Group+4

Together with your group, come up with a name for your group in the spirit of our physics unit! 0 gravity
 * Exploring Friction **
 * Our Group Name:**


 * 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 resistance that one surface or object encounters when moving over a surface. The force that resists motion between two touching surfaces Define these two types of friction: Static Friction – Friction between two or more solid objects that are not moving relative to each other

Sliding Friction –a force of resisting the relative motion of a solid surface

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. The more blocks we add on the more friction against the table Block 1-136.8 block 2-132.2 block 3-150.6 block 4-163.6 block 5-106.9
 * Observations:**

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.//
 * 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) ||
 * block 1 || 136.8 || 1.3 || .4 || .2 ||
 * block 1&2 || 269 || 2.6 || .8 || .4 ||
 * block 1&2&3 || 419.6 || 4.0 || 1.2 || .6 ||
 * block 1&2&3&4 || 583.2 || 5.7 || 2 || .8 ||
 * block 1,2,3,4,5 || 690.1 || 6.8 || 2.2 || 1.2 ||

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 weight of the objects pulled goes up at a constant rate on both the static and sliding friction.

5. Create a graph to show the relationship.
 * Identify the independent variable for the x- axis: Weight (N)
 * Identify the dependent variable for the y-axis: sliding friction (N)
 * 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?
 * 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?

There is positive correlation between the two types of friction (Sliding and Static).

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. __Experimental Design Diagram__ __Question:__ How would the amount of static and sliding friction change if the blocks were placed on a different surface? __Hypothesis:__ The amount of static and sliding friction would increase if placed on a rougher surface. __Independent Variable:__ Surface
 * 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)  || Colored table tops || Floor || Construction paper ||   ||
 * Repeated Trials: ||  || 1 || 1 || 1 ||   ||

__Dependent Variable:__ Static and Sliding friction __Constants:__ Mass of 4 blocks __Procedure: weight-__ 4.9 newtons __Data Table:__ Colored Table top- static- 2 sliding .12 Floor- static- 2 sliding- .12 Carpet- static-1.2 sliding-1.6 Construction paper- 2.2 sliding- 1.2

__Graph:__