HS Physics SMILE Notes

28 October 1997

Prepared by Alex.Junievicz

Roberta Williams [IIT Physics Graduate Student]

--Power of a Grape-- apparatus- Fruit Powered Clock

Zany Brainy \$13

Cut grape in half, constructing 2 cells

Cu (+) and Zn electrodes

Grape .92 V and 0.058 mA when shorted [internal resistance thus 16000 Ohm]

Lifetime of grape as battery to drive LCD clock = 4 days [the grape is pretty well dried up at the end.]

(caution one must use a Voltmeter with very high internal resistance!)

Karlene Joseph [Lane Tech]

-apparatus Push and Go Toy [Dinosaur Cars; etc]

car found in Toddler

It is hard to find cars that work and don't disappear or break into sections (TOMY ) Toys R Us \$5.00

Causes of errors by students 1. Bad data

2. Misconceptions

When students work in lab groups here in (4). There must be something to unite the experience

of the group, and it is the Lab summary.

-A way of using ticker tape - the push car --review-

She used the 60 cycle sparker, carbon paper, and a strip of tape. The tape can provide more feeling and information to the student than a graphing calculator and a sonar sensor. The student lets the car make a pass and has a tape with 6 dots per .1 sec. He then labels the tape and cuts it into 6 dot sections (1/10 sec) and then attaches the paper strips to form a chart showing the distances traveled in each .1 sec. At the start the lengths are ascending and then level, and afterwards fall back to 0. Using the tape to make the graph, one may then determine the slopes and calculate the acceleration and thus the forces.. [ Mass of Car .264 Kg] Also, the area under the curve gives the corresponding change in displacement.

Porter commented that the friction is always present. If on frictionless ice the cart will never accelerate. Friction is always present and is the "cause" of acceleration.

Bill Shanks [Joliet Central HS, retired]

Bill brought in a True Value flashlight that was said to be designed by Physics people. The flashlight is square and is said to have no reflectors. A the front surface looks like a type of Fresnel lens, but actually is not that at all. He suspects t hat total internal reflection from prism surfaces is used to bend the light. The flashlight projects an beam for at least 1/8 mile [250 m]

Small (4 AA cells) \$13 Large (4 D cells) \$20

Porter Johnson

Argonne Information Center [at main entrance just West of Cass Avenue and South of the Stevenson Expressway] is now open with science exhibits.

Ann Brandon [Joliet West HS]

AAPT Nov 8 8am - 1 pm at IIT in Siegel Hall [with afternoon workshops]

(Uniformly accelerated motion)

vf = v0 + a t

d = ˝ a t2 + v0 t

v = [vf + v0]/2 = d/t

vf2 = v02 + 2 a d

there are 4 formulas because there are 5 variables [ vf, v0, d, a, t] and each has one variable missing

Carol Zimmerman [Lane Tech HS]

An alternative to the Great America Trip for those who cannot afford the time, or money. The Museum of Science and Industry can be a good field trip. To facilitate that she has prepared a survey of things to find and visit. She passed out several co pies of the survey and the teacher’s key, and she also had copies of the survey on 3.5" disks in the W95 word format. She also requires a signed receipt indicating admission (by someone working is Museum of Science and Industry).Things have to be f lexible because of the potential for changes at the MSI.

Sandra Broomes [Sherman Elementary School]

She went to a seminar on Hallowe’en Treats ["boo fest"] at Museum of Science and Industry.

She shared a "floating GHOST" with us and a "Balancing GHOST." A thick paper was cut out like a ghost with tails protruding laterally and paper clips were put as low as possible to the center of gravity and as far laterally so that it would balance on a finger.

Jamie Chichester [Lincoln Way HS]

He showed the Bandit A cross-bow device

Try Mayers -- Sportmart \$20.00

6pk of darts approx \$6-9

Put face on board with a apple on it. Then he used a laser pointer to show where it was aimed and then shot a dart, of course it landed below the apple, and then moved back with a lower position, and further

back what would happen ("Ask your neighbor") and of course it struck lower. (another version of the "dartmong dart" gun, but with seemingly better sticking darts, and laying a laser pointer in the trough gave a way of aiming the system.)