WEDNESDAY, JAN. 7 TH p. 124, 125

WEDNESDAY, JAN. 7 TH 124 1/7/15 Wed. L.T.: I can write a hypothesis and a procedure to a lab designed to analyze where a marble’s forces will be balanced or unbalanced as it travels across the room. DO NOW: Describe when a moving object’s forces are balanced and also when they’re unbalanced. Give an example of each. ……………………………. Reflection: Did you fully participate in the lab practice? Did you complete your hypothesis and procedure? Explain what we are trying to find out through this lab. 125 Title: Rolling Along Lab Q: When and why will the steel marble’s forces be balanced or unbalanced as it rolls across the room? Hypothesis: (words or diagram with labels) Procedure: (variables, #ed, logical steps) ………………….. Data Table: (time permitting)

 Yesterday’s Responses:  Overwhelming 1 st place :  1. Quintin: “No, if something in motion, forces are unbalanced.”  ………………………………………………………………..  Very distant 2 nd and 3 rd places:  2. Frank: “I thought that if an object’s speeding up or slowing down, that it’s because an unbalanced force was acting on it.”  3. Quintin: “He should be slowing down because of friction.”

 Informally go through the lab together…  I need:  8 timers  8 calculators  8 checkers (no supplies, just good eyes)  Supplies are up front or you can use phones!  …………………………  Everyone needs to be organized and on the same page for this to work! Listen and watch for instruction…  We will practice this a few times for everyone to understand how we set up and how we gather data. Gather materials and make 4 teams with 2 of each job! (6 people total) If we don’t have enough people, make sure you have at least 1 of each job (3 people total).

HYPOTHESIS A B C D E Describe whether forces will be balanced or unbalanced on the marble at these intervals and why: A-B B-C C-D D-E 0.62 m

PROCEDURE  What are our variables? Do we even have all 3 variables in this lab?  ………..  Logical, numbered, detailed steps:  - How do we set up this lab? (A diagram might be useful…)  - What do we do to collect data?  - What are some details we should be mindful of?

 Procedure:  Section 1 - Variables  CV:  RV:  ………………………….  Section 2 – Set Up  Make a diagram of set up with labels:  ………………………….  Section 3 – How to Collect Data  Write numbered, logical, detailed steps of how to collect data. Also add anything we should pay extra attention to:  1.  2.  3

 CV: the set distances between A-B, B-C, etc. need to be consistent between trials, slope of angle, type of ball, surface type, how ball is released  RV: time (seconds ball takes to travel intervals) so we can calculate avg. speed

SECTION 3 – HOW TO COLLECT DATA  1. Organize people timing each section to start their time when the ball rolls into their zone and when it rolls out of their zone.  2. Release marble at top of ramp at point A. Times in A-B zone starts timer. When marble reaches point B, A-B timers stop time.  3. As the marble travels down length of track, timers will start and stop their timers at designated points.  4. If there are multiple timers, report time to calculator who will average times and report to Ms. Kim (class data table).  5. Repeat steps 1-4 for a total of 3 trials.  6. Average times. Then use average time to calculate average speed of marble for each section.

DATA TABLE DistancesTrial 1Trial 2Trial 3Avg. TimeAvg. Speed A-B B-C C-D D-E