Clouds Clouds have a big influence on weather. They are a necessary precursor of precipitation, although not all of them
produce precipitation. Clouds also prevent some solar radiation from reaching the ground and absorb some of the
heat that is re-radiated from the surface. As a result, cloudy days are likely to be cooler and cloudy nights warmer
than clear days and nights.
Water vapor condenses out of the air when the temperature reaches the dew point. Air may reach its dew point
when humidity increases or air temperature decreases. The latter commonly happens when warm, moist air rises.
For clouds to form, water vapor must condense around tiny particles called nuclei (singular, nucleus). A nucleus
might be a speck of dust or smoke, or it might be a salt crystal. The condensation of many water molecules around
a nucleus forms a tiny droplet of liquid water. If billions of these water droplets come together, they make a cloud.
Clouds are classified in several ways. The most common classification used today divides clouds into groups based on altitude

• Middle clouds form at middle altitudes and consist of ice crystals, water droplets, or both. Examples of middle
clouds include altocumulus and altostratus clouds.

• Low clouds form at low altitudes and consist entirely or mainly of water droplets. Examples of low clouds
include stratus, stratocumulus, and nimbostratus clouds.

• Vertical clouds grow upward and have their bases at low altitude and their tops at middle or high altitude.
They form when strong air currents carry warm air upward. Examples of vertical clouds include cumulus and
nimbocumulus clouds.

Questions
1. How do clouds influence weather?
2. Explain how clouds form.
3. Outline how clouds are classified by altitude

Red’s momentum vector before the collision is green’s momentum vector after the collision. question 1 options: equal to shorter than longer than question 2 (1 point) saved since green bounces off red, this must be an collision. question 2 options: explosion elastic inelastic question 3 (1 point) red transfers of its momentum to green during the collision. question 3 options: none all little most question 4 (4 points) why does red transfer all its momentum to green? back up your answer with information from the simulation. write at least 2 sentences. question 4 options: skip toolbars for . more insert actions. more text actions. more paragraph style actions. question 5 (1 point) now make red much heavier than green. answer the questions below to describe how both red and green behave after the collision. question 5 options: slowed down sped up kept the same velocity question 6 (1 point) green sped up during the collision as it question 6 options: gained momentum from red lost momentum to red maintained a constant momentum. question 7 (1 point) after the collision . . question 7 options: both green and red moved to the right. both green and red stopped as they have lost all momentum. red stopped and green moved to the right. red bounced off green and went to the left. green moved to the right. question 8 (4 points) only some of red’s momentum was transferred to green. why did this occur? back up your answer with information from the simulation. write at least 2 sentences. question 8 options: skip toolbars for . more insert actions. more text actions. more paragraph style actions. question 9 (1 point) now make red much lighter than green. answer the questions below to describe how both red and green behave after the collision question 9 options: green sped up after the collision therefore it must have gained momentum. green sped up after the collision therefore it must have lost momentum. green slowed down after the collision therefore it must have gained momentum. green slowed down after the collision therefore it must have lost momentum. question 10 (1 point) since green gained momentum, red had to have momentum because you cannot create or destroy momentum. question 10 options: gained lost kept the same amount of question 11 (1 point) since green was so much and harder to move, it caused red to bounce back to the left giving red . question 11 options: heavier . . . . positive lighter. . . . negative lighter. . . . positive heavier . . . . negative question 12 (4 points) now, click on more data at the bottom of the sim. play with different numbers for the masses and starting velocities. you can even make the starting velocities negative! tell me one thing you discovered by adjusting the speeds and masses. write at least 2 sentences. be specific and use words like velocity, momentum, mass, increased, decreased, etc. 13. true or false: when red and green collide, they stick together. question 13 options: true false question 14 (1 point) the velocity of red & green after the collision is the velocity that red started off with. question 14 options: larger than smaller than equal to question 15 (1 point) the velocity after the collision was less because the mass has question 15 options: stayed the same decreased increased question 16 (1 point) the momentum before the collision was the momentum after the collision. question 16 options: larger than smaller than equal to conclusions question 17 (4 points) how are elastic and inelastic collisions different? give two or more ways. your answer should have at least 2 sentences. question 18 (4 points) give an example of a collision in real life. use the law of conservation of energy to describe the transfer of momentum. be sure and discuss the momentum before and after the collision occurs. you will need at least 3 sentences to thoroughly answer this question.