Third Laboratory Experiments
Name:_____________________________________________________________
I. Human Reaction
Time Measurements:
In this experiment you will measure the reaction time of your laboratory partner. You will do this by dropping a ruler between your lab partner’s fingers and measuring how far it falls before he/she can grab it.
____________, ____________, ______________, ____________, ___________
What is the average distance that the ruler fell? _____________________
Using the equation d = (g/2) t2, where g = 980 cm/s2, determine the reaction time of your lab partner. Show your work below:
Reaction time = ________________________
Write your answer on the board in front of the class for comparison with the other students.
In this experiment you will measure the pressure on the ground due to your feet while standing.
Area = ______________________ Pressure = _______________________
In this experiment you will determine an estimate of your aerobic power and maximum power while going up stairs.
Height of stairs = ________________________________
Time for aerobic walk = _______________________________
Time for run = ______________________________________
Using power = work/time, and that work = force x distance (i.e. weight x height), determine your power output for both aerobic walking and running. Show your work here:
Total work = ___________________________________________________
Aerobic Power = ___________________________________________
Maximum Power = __________________________________________
If you were to walk up stairs for 30 minutes, how many food calories would you burn? Assume that the body is 15% efficient.
In this exercise you will experiment with lenses by producing different sized images. The light bench at your table will able to hold a lens and a glass plate on which an image will be formed. You will be given two lenses, one will be thicker in the middle than the other.
a) Finding the focal length of the thicker lens: Parallel light hitting the lens will focus at a point on the other side of the lens. Place the lens in the holder, and the holder as far away as possible from the light source. Focus the image on the screen. Measure the distance from the lens to the image. This distance is (approximately) the focal length of the lens.
Focal Length of thick lens: _____________________________________________
b) Move the lens and screen to form an image that is smaller than the object.
Distance of object to lens: ___________________________________
Distance of image to lens: ___________________________________
c) Move the lens and screen to form an image that is larger than the object
Distance of object to lens:____________________________________
Distance of image to lens: ____________________________________
d) Finding the focal length of the thinner lens: Repeat part a) for the thin lens.
Focal Length of thick lens: _____________________________________________
b) Move the lens and screen to form an image that is smaller than the object.
Distance of object to lens: ___________________________________
Distance of image to lens: ___________________________________
c) Move the lens and screen to form an image that is larger than the object
Distance of object to lens:____________________________________
Distance of image to lens: ____________________________________
1. Use the diffraction grating and examine the light emitted by the tungsten filament (incandescent light source) and one of the atomic sources (florescent light source). What is the main difference in the color spectra given off by these two types of sources? Comment:
Source 1 =
Source 2 =
Source 3 =
In this experiment, you will use Doug Johnson’s motor. Each lab desk will be given a motor base with battery. You will make the motor armature, and see how fast it can spin.
3. Test out your armature to see how fast it spins. Keep experimenting until your armature spins as fast as it can.
What happens to the direction of rotation of the armature if you turn the magnet around?
What happens to the direction of rotation of the armature if you turn the battery around?