Marble Investigation Lab

Design:

            Our aim was to investigate the effect of the mass of the marbles on the distance that the car travels. For this investigation, we had to think of the variables, so we can control some of them and to see what will affect what. We deduce that the independent variable would be the mass of each marble. And the dependent variable, the one that will change because of the mass of the marbles, was the distance that the car will travel. The control variables were the distance of the ruler, the slope and the height of each book. The materials that was needed to make this investigation were: 5 books, 3 big ones like the chemistry one, and 2 small ones like the our science Motion book; 2 one-meter rulers, so we can make them as a slope for the marbles; one car, that has the wheels with very little friction; one plastic cup, so we can put it on top of the car; tape, to place the plastic cup; 4 different marbles, each one with a different mass, (our marbles were: normal marble with 17. 880g, small marble with 9. 680g, a normal metal marble with 28. 370g, and a small metal marble with 21. 750g.); and a ruler to measure that distance that the car will travel.

            The Procedures we had to do for the investigation were the following:

• 1.     Put the three big books and one small book, so the height must be 14 cm.
• 2.     Put one big book and one small book on the opposite side, so that it can have the height of 6 cm.
• 3.     Place the two rulers on top of the books so they can stay parallel to each other.
• 4.     Let a gap of about 1. 5 mm between both rulers.
• 5.     Design a slope with the rulers.
• 6.     Place the rolling car with the cup taped on top of it next to the small pile of books.
• 7.     Start with your first marble.
• 8.     Place the marble on top of the ruler and let it go.
• 9.     Let the marble enter the cup on top of the car.
• 10. See how far the car keeps going.
• 11. Measure the distance between the pile of small books and the car.
• 12. Do these steps for all the marbles you have (4). And for each marble, you should do 3 trials.
• 13. Record the distance for each trial of each marble.
• 14. When you are finished with your data table, get the average distance for each marble.

Data Collection and Processing:

            Some errors that I observed in the investigation were the space between both rulers and the fact that at some trials, the marble would come out of the cup.

            For the first error, the rulers had to be in a certain distance away from each other, so the marble would roll down easily and wont keep wiggling. We had to put 2 one-meter rulers to form the slope. We tried putting both rulers together, but the marble would come out of the ruler before getting to the bottom. So, we decided to put a little gap between both rulers, that way the marble will keep in the right place until the bottom. We didn’t measure the gap to see how many cm they had to be far away from each other. The error must had occurred in the gaps, because if the gap was bigger on the top an on the bottom it got smaller, than the marble would have gained more speed as it goes down. We should have made the gap exactly the same from the top to the bottom of the slope.

            For the second error that we observed, we tried the first trial with the normal marble. On the second trial, we saw that the marble wouldn’t stay inside the cup. It would hit the end of the plastic cup and fall out. The distances for those first trials were different. When the marble stayed inside the cup for the first trial, the distance that the car traveled was less than when the marble got out of the cup on the second trial. What may have caused this was that when the marble hits the end of the cup and stays inside the cup, the car has more weight (don’t forget, the car has really low friction wheels, so any force will cause it to move).  When the marble hits the end of the cup and falls out of it, the car will only have the weight of the cup and the force applied from the marble in movement. This may had caused some differences in the data collected.

           

Data Table and Graph

 This is our data table, which contains the marble type, their mass, the number of the trail and the distance travelled in this trial.                                           

Marble	Mass	Trial	Distance Traveled (cm)
Normal Marble	17,880g	1	41
Normal Marble		2	39
Normal Marble		3	43,5
Small Marble	9,680g	1	4
Small Marble		2	4
Small Marble		3	6
Metal Big Marble	28,370g	1	42
Metal Big Marble		2	51
Metal Big Marble		3	40
Metal Small Marble	21,759g	1	19
Metal Small Marble		2	13
Metal Small Marble		3	19

When we were done with collecting the data, we got the average distance for each marble

Marble	Average Distance Traveled (cm)
Normal Marble	41,16
Small Marble	6,66
Metal Big Marble	44,33
Metal Small Marble	38,33

                           

We also did a bar graph to explain in a more visual way in which the marble’s mass affected the distance.

 

 
 Conclusion and Evaluation:

            Our conclusion for this investigation is that the less mass the marble or any object has, the less is the distance that the car will travel, and the more mass you have the more distance the car will travel. That makes us go back to our aim, which is the effect that mass of each marble on the distance that the car will travel. When we tried the metal big marble, which has 28.370g, the distance for each trial was above 40 cm. When we tried the small normal, which has the mass of 9.682g, the distance traveled didn’t even pass 8 cm. We concluded that the less denser the object is, the less momentum it has to make something move or stop, and the more mass the object has, the more momentum is needed to stop something or make it move.

            As I mentioned on the last post, the possible errors that may had occurred during the investigation were the gap between the ruler of the slope and the marble getting out of the cup after hitting the end of it. Those two possible errors may have caused some outliers in our data. For example, for the small marble, the first 2 trials were exactly the same because the marble stayed inside the plastic cup. On the third and last trial, the marble “popped” out of the plastic cup, making the cup go 2 cm more than the last two trials.

            One way to eliminate those errors would be measuring the distance of the gap between both rulers (of the slope), so that the marble won’t gain or loose acceleration. And for the other error there is no solution. But as an improvement, we could redo de trial where the marble popped out of the plastic cup, or redo the trial where the marble stayed inside the plastic cup. There is no logical way to prevent the marble of popping out of the cup, but we could redo the trials. That would eliminate the outliers on the data collected. 

What was the purpose of these first two days of science class and what are my plans for this year?

My plan for this year is to keep focused on my work and try to pass the year with good grades, so i can start the next year (10th grade) with the right foot. The purpose of those two days of class was to introduce us to our next units and to show us that in science you cant give up on something just because it is difficult. We have to believe in ourselves so we can succeed in our science class.