Variables:
Dependent:
Independent:
Controlled:
- The size of the marble
- Gravity
- Flatness of the sand
Scientific Knowledge:
As the size and speed determine the size of the crater created by the impact of the marbles then the following formula must apply to determine the size of the crater:
PE=m x g x h m=Mass g=9.8(gravity) h=Height
Energy is lost through heat being transferred from the speed or velocity due to air resistance so to find out the PE at the point of impact we will have to find out the Kinetic energy:
KE=1/2 x m x V2 m=Mass v=Velocity
So now I know how to work out the PE and KE I can now find out the PE at the point of impact.
So by knowing these formulas I know that the diameters of the craters created by the small marble will be less then the larger marble as they steadily increase as the height increases. As the conditions will be the same. i.e. the gravitational potential energy, room temperature and heights the marble is dropped from.
But this experiment is not mimicking a meteorite crash, as meteorites come in at an angle, at different speeds and in different shapes (not perfectly round), they also don’t land on perfectly flat surfaces, but as I have to investigate the relationship between the mass of the marble and the diameter of the crater.
Prediction:
It is common sense that the higher an item is dropped the more force it will exert when it lands or collides with another object. We can also see this when we bounce a ball from a height of 1 meter it will bounce higher than that of if it was dropped from 0.50 meter. But in the fact of a meteorite hitting earth will not bounce back as a meteorite does not have the same properties as a ball, so when a meteorite will hit the earth it will create a crater. The size of the crater will depend on the size and speed it was traveling at the point of impact. So I am going to predict that the small marble will create a smaller crater compared to the larger marble when dropped from the same height. So the graphs will be something like this:
The top line is the large marble and the bottom is the small marble. This is because the mass in the two marbles is different so the PE is different, less in the smaller one and higher in the larger one. Making the energy transferred different from each other at the point of impact.
The Barringer Meteorite Crater:
The Barringer crater is one of the world best know and most studied Meteorites. It is a gigantic hole in the ground that was formed by a Meteorite crashing into the earth. There is a rim of smashed and jumbled boulders that surround hole, some as high as 150ft. When the meteorite was first discovered the plain around it was covered with chunks of meteoritic iron there was more 30 tons of it found scattered around over an area 8 to 10 miles in diameter. This also shows that there will be a crater formed, and will have a definite rim.
Analysis:
Although a marble does not have the same properties as a Meteorite it was able to model a meteorite. I have found out that my prediction was true as my average graph looks like the following just like I predicted:
This graph shows that a crater is formed when the marble was dropped, but the diameter of the crater depended on the how much potential energy it carried. So the height increased as the diameter of the crater increased. The terminal velocity was not reached as the diameter did not stay constant at any point. The reason that the size of the crater was slowly was that the motion (speed) of the marble was slowly increasing, so that means that the faster the marble is traveling the bigger the crater will be.
The potential energy at point of impact of the large and small marble is:
PE=m x g x h m=Mass g=9.8(gravity) h=Height
To conclude, my results did follow my prediction and prove my scientific knowledge to be true. I know this because the graph I drew in my prediction is exactly the same shape as my final results graph. The graph shows that as the height of the drop increases the diameter increases, but the two are not directly proportional. The table above shows the potential energy at the point of impact, it shows that the potential energy increases directly proportional to the drop height. The marble was able to mimic a real meteorite because it had just the right properties of a meteorite, although it did not have all of the properties, it did have the essential one, it was spherical. As a meteorite is kind of spherical, a marble was able to mimic it. This is because it will create the same type of shape of crater as a real meteorite will do.
There was energy being converted all the way through the experiment, the following will show the energy conversions:
The marble is lifted up
(Giving it GPE)
The ball is dropped
(Giving it gradually increasing
PE)
As the ball falls the friction between
the air and the marble
(Transferring the PE to KE)
Evaluation:
I think that my investigation on went very well, the results I got from my experiment were a good and helped me make my conclusion. My results were collected and tabulated accurately, this was due to the reason that I took each reading three times to ensure we have a n accurate average in the end. We did the experiment accurately as there were three people in group taking doing different jobs, I was measuring the diameter of the crater created, Ali was dropping the ball accurately so it was from the same place as it was on the table and Manminder was tabulating the results and making sure the sand was even. My results had 1 anomalous result, which was for the small marble. I think this may be because I lost my concentration in the experiment and I started to measure the diameters incorrectly. As there was an anomalous result I used the other two results to work out my average for that drop height.
The results I had were not enough to make my conclusion, but I think I could have made my results more accurate by repeating the experiment 5-7 more times for me to form a definite conclusion. There were many ways that I could have improved my results. I could have used laser technology, so that they could calculate the diameter, area or even the perimeter of the crater, I could have used digital cameras to take pictures of the craters and than transferred these pictures on to computer, so that I could then make detailed calculations on the size of the crater. I could have used a device or mechanism that holds a marble at a set height and then lets go of it by applying no force at all. Having these types of instruments will decrease the chance of me getting anomalous results.
As meteorites do not land at direct 90° to the surface I could have also dropped the marble from different directions. The shape of a meteorite will not always be round like the marble, but we could use play dough or little rock/pebbles.
As the meter ruler was not at eye level the dropping height may have been measured inaccurately or even incorrectly. And there may have been inaccuracies when throwing the ball, Ali might have pushed the marble down in some of the trials. And there is a possibility that the sands surface was not even at the time of the impact, which may have needed more energy to create the same diameter when the sand is flat.
