Subject: Science

Unit: Forces and motion

Section: Forces and friction

Assignment title:  Friction lab: impact of surface and mass [can work with a partner]

Points:  30

Prerequisite:  Friction interactive

Performance target:  show, using drawings, presentations, or physical motion, and explain, written or verbally,  the difference types of forces which can act upon an object

Tools : access to internet for research, print out of this document, spring scale, cart, 1 kg object [2], various surface types [desk top, cardboard, material or carpet, sand/sandpaper, other of choice], masking tape, white ramps, writing utensil

Directions:

1. Complete the opening questions, using internet and the linked Google presentation [link in doc and on website]
2. Complete the exploration, graph, analysis, and conclusion. [15-25 point bonus if convert this ‘report’ into a digital format]

Evidence & expectations to be met:

• Lab actions  [3 points/item= 12]

• responsible behavior and use of time
• conservation of resources
• cleaned up or stowed equipment properly upon completion of work time
• worked independently, utilized available resources to complete activity and find answers

• Document  [3/item= 18]

• completeness with legible writing and followed ELA conventions
• Graph accurately represents the data, has all required components, used a straight edge, created with precision
• Analysis of results connects directly to observations
• Analysis states specific data to support answers
• Conclusion summary is in a separate doc, written in paragraph form and addresses all points
• Conclusion summary references specific data to support claims and uses physics terminology in responses

Worksheet

Background notes:

1. Newton’s second law states: _________________________________________________________________________
2. So what does this actually mean? Explain the law in your own words.

3. Friction is a force that works in the _________________________________direction of the motion of an object.
4. In order to change the motion, v_ _ _ _ _ _ _y, and a _ _e _ _ _ _ t_ _ _  of an object you have to apply enough _______________ to overcome the force of the f _ _ _ _ _ _ _ between the object and whatever it is resting on.
5. Force is measured in units called: ___________________. The abbreviation of this unit is _______.
6. One newton is the amount of force required to __________________ an object that is one ______ in mass at a rate of  one _________/______________.
7. In your own words provide an example of what a newton is:

Use the Google Presentation to assist with the following questions

A ____________ scale is a measurement tool used to measure the amount of ____________ acting upon an object.

On the back of this page:

Create a labeled diagram AND list the steps to use a spring scale:

Exploration:

Materials: spring scale, cart, two 1 kg objects, white ramps, surface materials to test [see data table] set up to = 1 meter in length

Procedure:

1. Connect two white ramps together using masking tape; position to form a banked track
2. Using a WASHABLE marker or pencil mark off ONE meter in length
3. Line the ‘track’ with surface material to be tested
4. Make qualitative observations about each surface area by writing a three-six adjective description.
5. Make some predictions about what you think will happen

1. Which surface will require more force to overcome inertia and friction? _______________________  WHY? _________________________________________________________________________
2. Which cart will require less force to overcome inertia and force?  ___________________________ WHY? _________________________________________________________________________

6. Use the spring scale and a steady pulling motion to force the cart across the surface ...three times [try and maintain your pull speed = to 1 meter/second each time]

1. empty cart
2. cart with 1 kg mass added
3. cart with 2 kg mass added

7. Record the total N and increments [ example 1.4N] on data table
8. Repeat process for each surface
9. Create a triple bar graph comparing the amount of force needed to pull the cart [empty, 1 kg, 2kg]  across the different surface areas
10. Complete the analysis and conclusion questions

Observation/data table

Calculate the change in force for each surface/cart mass [example table top:  N of 2kg cart - N of empty = amount of change]

Tabletop:

Cloth:

Sand/sandpaper:

rolling surface:

Explorer’s choice:

Graphic picture of your data...Triple bar graph [What is this? Review Interactive -Interpreting graphs in Science skills: Understanding data]

Analysis:

1. Describe the graph’s overall shape *Huh? Review: Science skills: understanding data introduction to histograms. 
2. Based on the graphs shape what information stands out?
3. Are there any outliers? *Huh? Review: Science skills: understanding data: introduction to stemplots
4. The surface requiring the most force, regardless of the carts mass, to overcome inertia and friction is:
5. The surface requiring the least force, regardless of the carts mass, to overcome inertia and friction is:
6. What does the graph show you about the relationship between surface type, mass, and force [be specific]

ON A SEPARATE SHEET OR DOC COMPOSE YOUR CONCLUSION

Conclusions composed into paragraph form and addressing the following:

• Using your data to support your claims explain the impact of surface type on force required to move an object.
• Using your data to support your claims explain the impact of an objects mass and the force required to move an object.
• Using what you have observed explain the impact, on the movement of trucks based on the surface type and mass.  

• Two semi-trucks, one with an empty trailer and the other carrying a full load:

• Coming to a stop on an icy road
• In motion transitioning from a highway to a gravel road [rolling surface]