Rubber Band Lab

Big Questions:

"How can we store energy to do work for us later?"

“How does the force it takes to stretch a rubber band depend on the 

AMOUNT by which you stretch it?” 

Purpose: The purpose of this lab was to find the relationship between distance and force by stretching a rubber band. We also learned about spring(elastic) and potential energy, represented as Us. 

Lab: In the first round of this lab we only looped the rubber band around once and measured the amount of force exerted for every centimeter we pulled the band. Then in round two we double looped the rubber band and recorded our findings in a table and chart. In each round we pulled the band from 1 cm all the way to 5 cm. We found that the relationship between force and distance in this lab is directly proportional. 

K Value/ Spring Constant: For this lab the slope of x(stretch distance) vs Fs( force in spring) is the spring force. Next we tried to figure out the potential energy of our rubber band. Our graph was in the shape of a triangle so the formula for the area of a triangle to convert it into Us= (1/2)kv. 

Real life Connection:

 A sling shot. The farther you pull back a sling shot the farther the object will go. If you don't pull hard enough, the sling shot won't produce enough energy and the object won't go far. Here is a link on the science behind slingshots-http://www.sciencebuddies.org/blog/2011/08/slingshot-science-the-physics-in-angry-birds.php 

Pyramid Lab

Purpose: The purpose of this lab was to discover if the product of force and distance is universally conserved by using a simple machine.

Lab: In this lab we pulled a car up a ramp at a steady pace and had the electronic device record the mean of the force. Each trial we shortened the distance on the ramp that the car traveled to see if it had an effect on the force. Once all the data was collected we put together our findings using a bar graph.























Key Ideas: We learned that the relationship between force and distance is inversely proportional. This means that if the force goes up, then the distance goes down and if the force decreases, then the distance increases. The area is force times distance equals work (Fd=W). Work is a form of energy measured by joules and a  joule is a newton times a meter (Nm). The answer to the big question "is work conserved?"is yes because it always stays the same.

Real world connection: Running. In cross country it is usually harder to run up the shorter but really steep hill than it is to run a longer hill with less of an incline.This is because there is less force going against you on the longer hill than there is on the steep one. Both hills take the same amount of force, because work is universally conserved.

Simple Machines: Pulleys

Big Question:

"How can force be manipulated using a simple machine?" 

"What pattern do you observe regarding the relationship between force and distance 

in a simple machine? "


Purpose: To find the relationship between force and distance

Lab: In class we built two pulleys. There was one with just one wheel but the other had two. We attached weights to the pulleys to see how the force could be manipulated. The two wheeled pulley contraption could lift a weight with another one of half its mass. We learned that this could occur if there was less force and more distance. The relationship between force and distance is that F and d are inversely proportional. A greater applied force requires less distance while a lower applied force requires more distance.

(Standard 3.5) We built a simple machine and performed a quantitative analysis of its performance based in the notions of work and energy conservation by filling in a data table with our findings.

Real World: In real life we use pulleys in our everyday lives. One example is in gyms many people use pulley devices to get in shape. Heres a video of a pulley in action:
http://www.youtube.com/watch?v=e-mUiyCpQng

Mass vs. Force Lab

Purpose: 
The main purpose of this lab was to learn about the relationship between mass(kg) and force(N). We discovered how to measure force in a reliable and repeatable way by finding the formula for gravity. We also had the chance to practice making tables and graphs with the data we collected. Finally, we learned how to read the graph and tell what a best fit line looks like. 

Materials:

                                                                                                

• Brass weights ranging from 20kg-1000kg(masses)
• Spring gauge(to calculate force)

During the lab: While measuring the different weights, we realized that the force was directly proportional to mass. 1kg is 10N, .5kg is 5N, .2kg is 2N, and ect. 

Key Ideas:

• 10N of force are needed to support 1kg of mass
• F=gm
• F stands for force of gravity
• g stands for earths gravitation constant(10N/kg)
• m is the independent variable
• g is the slope
• the best fit line is the pattern or theory
• weight is different than mass

Real World Connection:
Roller-Coasters!
The law of gravity is:what goes up must come down.The mass of the roller-coaster itself directly effects the force and as it gains height because the higher it goes up, the faster it will come down. 

Here is a link to a video on the science behind a roller-coaster:

http://dsc.discovery.com/tv-shows/other-shows/videos/time-warp-roller-coaster-science.htm