For our experiment we chose to look at the physics of slinkys in a fun and interesting examples. For materials we used 6 text books, a stopwatch, a weight scale, ruler, 2 different slinkys of different size and mass.
Physics Lab: Slinky Physics and Motion (Handout)
Purpose: To look at the correlation between how the size and weight of an object affect its speed.
Background: Translational momentum is the product of the mass and velocity of an object where (p=mv). Similar to velocity, linear momentum is a vector quantity where the magnitude of the vector is the distance between the two points and includes the direction of displacement from point A to B which will be showcased in the below experiment. According to Newton’s 2nd Law, the rate of change of the momentum of a particle is relative to the resultant force acting on the particle and is in the direction of that force. In this case the direction will be a gravitational pull at a falling 90 degree angle. Mass is the dependent variable in the experiment where the heavier the mass, the faster it will travel when the same momentum is given. Heights from which the object falls will also be altered to see if the correlation between the size and mass of the object is changed as heights increase or decrease as well. From a sustainability standpoint, the correlation between size and mass and its speed is applicable to many energy concepts like the size and mass of a car model altered to improve its optimal speed and fuel efficiency.
Procedure:
- Stack six books like stairs
- Measure the height of the books and the height of the incline
- Determine the mass of each slinky
- Put the slinkys one end at the top of the stack and the other end on the next step
- Push the slinky with the same momentum force each trial and track the speed of how long it takes to “walk” down the books
- Release the slinkys over the “steps” when it is at the 90 degree angle and the gravitational pull of momentum is pulling the slinky down the steps
- Do this 3-5 trials
- Vary the height of the book steps by taking away one or two books and do 3 trials at these heights
- Calculate velocity: d/t
- Using equation P=MV where P is momentum (mass and motion), M is the mass and V is the velocity, the equation shows that momentum is directly proportional to an objects mass and directly proportional to an objects velocity.
- Record trials in data formatting on the lab handout
Data:
Smaller slinky:
Mass (g) 207
| Distance(Trial 1): .23m | Distance (Trial 2) .23m | Distance (Trial 3) .23m |
| Time in seconds: 1.1 | Time in seconds: 1.1 | Time in Seconds: 1.1 |
Larger slinky:
Mass (g) 124.5
| Distance(Trial 1): .23m | Distance (Trial 2) .23m | Distance (Trial 3) .23m |
| Time in seconds: 1.8 | Time in seconds: 1.7 | Time in Seconds: 1.8 |
Velocity: 0.23 m/1.1 seconds = 0.21 m/s ( smaller slinky, mass: 207 grams)
Velocity: 0.23 m/ 1.77 seconds = 0.13 m/s (larger slinky, mass: 124.5 grams)
*Put into excel for graphical representation
Analysis:
Do the different masses of the slinkys change the velocity?
Yes
a) If so why do you think this is true?
The slinky with the greater mass of 207 grams traveled faster at 0.21 m/s. The heavier the mass, the faster the slinky traveled down the “steps” With the compression and longitudinal waves that the slinky has in movement, the heavier mass gets pull down at a higher speed because of the natural momentum of gravitational pull that pulls the heavier mass down the “steps” at a faster rate.
Below is a graphical representation of the velocity and mass
*Factors contributing to slinky movements: Longtiudinal waves, compression, mass and the momentum of gravitational pull*
Doing this experiment with students from the other class was a great learning experiment. They all participated willingly and ended up getting the same results we got and understanding why our hypothesis was correct. Learning from their experiments as well was a perfect way to integrate everything we have learned over the semester and really tied everything together. We got to cover so many variables in sustainability from simple laws of physics , to photovalactic cells, and greenhouse effects.