Group+3

Becky Logan Brandon
 * Exploring Friction **

Together with your group, come up with a name for your group in the spirit of our physics unit!
 * Our Group Name: the Elite Electrons**


 * Work through this lab as a group. Try to encourage everyone to be involved, have a voice, and use their skills!**

What is the definition of friction? The force that resists motion between two touching surfaces. Define these two types of friction: Static Friction – is generally greater than kinetic friction and must overcome before an object can set in motion

Sliding Friction – the friction between two bodies that are in sliding contact (also kinetic friction)

Use the blocks, masses, and spring scale to make observations on the amount of force needed to get a mass moving and the amount of force needed to keep the mass moving. Write down your observations.
 * Observations:**
 * Block is 120 grams when hanging from the pole
 * Block is 20 grams when dragged across table
 * 120 grams when held from a finger

Spring scales measure force. Weight is the force on an object due to gravity but a spring scale can also measure the force needed to pull an object. If the spring scale reads 100 g it means that the force is about 1 N. If the spring scale reads 200 g it means that the force is about 2 N.
 * About the spring scale –**

A triple beam balance measures mass in grams. Since w=mg where w is weight in N, m is mass in kg, and g is 9.8 (acceleration due to gravity) then we can convert the mass on our balance to weight using the formula below. Weight (N) = Mass (kg) X 9.8 or Weight (N) = Mass (g) X 0.0098
 * About the triple beam balance –**

1. Experiment by pulling the block with the hook using the spring scale. Lay the block down on the table so that the largest surface is in contact with the table. Try applying such a small force that the block doesn’t move. What did the scale read when the block just begins to move? __g =__ N //This number represents the force of static friction between the block and the table.// //Block with hook= 117.7 grams x 0.0098= 1.15346// //When slightly dragged= .2 grams x 0.0098= 0.00196// //Block 2= 107.1 grams x 0.0098= 1.04958// //Block 1&2 dragged= .4 grams x 0.0098= 0.0392// //Block 3= 117.9 grams x 0.0098= 1.15542// //Block 1,2&3=// //Block 4= 95.3 grams x 0.0098= 0.93394// //Block 5= 151.7 grams x 0.0098= 1.4866//
 * Conduct an Experiment**

2. Continue pulling the block across the table at a steady speed. What did the scale read as you pulled the block at a steady speed? __g =__ N //This number represents the force of sliding friction between the block and the table.//

3. Create a data table to record the forces of static and sliding friction as you increase the mass of the blocks/objects you pull across the table. Be sure to convert the mass to weight using the formula above. Create another row for each set of blocks you pull.
 * Objects || Mass (g) || Weight (N) || Static Friction (N) || Sliding Friction (N) ||
 * Bock 1 || 117.7 || 1.153 || 0.4 || 0.2 ||
 * Block 1+2 || 118.8 || 1.164 || 0.6 || 0.4 ||
 * Block 1+2+3 || 354.4 || 3.473 || 0.8 || 0.6 ||
 * Block 1+2+3+4 || 449.7 || 4.407 || 1.1 || 0.8 ||
 * Block 1+2+3+4+5 || 601.4 || 5.893 || 2 || 1.1 ||

4. Stop and analyze the data in your table. Describe the relationship between the weight of the objects you pulled and each type of friction. What is the pattern seen in the table? The static friction takes more force than the sliding friction. The static friction increased pretty steadily but at the end started going higher. The sliding friction went up steady until the last one. It went up by 2 every one. Static friction is greater than sliding.





5. Create a graph to show the relationship.
 * Identify the independent variable for the x- axis: Weight
 * Identify the dependent variable for the y-axis: Force of Friction
 * What type of graph is appropriate for this set of data? Scatter Plot
 * What can be done to distinguish the static friction data set from the sliding friction data set? Different color
 * Create the graph using “Create a Graph” or paper and pencil.

6. Stop and analyze the graph of your data. Describe the correlation between the weight of the objects you pulled and each type of friction. How is the correlation shown in the graph? The static friction takes more force than sliding friction. When there is more weight then the friction is greater.

Choose a question from below or develop your own unique question with your lab group. Design and conduct an experiment to help find the answer to the question. Complete an experimental design diagram and have it approved before beginning. If the surface is smoother then there will be less friction. For example if we did it on an ice block then it will go much easier but if it was on something rough or catchy like a carpet then there will be more friction. __Experimental Design Diagram__ __Question:__ Will the force of friction be greater if the surface is rougher? __Hypothesis:__ I think the force of friction will be greater when the surface is rougher. __Independent Variable: T__he weight of the blocks
 * Your Turn**
 * 1) How would the amount of static and sliding friction change if the bottom block was placed so the smaller surface was in contact with the table?
 * 2) How would the amount of static and sliding friction change if the blocks were placed on a different surface?


 * Levels of the IV: || (Control)  ||   ||   ||   ||   ||
 * Repeated Trials: || 1 || 1 and 2 ||  ||   ||   ||

__Dependent Variable:__ Force of friction __Constants:__ The surface type,spring scale __Procedure:__ We will take all the blocks to the carpet in the school office where we will test the blocks on the rough surface and measure the force of friction __Data Table:__ __Graph:__
 * Objects || Mass (g) || Weight (N) || Static Friction (N) || Sliding Friction (N) ||
 * Bock 1 || 117.7 || 1.153 || 0.7 || 0.4 ||
 * Block 1+2 || 118.8 || 1.164 || 1.0 || 1.0 ||
 * Block 1+2+3 || 354.4 || 3.473 || 1.3 || 1.2 ||
 * Block 1+2+3+4 || 449.7 || 4.407 || 1.8 || 1.7 ||
 * Block 1+2+3+4+5 || 601.4 || 5.893 || 2.6 || 2.2 ||