Lesson 7

Density, Temperature, and Fronts

Air masses - form over different regions of land and ocean; have consistent temperatures and moisture density

Cold Fronts

• More dense because the colder it is the more compact
• Cold air masses overtake warm air masses
• Clouds along with rain form right where the differing fronts meet
• Cold air sinks below the warm air mass because it is more dense

Warm Fronts

• Less dense because warmer means expanding
• Warm air mass overtakes the cold air mass
• Clouds form below the warm air where the cold air mass is
• Rain can occur inside the cold air mass
• Warm air rises above the cold front forcing it down because it is less dense

Practice Problems

1. Hot air rises because the warmer the gas particles are the faster they move and expand so they become less dense. This means the warm air isn't as heavy so it rises.

4. Rainy cloudy and cold

Posted with Blogsy

Lesson 6

Sorry Charlie

Charles' Law

Volume is proportional to the temperature, T, in the Kelvin scale

Formula:

k is the proportional constant that indicates how much the volume of gas changes per degree of Kelvin.

This means that you can find a change in volume that comes with a change in temperature

ex: a balloon contains 300 mL of air at 285 degrees Kelvin so at 300 degrees, what will be the volume? To find this we first need to find the constant k. Using the formula, take the volume 300 divided by temperature 285 to get about 1.05 so k=1.05 mL/K. Next we have to figure out the volume of the ballon at 300 degrees. Now using the formula, multiply the constant 1.05 by the temperature 300 to equal 315. The answer is V=315 mL.

Since we learned that when gas is heated up the particles inside move fast and gain more momentum causing expansion, this results in a change of volume. The volume increases meaning the density decreases, which is why hot air rises.

Practice Problems

2. If you have the proportionality constant k then you can multiply it by the temperature to find the volume.
5. 261 degrees Kelvin

Posted with Blogsy

Lesson 4 & 5

Thermometers & Absolute Zero

There are a few different ways to scale something's temperature. Many thermometers contain a type of liquid like alcohol or mercury.

Differences in temperature cause changes in volume


There are particles that make up substances for example liquids, and these particles are moving around in random but determined paths in the liquid. They move at steady paces bumping off of each other and the container, but the speed of the particles can change causing the changes in volume.

• Gases that are heated expand

- the particles are heated and start moving faster and faster with more energy causing the expansion

• Gases that are cooled contract

- the particles are cooled down and they move slower with less energy in the liquid causing it to contract

Temperature of gas is the measure of the average energy of motion of gas particles.

Making a Scale to Measure Temperature

Find:

• Melting point or melting temperature - point where the substance melts or freezes. At this point a solid could melt or the liquid would freeze

ex: block of ice could melt at waters melting point or liquid water could freeze into a solid block of ice.

• Boiling point or boiling temperature - point where a substance boils or condenses. Boiling allows liquid to evaporate into gas but at the same temperature, gas can condense into liquid.

Degree - increment of temperature corresponding to one unit on a thermometer. The size of the degree depends on the temperature scale

- Fahrenheit or Celsius

Convert using the formula F=9/5(C)+32

Converting to Kelvin - K=C+273 or C=K-273

Absolute Zero - temperature 0 degrees Kelvin(K) where the volume of gas is theoretically zero

Practice Problems

3(on lesson 4). Celsius temperature scale is made around zero being freezing and 100 being boiling so it is easier to remember. Celsius can also be converted to Kelvin.

4(on lesson 5). Fahrenheit- 32degrees and 212degrees Celsius- 0degrees and 100degrees Kelvin- -273.15degrees Celsius and 373.15degrres Celsius

Posted with Blogsy

Lesson 3

Having a Meltdown

Density of Liquids and Solids

The formula to determine the density of an object is D= m/v. That's Density equals Mass divided by Volume. It can also be switched around to find mass as long as you know the density and volume and can help find volume as long as you know density and mass.

 

These three things all have a proportional relationship.

The volume of water in 1 liter of rain is more than in 1 liter of snow because snow is less dense therefore can't fit as much actual water in the same amount of volume as rain.

This carries into every phase. Every time something changes phases i.e. liquid to gas or solid or vice versa, there is a change in density.

Practice Problems

3. Snow is not as dense as ice and so ice contains a greater volume of water.

4. Liquid water will take up more volume than ice because it is not as dense as ice.

Posted with Blogsy

Lesson 2

Raindrops Keep Falling

Measuring Liquids

We measure rainfall by inches because volume is dependent on what container you measure it. Volume increases at a steady and predictable way in relation to the height of the beaker.


Proportional - 2 variables are directly proportional when you can multiply the value of one by a constant to obtain the value of the other.

Proportionality constant - number that relates two variables that are proportional to each other, represented by a lowercase k.

Ex: y=5x - the y and x are proportional to each other because one is being multiplied by the constant k(5).

Graphs of one variable is proportionate to another if the line of the two variables pass through the origin of the graph or point (0,0).

Practice Problems

4. Same volume different height.

5. No because some would overflow because they aren't as big and some like the tub would hold more water.

Posted with Blogsy

Unit 3 Lesson 1

Weather

Weather or Not

Weather - state of the atmosphere in a region over a short period of time. The result of interaction between the Earth, the atmosphere, water, and the sun.

Meteorologists look at all things like cloud cover, winds, temperature, air pressure, precipitation and the patterns and connections between them to predict the weather.

Jet stream - high level winds in the upper atmosphere

Fronts - warm: warm air moving in

cold: cold air moving in

Connections

• Precipitation correlates with low air pressure and all kinds of fronts
• Jet stream currents follow the curves and paths of temperature
• Low air pressure around warm and cold fronts
• Jet stream moves from west to east (in the US)
• Rain where there are clouds but clouds don't mean rain

Practice Problems

1. A planet needs an atmosphere, water and the sun to have weather.

3. A physical change is an alteration in the form of a substance like volume, temperature, shape, size, and pressure.

Posted with Blogsy

Unit 1 Review

This first unit was all about elements on the periodic table. What they are made up of like protons, neutrons, and electrons; how they are arranged both on groups with similar properties and by electron shells; and what they make when they combine and bond in different ways. Every element is different and makes up everything in the universe from the least complex like Hydrogen to the most reactive elements.

3. a) lithium- Li, 3, group 1, 3 protons and electrons

    b) bromine- Br, 35, group 7, 35 protons and electrons

    c) zinc- Zn, 30, transition metals, 30 protons and electrons

    d) sulfur- S, 16, group 6, 16 protons and electrons

    e) barium- Ba, 56, group 2, 56 protons and electrons

    f) carbon- C, 6, group 4, 6 protons and electrons

5. An isotope is an atom of an element with the same number of protons but different numbers of neutrons giving it a different atomic mass. The most common isotope is the one with the closest mass to the average atomic mass of that element.

Posted with Blogsy