you dropped both of them on the Moon? When there is no air resistance the falling time of flat paper should be the same as the hammer if these objects were dropped on the Moon. Conservation of Energy The concept of “energy” is an incredibly useful tool for scientists. Simply put, energy is the ability of an object to alter its environment. Energy considerations can dramatically simplify the analysis of many scenarios, especially events that include rapidly-varying forces. Energy comes in two basic forms, kinetic and potential. Kinetic energy is carried by objects in motion. This can include a flying baseball or a car in motion, but it also includes the thermal energy (heat) carried by the motions of atoms in a fluid. Potential energy is energy in waiting. Under the right circumstances, potential energy can turn into kinetic energy. For example, a roller coaster at the top of a hill carries a lot of potential energy due to its position above the ground. Objects that feel the force of gravity carry more potential energy as they get farther away from the source of gravity. That’s why a taller roller coaster is more fun (or more terrifying!). Energy is useful because it is conserved. That means that energy is not created or destroyed. It merely changes form from one type of energy to another. In this exercise, you will observe the conservation of energy and see how it changes from one form to another. In this section, you’ll use recordings of the Skate Park Simulator from PhET to explore and quantify the connection between energy of motion and energy of position. This simulator runs in any modern browser. While not necessary for this lab, you should feel free to play around with the simulator. Page 2

Colorado Online @ Astronomy 1110 Lab 6 14. Did your predictions in 13a) and 13b) match the behavior of the skater? Why or why not? My predictions above matched the behavior of the skater because of observations made at skate parks previously. The absence of friction allows for the skater to reach the same free fall maximum heights. Orbits We’ve learned about Kepler’s Laws and how they can be used to describe the motions of planets within our solar system. Let’s try to connect the motions of the planets to what you’ve learned about Newton’s Laws and gravity. Figure 3: The Moon's orbit around the Earth. Adapted from original images by NASA. 15. The image in Figure 3 shows a schematic of the Moon’s orbit around the Earth. Imagine the Moon is moving in the direction indicated by the arrow. In the absence of a force acting on the Moon, how will it behave? If there is an absence of a force on the moon the moon will continue up and continue straight and break its normal orbit from the Earth. 16. What force is responsible for keeping the Moon in orbit around the Earth? (use full sentence) Gravity is the force responsible for keeping the Moon in orbit around the Earth. Page 4

Colorado Online @ Astronomy 1110 Lab 6 Figure 4: A highly-elliptical orbit. The yellow circle marks the location of the Sun, which is off-center at one focus of the ellipse. (Adapted from original work by NAAP Labs) 17. Use what you know about Kepler’s Second Law to rank the speed of motion of the planet at points A, B, and C in order of increasing speed (slowest location first). The planet at point C will be the slowest speed, the planet will be moving faster at point B, and finally at point A the planet will be moving the fastest of all the other points. 18. At which location in Figure 4 is the potential energy of the planet greatest? At which point is potential energy smallest? At point C potential energy of the planet is the greatest and potential energy is smallest at point A. 19. Use conservation of energy arguments to explain why the results of #19 and #20 are different. How are the two rankings connected to one another? The results of 19 and 20 differ due to the constant of mechanical energy. An object further away from the sun will have a greater potential energy but a smaller kinetic energy. An object closer to the sun will have a greater kinetic energy but a smaller potential energy but both planets will contain the same mechanical energy. Page 5