Saturday, April 17, 2010

Temperature Interactive


After visiting http://funphysics.jpl.nasa.gov/adventures/temperature-game.html, I knew a lot more about temperature than before. Did you know that….

Boiling Point = 212ºF
Death Valley = 134ºF
Human Body = 98.6ºF
Room Temperature = 68ºF
Freezing = 32ºF
Mars = -81ºF
Antarctica = -128ºF
Saturn = -229ºF
Space = -454.54ºF
SuperFluid Helium = -455.76ºF

Heat plays a major role in atomic or molecular motion, Molecules move rapidly in a gas or liquid when it’s hot and slower if it’s cool. Moreover, atoms vibrate when for a solid. Lastly, there are three different units of temperature
-Celsius
-Fahrenheit
-Kelvin

Convection Popcorn Lab

Have you ever wondered why popcorn pops? Magically, people put these small, brown kernels into the microwave for a few minutes, and the result is a delicious, white, fluffy snack! How did this happen? I was thinking this exact thought I made popcorn in science class. Here's how it happened... There was a small droplet of water in each kernel (specifically the endosperm) which expands and converts into water vapor when heated. This puts pressure on the endosperm which eventually enhance in size and fills with air. Because of the building pressure, the kernel’s pericarp pops, and the kernel flips inside out. Thus, the white starch known as popcorn is now visible. Here are some interesting facts you should know in order for a popcorn kernel to pop.
1.) There must be 13-14% of water in the kernel.
2.) The kernel's pericarp must be strong enough to endure the pressure until it is the "right time" to pop.
3.) The kernel will not explode if it has a damaged (cracked) pericarp, thus causing the moisture to escape.
4.) Temperature must exceed 300 degrees F Picture and information from

http://www.tellmewhyfacts.com/2006/11/why-does-popcorn-pop.html

The Greenhouse Effect-Read About it


1.) a.) List three forms of radiation from the sun.

-infrared radiation

-visible light

-ultraviolet radiation


Which form of radiation from the sun has the longest wavelength? The shortest wavelength?

b.) Infrared radiation has the longest wavelength among other forms of radiation from the sun. Ultraviolet radiation has the shortest.


2.)a.) What happens to most of the sunlight that reaches Earth?

Most of the sunlight that reaches the Earth is absorbed by Earth's surface. This is about 50%.


What percentage of incoming sunlight is reflected by clouds, dust, and gases in the atmosphere?

b.)25% of incoming sunlight is reflected by clouds, dust, and gases in the atmosphere.


Why are sunsets red?

c.) Sunsets are red because its light passes through a greater thickness of the atmosphere than when the sun is higher in the sky. More light from the blue end of the spectrum is removed by scattering before it reaches the human eye. The remaining light contains mostly red and orange light. Therefore, sunsets are red.


3.)a.) What happens to the energy from the sun that is absorbed by Earth's surface?

Energy from the sun that is absorbed by Earth's surface either reflects back into the atmospere or absorbed by the land and water and changed into heat.


How might conditions on Earth be different without the greenhouse effect?

b.) Conditions on Earth might be different without the greenhouse effect because temperatures would be too cold that living oganisms wouldn't be able to survive.

Air Pressure-Read about it


1.) What is air pressure?
a.) Air pressure is the result of the weight of a column or air pushing down on an area.

How does increasing the density of a gas affect its pressure?
b.)Increasing the density of a gas affects its pressure because the more dense a gas is, the more pressure it exerts.


2.) What two instruments are commonly used to measure air pressure?
a.) Two instruments commonly used to measure air pressure are the mercury barometer and the aneroid barometer.

What units are commonly used to measure air pressure?
b.) Units that are commonly used to measure air pressure are inches of mercury and millibars.

How many millibars are equal to 27.23 inches of mercury?
c.) 922.2801 millibars are equal to 27.23 inches of mercury.


3.) What is altitude?
a.) Altitude, or elevation, is the distance above sea level, the average level of the surface of the oceans.

As altitude increase, how does air pressure change?
b.) As altitude increases, air pressure changes because it decreases. It does not have the whole atmosphere pressing down on it and there is less weight present.

What changes in air pressure would you expect if you carried a barometer down a mine shaft?
c.) I would expect the barometer column of mercury to enhance since the air pressure is pushing down on the surface of mercury in the dish. Since a mine is below sea level, the air pressure is great thus heightening the mercury in the barometer.

Wednesday, April 14, 2010

The Collapsing Can Lab


My group and I filled the soda can with approximately 15mL of water. I carefully placed the container on the Type 15500 Hot Plate and in a couple minutes we saw a cloud of condensed water vapor. We counted to thirty, then I took the prongs and turned the hot can upside-down into the bucket filled with ice cold water. Instantaneously, the can collapsed. Why did this happen? Air was forced out of the can when it started to steam. Then it was full of water vapor. Next, my group and I created low air pressure inside the container when we inverted it into the ice cold water. Thus, the can collapsed because the air pressure outside of it was stronger than the air pressure within it.