Date: _______________________
Name: _____________________________________
Partner’s Name: _____________________________________
Physics
Lab: Toy Poppers
Mr. Alaimo
(Based on a lab from Arbor Scientific Inc.)
Objectives:
1.
2.
Apparatus:
The student will be able to verify the law of conservation of energy for a popper.
The student will be able to experimentally determine the kinetic, gravitational potential energy, and
elastic potential energy for a toy popper.
Popper toy, meter stick, electronic balance.
Background Information:
The conservation of energy presents a unifying concept in physics. If a system does not interact with its environment in any way,
then certain mechanical properties of the system cannot change. They are sometimes called “constants of motion”. These quantities are said
to be “conserved” and the conservation laws which result can be considered to be the most fundamental principles of mechanics. In
mechanics, examples of conserved quantities are mass, energy, momentum, angular momentum, and electric charge.
(The above passage is excerpted from the HyperPhysics web site @ http://hyperphysics.phy-astr.gsu.edu/hbase/conser.html.)
Procedure:
1. Obtain a popper from Alaimo & measure its mass using the
digital balance.
Mass of popper (in kg): ____________________
2.
Invert the popper and record the exact distance you
compressed the popper to invert it. Measure this carefully
with a ruler.
h
popper
Compression Distance (x) of popper (in m): ___________
3.
Using the set-up above, compress the popper and set it on the floor. When the popper pops, your lab partner must
attempt to measure the maximum height the popper reaches. Repeat this for 10 trials.
4.
Complete the Data Table:
Data Table 1: Popper Height Data.
n
1
2
3
4
5
6
7
8
9
10
Maximum Height h
of popped popper
from floor to top
(m)
Average Height of
popper
(m)
5.
Using the equation, Epg = mgh, determine the Gravitational Potential Energy for the popper. Show your calculation at
the bottom of the page.
Epg of Popper = _____________________ (record your answer to 6 decimal places!)
6.
Next, using ONLY this motion formula, vf2 = vi2 + 2ax, determine the final velocity of the popper just before it hits
the ground. Show your calculation at the bottom of the page. (HINT: Ask yourself, what is the popper’s initial
velocity at max height?)
vf of Popper = _____________________ (record your answer to only 4 decimal places!)
7.
Using ONLY your answer for the velocity of the popper from question #7 and the equation EK = ½ mv2, find the
Kinetic Energy of the popper just before it hits the ground. Show your calculation at the bottom of the page.
EK of Popper = _____________________ (record your answer to 6 decimal places!)
8.
Compare the Potential Energy to the Kinetic Energy for the popper.
Epg of Popper = ________________
9.
EK of Popper = ________________
Was Energy conserved in this case? __________________
10. If the kinetic energy and the potential energy are not conserved, give some reasons why this might not be the case.
_________________________________________________________________________________________
_________________________________________________________________________________________
11. Using the equation for the Elastic Potential Energy of a spring, EPE = ½ kx2, determine the Spring Constant for
YOUR Popper. Show your calculation at the bottom of the page.
k for YOUR Popper = ________________
12. Find 2 other lab group answers for k and draw a conclusion about height h and k.
_________________________________________________________________________________________
_________________________________________________________________________________________
13. What 2 ways could the toy manufacturer engineer a popper to make it go higher?
_________________________________________________________________________________________
_________________________________________________________________________________________
14. What force did you apply in compressing the popper? Show your calculation below. (HINT: According to Hooke’s
Law, F = kx.)