High School Physics SMILE

24 March 1998

Notes taken by Alex Junievicz

Global Warming

Major countries contributing to global warming due to industrial activity:

United States France Japan

Major sources of air pollution

Acid Rain

CO₂

Methane: CH₄

She showed that an accumulation of small items eventually does produce a large effect. She had each student put a bag over someone's hands eventually allowed their hands to show an increase in temperature. (24 plastic bags)

He gave an update on his ocular problems, emphasizing the "physics" in his treatments.

He commented on the use of a storage oscilloscope and a pulse to determine the geometry of the parts of the eye, and thus what focal length lens would be needed. The procedure uses a single pulse in the seen on the "MegaHertz oscilloscope trigger", which was reflected in the eye at the interface between the salt water and silicone oil [used in the process of replacing the natural fluids in the eye], and also at the back. The velocity of sound in salt water is about 998 m/sec; in silicone oil about 700 m/sec.

From the floor there was a comment that B ultrasound also measured the intensity and the distance of the reflection.

She showed the Bernoulli effect by taking a hair dryer and placing a balloon (later with more success a ping-pong ball) that the ball was lifted in the stream of air.

Her source was "Science in the Bible":

But those who hope in the Lord

will renew their strength.

They will soar on wings like eagles;

they will run and not grow weary,

they will walk and not be faint. -Isaiah 40:31

He showed a way of measuring mass using nickels.

Mass of one Nickel = 5 grams [very nearly]

By balancing a 1/2 meter stick on the center of mass (should be 1/2 the length) and putting nickels on one side, and the object on the other we can determine the mass of the object, and moving the nickel toward the balance point we can determine part of the 5grams to get an accurate measure.

She noted that the back of the hand possesses less "rubbing friction" than the palms. If you rub the back of your hands there is less friction and less warming.

She showed the waves on a slinky and the reflection by putting cups on the table and then producing a wave noting the excitation distance that was swing was much less than that of the wave in the spring.

She also showed a slinky held up at one end and dropped. She noted that the top would fall to the level of the bottom before the slinky would fall. She commented that the spring stretched out would pull up the bottom even though the bottom was pulled by gravity. The net result was that the bottom was stationary until there was no spring pulling up.