Things to think about on PI-2

Horizontal projectiles using marblesSample Procedures included

Things to think about

• This is a horizontal projectile lab. Does your set up allow the marble to roll off the table or counter?• You are allowed a 10% variance in velocity from your median

average velocity. Can your data collection procedure allow for that range?• Are your procedures specific enough to allow repeatability

by another group without them having to ask you for instructions?

Sample procedures – Experimental Set-up1. Roll a paper into a tube with a 1 inch diameter. Tape the tube and

crease 1 end into a “v”.2. Place 2 tables together so that a groove is formed at the joint

between the 2 tables. 3. Place one book at one end of the table. Place the round end of the

tube 15 cm from the end of the book. Place the “v” end of the tube on the groove between tables so that the tube forms a covered ramp.

4. Place the two photogates 50 cm apart along the groove.5. Make sure that the marble will fall off the table after passing through

the photogates.

Sample Procedures – Data collection – calibrating the independent variable6. Open SPARKvue. Scroll down the menu until you find photogate timing. Click

on photogate timing.7. On the next screen choose velocity between gates. (This will insure that it

measures the speed as it passes through the 50 cm space.)8. Place the marble at the top of the tube. Press “play” on the SPARKvue screen.

Count down 3…2…1 and release the marble.9. Record the velocity data.10. Check to make sure your data is within the 10% allowable variance.11. Repeat 4 times.

Sample procedures – Collecting the distance data1. Measure the height of the lab table and record it in your data.2. Place a meter stick at the base of the table.3. Roll the marble through the photogates and let the marble fall to

the ground. Use the meter stick to measure the distance the marble fell from the table. Record the speed from the photogate set-up.

4. Repeat 3 times.