Name: Anushka Aritri Rahman
Grade: 9-B
Title:
Does a large swimmer make a bigger splash when they hit the water just
because they are bigger, or is it because they were moving faster?
Aim:
To find out whether it is the mass of a person that affects the impact involved
(in this case, the splash) or the speed of the person.
Hypothesis:
Predictions related to this investigation are:
I predict that a bigger swimmer is making a bigger splash because of the
weight of the swimmer.
Based on my first assumption, I also predict that the larger the swimmer is in
size and mass, the faster its average speeds shall be.
Scientific Reasons:
A large object is likely to have smaller/faster average speed.
Key variables:
There are three types of variables. They are:
I.
II.
III.
Independent Variable.
Dependent Variable
Controlled Variable.
I. The independent variable is the object or substance that I control or test. In
this case, the independent variables is:
a) The mass of the ball bearings
II. The dependent variable is the substance(s) that is affected, in either
measurement or features. In this case, the dependent variable is:
a) Speed of the bearings
III. The controlled variable is the substance(s) and object(s) that will not
change. In this case, the controlled variables are:
a. Chemical Balance
Name: Anushka Aritri Rahman
b.
c.
d.
e.
Grade: 9-B
3 one-meter rulers
Stopwatch
Clamp
The height of the ramp-19cm
Apparatus/materials used:
The materials that I have used for this experiment are:







Ramp
5 metal ball bearings (different sizes)
3 one-metre rulers
1 Stopwatch
Chemical balance
Clamp
Blue tack
Method/Procedure Used For This Experiment:
Pre-experiment…
First, I chose which ball bearings that I was going to use for this experiment. I
was careful about making sure I had every size of ball bearings that were
available.
Then, I had to take some measurements before I could start the actual
experiment. I had to measure the accurate mass of each of the ball bearings
that I was going to use for this experiment.
I then set up the apparatus, and made sure that everything was secure. I fixed
the ramp at a set position using a clamp, and raised it 19 centimetres above
the floor (I was working on the floor). I fixed two rulers onto the ramp to form
a path for the ball bearing to use as a guide. I used blue tack to fix it on. I even
stuck 5 tiny bits of blue tack onto the floor so that the ball bearings would be
secure while the experiment was in progress.
During the experiment…
I started with the biggest ball bearing and worked my way chronologically
down to the smallest (5th Biggest).
For each of the ball bearings I followed the same method. I held the stopwatch
while my partner put the ball bearing at the top of the ramp (the higher end)
and caught it at the end. I measured the amount of time it took for the ball to
travel from the top to the bottom of the ramp. For each ball bearing, this bit of
the experiment was repeated three times for accuracy.
After the experiment…
I had to find the average speed of each of the ball bearings, I had to add all
three measurements and then divide them by three.
Name: Anushka Aritri Rahman
Grade: 9-B
Result Table:
Table: All Data gathered from the Experiment
Ball
Bearing
No.
Mass of the
balls(grams)
Trial 1time in
seconds
Trial 2time in
seconds
Trial 3time in
seconds
Distance
in
meters
Average
time in
seconds
1
27.94
0.97
0.96
0.85
1
0.93
Average
Speed in
meters
per
seconds
1.08
2
16.68
1.31
1.06
1.03
1
1.13
0.88
3
8.97
1.37
1.16
1.19
1
1.24
0.81
4
4.06
1.25
1.28
0.97
1
1.67
0.60
5
0.87
1.03
1.06
1.28
1
1.12
0.89
For example, to get the average speed of Ball Bearing No. 1, I would have to
use this simple formula:
Average Speed= Distance Travelled
Time Taken
Average Speed= 1
0.93
m
s
Average speed= 1.08 m/s
I followed the same method for 2, 3, 4, and 5.
Name: Anushka Aritri Rahman
Grade: 9-B
Data Processing:
Comparison Between the Mass of the Ball Bearings and the Average Speed at which it Falls
y = -0.0068x + 0.9316
R2 = 0.1824
1.2
Average Speed (m/s)
1
0.8
0.6
0.4
0.2
0
0
5
10
15
Mass of Ball Bearing (grams)
20
25
30
Name: Anushka Aritri Rahman
Grade: 9-B
Data Analysis:
The graph that I thought best suited the information given was a correlation
graph. The R squared value tells me that the correlation between the mass and
its speed is very low, and that it does not go through the origin (0,0). However
the graph does show that when the average speed is high, the mass of the ball
bearing is low, and when the average speed is low, the mass of the ball
bearing is high.
Conclusion:
From the data analysis above, I can now conclude that this experiment proves
that my hypotheses are correct (roughly). However, due to unavoidable
inaccuracies during the experiment as well as some limitations (See:
Evaluation of the Procedure), there is still uncertainty as to how much my
hypotheses can be applied in this subject.
Evaluation of the Procedure:
I was able to do the experiment as accurately as possible at the time, and was
able to take all the readings and measurements necessary. The equipments
and apparatus used were all secure during the experiment.
The measurements are likely to be inaccurate because the amount of time that
it took me to start and stop the stopwatch was enough to waste a few
milliseconds. This makes the measurements of data not as reliable as it would
have been with better equipment. I was unable to make a proper line graph
because the masses were inconstant, and that made it had to plot in Ms Excel.
There are many ways to extend this investigation. I could use balls made of
different materials like wood and rubber, and see if there is a difference in
average speed. The weights of the balls have to the same, and it would be
easier to plot graphs and work with them, if it were all real numbers (1, 2, 3, 4,
etc.). This would give us an idea of whether or not it is the material that is
causing the average speed to increase/decrease or the mass.