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Phy Science Mid Term
Apologia Phy science Modules 1-8
Question | Answer |
---|---|
Mass | metric system = grams; English system = slugs |
Distance | metric system = meters; English system = feet |
Volume | metric system = liters; English system = gallons |
Time | the metric and English unit is seconds |
(1) milli | 0.001 (liters, meters or grams) |
(1) centi | 0.01 (liters, meters or grams) |
(1)kilo | 1,000 (liters, meters or grams) |
A student measure the mass of a rock to be 14,351 grams. What is the rock's mass in kilograms | 14,351 g/1 X 1 kg/ 1,000 g = 14.351 kg. So 14,351 grams is the same as 14.351 kg. (See pg 12&13 for more detail) |
The length of a tabletop is measured to be 37.8 inches. How many cm is that? | 37.8 in/1 X 2.54 cm/1 in = 96.012 cm (the conversions will be given to you but you need to know how to use them - ref pg.14) |
For practice on unit conversions, go to page 14&15 and do the On Your Own Problems 1.3 - 1.8 | don't look at your previous answers - re-work the problems! |
Understand concentration (pg.17) If two cleaners have the exact same active ingredient, why can one be a more powerful cleaner than the other? | the more powerful cleaner would have a higher concentration of the active ingredient. |
Understand Relative Humidity (basically how much water vapor the air can hold) Would water evaporate more quickly on a humid day or on a dry day? | on a dry day because there is little water vapor in the air so water can evaporate quickly. But if the air became completely saturated with water, no evaporation could take place. |
How does sweat cool you down? | The process of evaporation requires energy. As the sweat (water released onto your skin) tends to evaporate, it takes energy (in the form of heat) away from your skin. When energy (heat) leaves your skin, it gets cooler. |
Understand the greenhouse effect. What it does and why it is important. (Fig 2.4, pg.33) | It's when certain gases (water vapor, carbon dioxide, methane) trap heat(in the form of light) that radiates from the earth, allowing it to warm the atmosphere and keeping it at a temperature (50oF) that is near perfect conditions to maintain life |
What is the composition of dry air? | 78% nitrogen, 21% oxygen, 1% other gases |
What makes up the majority of the air we inhale | nitrogen |
What makes up the majority of the air we exhale? | nitrogen |
What is the next gas that we exhale the most of? | oxygen |
Review Figure 2.9 on pg.47. which shows the concentration of air pollution levels from 1975 to 2002. The government made regulations on fuel and how it is burned. What was the result? | These figures show that every air pollutant examined has a lower concentration today then it did 30 years ago, meaning today’s air is cleaner than 30 years ago due in part to some government mandates. |
What does the ozone layer do? | Understand that ozone in the ozone layer blocks harmful ultraviolet light from reaching the earth and ozone is constantly being produced from the earth’s supply of oxygen |
Is ozone good for us, bad for us, or both – and why? | ozone is a poison – so we must reduce or eliminate the ozone near the earth’s surface. Ozone is a good thing in the ozone layer, but it is a pollutant at ground level because that is where we breathe. |
Atmospheric pressure is the pressure exerted on earth by the atmosphere, measured in atm's. A weather report will show this pressure either in pounds per square inch or inches of mercury. **Know how these numbers relate. (see pg.59&60 for more detail) | When the atmospheric pressure is 1.0 atm, it would be reported as 14.7 pounds per square inch or 29.9 inches of mercury. Don't memorize these numbers - just understand that they mean the same thing, just different ways of reporting. |
OYO 3.2 - If the atmospheric pressure were 1.1 atm. Which of the following values for atmospheric pressure would you see in the weather report: 29.9 inches, 32.9 inches, or 28.1 inches? | 1.1 atm is above sea level so the inches or pounds would have to be higher than the average of 29.9 inches. It would therefore have to be reported as 32.9 inches because that is the only one that is higher. |
What are the regions in the homosphere from lowest to highest? | troposphere, stratosphere, mesosphere |
What are the regions in the heterosphere from lowest to highest? | thermosphere and exosphere |
What gases make up the homosphere? | 78% nitrogen, 21% oxygen, 1% other gases |
What gases make up the heterosphere? | oxygen, helium, hydrogen |
What region(s) in the homosphere does temperature decrease with an increase in altitude? | troposphere and mesosphere |
What region(s) in the homosphere does the temperature increase with an increase in altitude? | stratosphere (due to the ozone layer) |
What region is called the “weather layer” and why? page 62 | the troposphere, because this is where almost all weather phenomena occurs |
Understand that when you heat something up you are adding energy to it which is picked up by molecules. When they absorb this energy, they begin moving faster. What do molecules do at lower temperatures? | move slower |
Polar vortex is a weather phenomenon that only happens in the fall over Antarctica where winds blowing around the South Pole prevent warmer air from entering which results in extreme low temperatures. How does this affect the "ozone hole"? (see pg.70) | this “hole” is caused by ozone-destroying agents called CFC’s which work only in the presence of the Polar Vortex, which lifts them up to the stratosphere. The “ozone hole” gets deeper during the fall but remains unchanged the rest of the year. |
Know how to read a chemical formula. If the letters are abbreviations for the individual atoms that make up that compound, what does the little subscript numbers mean? What does it mean if there are no numbers? | Each subscript number stands for the quantity of that particular atom that is in that compound. If there is no number, than there is only (1) atom. Do OYO 4.2 - 4.4 for clarity |
Polarity occurs when you have opposite charges within the same structure. With the comb experiment, the water bent toward the comb but the oil didn't. Which was polar? | Water is a polar molecule. The negative charge on the comb (from your hair) attracted the positive charges on the hydrogen atoms in the water causing them to point toward the comb. |
Why didn't the comb in the polarity experiment affect the oil? | Vegetable oil is made up of nonpolar molecules. These molecules do not have polarity (meaning the electrons are shared equally). As a result, they are not affected by electrical charges |
Polar substances will dissolve only substances made of polar molecules or ions and nonpolar substances will dissolve only nonpolar substances. Water does not dissolve gasoline. Is gasoline most likely made up of ionic, polar or nonpolar molecules? | gasoline is made up of nonpolar molecules. Water is polar and can only dissolve polar molecules. |
hydrogen bonding | the bond that brings molecules close together, linking them (see diagram 4.5 on pg.92 for clarity) |
In solid form, the molecules in a substance are closer together making it more dense. Why than is ice able to float on water? | Hydrogen bonding keeps water molecules close together but only in liquid state. When water is solid, its molecules must stay in a certain arrangement requiring them to be apart – making solid water (ice) less dense than water and able to float. |
Where is the vast majority of earth’s water supply? | it's contained in the oceans as saltwater |
Where is the vast majority of earth’s freshwater supply? | it is stored in icebergs and glaciers. |
Where is the largest source of liquid freshwater? | groundwater |
All water on this earth picks up salt from the rocks and soils that is passes over. Why aren't rivers salty? | Salt water dumps into the ocean but only water evaporates in the hydrologic cycle leaving the salt behind. In lakes and rivers that have outlets, the water & the salt is exchanged with other sources never allowing the salt to concentrate. |
What does the amount of salt in the ocean have to do with the age of our planet? | The amount of salt in the ocean now is not nearly salty enough if the earth were really billions of years old – thus the salinity of the oceans tell us that the earth is very young. |
Where do glaciers come from? | They start on mountains covered by snow year round, as new snow falls, the old snow underneath gets packed down into firn. The weight of the ice and snow gets so heavy it slowly starts to slide down the mountain and move across land. |
Where do icebergs come from? | they come from glaciers (they are the edge of the glacier that has advanced to the ocean and breaks off (called glacier calving) and forms the iceberg |
Understand what adiabatic cooling is … | it is the cooling of a gas that happens when the gas expands with no way of getting more energy |
Name the 5 distinct sections of the earth. | atmosphere, hydrosphere, crust, mantle, core |
What is the main thing scientist observe to study portions of the earth they cannot see directly? | they study seismic waves which are generated by earthquakes and travel through the earth eventually reaching the surface |
What causes the magnetic field of the earth? | the large amount of electrical current (or flow) in the earth’s core |
Describe briefly the 2 theories that try to explain where the electrical current in the earth’s core originates. | Dynamo theory says the motion of the core is due to temperature differences in the core and the rotation of earth. Rapid Decay theory says the electrical current in the core started as a consequence of how earth was formed and is reducing over time. |
Which theory is more scientifically valid? | the rapid decay theory is more scientifically valid since it is most consistent with data |
Why is the magnetic field on earth so important to us? | it deflects harmful cosmic rays emitted from the sun that would otherwise hit the earth and kill all life on the planet |
What is Pangaea? | a hypothetical super continent that might have existed in the earth’s past |
What are the 4 types of mountains? | fault-block, folded, volcanic, domed |
What are the 4 basic groups of clouds? | cumulus, stratus, cirrus, lenticular |
What are the 3 main factors that affect earth’s weather? | thermal energy, uneven distribution of thermal energy, water vapor in the atmosphere |
What does insolation stand for? | incoming solar radiation |
What season is the Northern Hemisphere having at aphelion? | summer |
What season is the Northern Hemisphere having at perihelion? | winter |
What causes wind? | temperature differences (this causes the air to circulate in a loop, rising and falling) |
What are the 4 basic types of weather fronts? | cold, warm, stationary, occluded |
What type of weather can a cold front bring? | a violent rainstorm and cooler temperatures, lasting only a few hours |
What type of weather can a warm front bring? | a long, light rain, warmer temperatures, lasting less than a day |
How long does a single thunderstorm cell last? | the mature stage of a typical thunderstorm cell lasts no longer than 30 minutes, but a thunderstorm can consist of several thunderstorm cells. |
What are the stages of a thunderstorm? | cumulus, mature, dissipation |
What causes lightning? | positive charges on the ground attract negative charges in clouds, forming a STEPPED LEADER. The closeness of negative charges forces the positive charges up, making the RETURN STROKE which is responsible for most of the light and sound of the strike. |
What causes thunder? | thunder comes from the super heated air traveling out from the lightning bolt in waves. Our ears detect these sound waves as the loud sound of thunder. |
What are the 2 types of lightning and briefly describe them? | CLOUD-TO-GROUND lightning forms the lightning bolt which hits the ground. CLOUD-TO-CLOUD lightning, also referred to as “sheet lightning” is between clouds and never hits the ground. |
How does a tornado form? | Tornadoes are formed from cumulonimbus clouds – because the strong updraft of a thunderstorm cell is required to form the vortex. |
Understand how hurricane's form and what effect's their rotation | they begin as thunderstorms over tropical seas. Warm moist air is lifted up and winds begin to rotate along the low-pressure pocket. In the Northern Hemisphere they rotate counterclockwise and in the Southern Hemisphere, clockwise due to Coriolis effect |