Falling ball (María M, Kristina P, Victor S, Alvaro P)

Falling ball experiment

- Research question: Investigation on how changing the height of a falling ball affects the surface it hits.

- Objective: To investigate how the depth of the marble in the polyacrylate solution changes when there is a change in the vertical height of the free fall, by measuring the distance from the top of the polyacrylate to the bottom of where the marble has sunk.

- Data:

This table shows the results:

Height (cm)	Depth (cm)					Average (cm)
25	1,5	1	1,5	2	1,25	1,45
50	2,5	2	3	2,25	2,5	2,45
100	4	4,5	4,5	5	4,25	4,45
150	5,5	4,5	5	6	5	5,2

Sodium polyacrylate: 5 grams in 250 mL water. 

- Hypothesis: 

Our hypothesis states that when we throw a marble into the Al3B5 solution the height (h)  from which we throw it, will affect the depth of the hole that the marble makes in the solution. Due to gravity, when the marble is thrown from a certain height it will sink into the solution a certain amount. The higher the marble's starting position is, the deeper it will sink, which means that the height of the marble is directly proportional to the depth. For example, we expect that if we throw the marble from 50cm from the solution, it will sink less than when we throw it from 150cm.

There is also a relationship between the height of which the marble is dropped and the energy it releases (kinetic). When the marble is dropped futher away from the solution, the kinetic energy released is bigger. This happens because the higher the marble's starting postion is, the more gravitational energy it has (law of gravity, the gravity pulls the object with a stronger force, increasing it's energy).

KE = 0.5 • m • v2

m = mass of object

v = speed of object

g=9,8m/s2

PE (gravitational) = weight x height

weight= mass x g

- Variables:

Independent: This is the height of the free falling ball  (25, 50, 100, 150, 200 cm), because it's the one which we change. The height was measured using a ruler for the first two numbers (25cm and 50cm), and then a tape measure for the rest.

Dependent: The dependent variable is the depth(cm) of the marble in the polyacrylate, because it's the one which changes depending on the height. This is measured accurately with a ruler, from the top of the solution in the beaker, to the bottom of the marble.

 Controlled: The temperature (Cº), pressure (atm)… Because they are maintained constant. They don't change in the whole experiment. 

  - Method: 

Materials.
Solution
5 marbles
Ruler
Tape Measure
Table
Pencil
Beaker

1. Prepare the solution. Put 5 grams of polyacrylate into a beaker, and add 250 mL of water. Mix until the solution has a jelly-like consistency.

2. Prepare the marbles. Pick out 5 marbles which have the same size and weight.

3. Measure out the distance. Using a ruler or a tape measure the distance. Then, hold the marble at the chosen height.

4. Drop the marble. You must drop the marble 5 times at a given height, and measure the depth from the top of the solution in the beaker to the bottom of the marble.

5. Repeat step 3 and 4 with all the heights chosen.

6. Record the data. Find out the average depth of the marble in the solution.

7. Wash and put away all of the materials used.

Conclusion:  We have discovered that the height from which the marble is dropped affects the depth the marble sinks into the polyacrylate. As we said in the hypothesis, they are directly proportional, which means that when the independent variable (height of the starting position) increases, the dependent one (depth of the marble in the solution) also increases. As we can infer from the results (the table) there IS a relationship with the formula of kinetic energy (the higher the starting position is, the more kinetic energy the marble has) and gravitational energy (the higher the marble is, it is pulled with more gravitational force, increasing its energy). Both formulas are proved to be valid.

- References:

Hyperphysics.phy-astr.gsu.edu, (2014). Gravitational Potential Energy. [online] Available at: http://hyperphysics.phy-astr.gsu.edu/hbase/gpot.html [Accessed 13 May. 2014].

Physicsclassroom.com, (2014). Kinetic Energy. [online] Available at: http://www.physicsclassroom.com/class/energy/Lesson-1/Kinetic-Energy [Accessed 13 May. 2014].

Falling Ball (Manuel Pascual, Javier Rojas)

FALLING BALL EXPERIMENT

Objective: To know how the distance from the floor will influence the impact exerted by the a marble into the viscous matter.

Background information: According to physics free fall consist on the one dimensional motion of an object only under the influence of gravity; earth’s 9.8m/s2 or 10m/s2 to round. We could use to measure different values during free fall with the following equations: V(velocity:m/s)= g(gravity:m/s2)*t(time:s), H(height:m)=½g*t2, and  V2=2gh.

V=gt

H=½ gt2

The forces which affect free fall (without vacuum) are: acceleration, air resistance, mass, shape, size, kinetic energy, and gravitational potential energy.

GPE=mgh

KE=½ mv2

Hypothesis: the marble will deepen the viscous matter more when the height is larger. With a low height it will deepen less. this is because the marble has more time to accelerate from a high position than from a low position, so the final velocity (when it hits the viscous matter) the ball from the high position will be bigger than the one from a low position. From a high position can store more gravitational potential energy, so when the marble hits the surface of the viscous matter the marble will possess more kinetic energy.

Materials:

-Marbles of 5 grams

-Beaker of 500ml

-Spoon

-Ruler

-Meter/Measuring tape

-Al3B5 powder

-Electronic scale

Method:

1. We have made the viscous compound, weighting 10 grams of Al3B5 powder into beaker and then mixing them with 500ml of water using the spoon.
2. Then we have took marbles of same size and weight, preparing them for their use.
3. With the help of the meter/measuring tape we have measured our first dropping distance between the ground and the dropping point,the first distance was 200 centimeters, in our experiment we will drop the marble five times in each distance into the beaker.
4. After each drop we measure its penetration into the viscous compound with the ruler, write it down in our lab book and then clean and refill the place where the marble has fallen.
5. We repeat steps 3 and 4 with other distances, with: 175 centimeters, 150 centimeters, 125 centimeters, and 100 centimeters.  
6. Wash and clean all of the used material and make a graph with your previous table of results.

Variables:

• Independent: the measurement that we will change is the initial position of the marble (from what height we let it fall. We will change this variable by measuring with a meter the height from which we will let fall the marble. Measured in cm, the throws will be from: 100cm, 125cm, 150cm, 175cm, and 200cm.
• Dependent: the depth of the penetration of the marble in the viscous matter measured in cm with a ruler.
• Controlled: The mass of the marble which remains constant at 5 grams . Because we always have used the same marble type which weights 5 grams, also we maintain cleaned the marbles. The viscosity of the matter is not change throughout the experiment, because we will have a big beaker of 500ml with the mixture to replace the viscous matter that we use in the experiment maintaining a constant viscosity.

Results:

We have stated our results on a table in order to synthesise the information easier and approach to a relevant conclusion.

Relation between the  distance of the throw and penetration of marble 

and the average energy exerted in each case

	Average Throw	1st Throw	2nd Throw	3rd Throw	4th Throw	5th Throw	Gravitational Potential Energy exerted during the fall	Kinetic Energy exerted
Throw from 100cm	3,18cm	2,8cm	2,7cm	3,2cm	3,5cm	3,7cm	0,048 Joules	48 Joules
Throw from 125cm	4,02cm	4,6cm	3,9cm	3,6cm	3,8cm	4,2cm	0,061 Joules	61 Joules
Throw from 150cm	4,24cm	4,5cm	3,7cm	3,9cm	4,3cm	4,8cm	0,074 Joules	74 Joules
Throw from 175cm	5,34cm	5,5cm	5cm	5,1cm	5,2cm	5,9cm	0,086 Joules	86 Joules
Throw from 200cm	5,94cm	5,6cm	5,4cm	5,7cm	6,6cm	6,4cm	0,098 Joules	98 Joules

Conclusion:

We have discovered how does the height affect the deepen of the marble through the viscous matter. Our hypothesis was correct and the longer the fall is, the deeper the marble goes into the viscous solution. the gravity is an acceleration number, not a velocity measurement, so the longer is the fall, more time is accelerating, and the final velocity is higher, “creating” more energy throughout the fall.

As we can see in the results, the energies all increase when the height is higher. This is because the energy is incremented by the acceleration (gravity) of the marble. The longer the fall, the more final velocity it will have, so more energy is released when during collisions with surface. We could also observe how Gravitational Potential Energy is linked to Kinetic Energy, as both have similar values in their units, so we could see how forces increment equally during the process.

Videos with a brief demonstration of parts from our experiment:

The first one show the main performance of the experiment, and the second one shows the processing of data and the measurements taken.

REFERENCES:

• Physicstutorials.org. (2014). Free fall. [online] Retrieved from: http://www.physicstutorials.org/home/mechanics/1d-kinematics/free-fall/physics-formulasfree-fall/16-free-fall [Accessed: 25 April 2014].
• Formulas.tutorvista.com. (2014). Free fall formula | formula for free fall | formulas@tutorvista.com. [online] Retrieved from: http://formulas.tutorvista.com/physics/free-fall-formula.html [Accessed: 28 April 2014].

DONE BY: MANUEL PASCUAL FERNÁNDEZ & JAVIER ROJAS CARRILLO FROM 10C