A day without a mobile phone

Cohesion and Adhesion Water molecules stick to each other as a result of hydrogen bond- ing. An attractive force that holds molecules of a single substance together is known as cohesion. Cohesion due to hydrogen bonding between water molecules contributes to the upward movement of water from plant roots to their leaves. Related to cohesion is the surface tension of water. The cohe- sive forces in water resulting from hydrogen bonds cause the mol- ecules at the surface of water to be pulled downward into the liquid. As a result, water acts as if it has a thin “skin” on its sur- face. You can observe water’s surface tension by slightly overfill- ing a drinking glass with water. The water will appear to bulge above the rim of the glass. Surface tension also enables small crea- tures such as spiders and water-striders to run on water without breaking the surface. Adhesion is the attractive force between two particles of differ- ent substances, such as water molecules and glass molecules. A related property is capillarity (KAP-uh-LER-i-tee), which is the attrac- tion between molecules that results in the rise of the surface of a liquid when in contact with a solid. Together, the forces of adhe- sion, cohesion, and capillarity help water rise through narrow tubes against the force of gravity. Figure 2-11 shows cohesion and adhesion in the water-conducting tubes in the stem of a flower. Temperature Moderation Water has a high heat capacity, which means that water can absorb or release relatively large amounts of energy in the form of heat with only a slight change in temperature. This property of water is related to hydrogen bonding. Energy must be absorbed to break hydrogen bonds, and energy is released as heat when hydrogen bonds form. The energy that water initially absorbs breaks hydro- gen bonds between molecules. Only after these hydrogen bonds are broken does the energy begin to increase the motion of the water molecules, which raises the temperature of the water. When the temperature of water drops, hydrogen bonds reform, which releases a large amount of energy in the form of heat. Therefore, during a hot summer day, water can absorb a large quantity of energy from the sun and can cool the air without a large increase in the water’s temperature. At night, the gradually cooling water warms the air. In this way, the Earth’s oceans stabilize global temperatures enough to allow life to exist. Water’s high heat capac- ity also allows organisms to keep cells at an even temperature despite temperature changes in the environment. As a liquid evaporates, the surface of the liquid that remains behind cools down. A relatively large amount of energy is absorbed by water during evaporation, which significantly cools the surface of the remaining liquid. Evaporative cooling prevents organisms that live on land from overheating. For example, the evaporation of sweat from a person’s skin releases body heat and prevents over- heating on a hot day or during strenuous activity. Adhesion Cohesion Hydrogen bonds Cohesion, adhesion, and capillarity contribute to the upward movement of water from the roots of plants. FIGURE 2–11 www.scilinks.org Topic: Hydrogen Bonding Keyword: HM60777 mb06se_cols03.qxd 5/18/07 10:47 AM Page 41 42 CHAPTER 2 Density of Ice Unlike most solids, which are denser than their liquids, solid water is less dense than liquid water. This property is due to the shape of the water molecule and hydrogen bonding. The angle between the hydrogen atoms is quite wide. So, when water forms solid ice, the angles in the molecules cause ice crystals to have large amounts of open space, as shown in Figure 2-12. This open space lattice structure causes ice to have a low density. Because ice floats on water, bodies of water such as ponds and lakes freeze from the top down and not the bottom up. Ice insulates the water below from the cold air, which allows fish and other aquatic crea- tures to survive under the icy surface.

Bums in the Attic I want a house on a hill like the ones with the gardens where Papa works. We go on Sundays, Papa's day off. I used to go. I don't anymore. You don't like to go out with us, Papa says. Getting too old? Getting too stuck-up, says Nenny. I don't tell them I am ashamed -all of us staring out the window like the hungry. I am tired of looking at what we can't have. When we win the lottery . . . Mama begins, and then I stop listening. People who live on hills sleep so close to the stars they forget those of us who live too much on earth. They don't look down at all except to be content to live on hills. They 86 Sandra Cisneros have nothing to do with last week's garbage or fear of rats. Night comes. Nothing wakes them but the wind. One day I'll own my own house, but I won't forget who I am or where I came from. Passing bums will ask, Can I come in? I'll offer them the attic, ask them to stay, because I know how it is to be without a house. Some days after dinner, guests and I will sit in front of a fire. Floorboards will squeak upstairs. The attic grum- ble. Rats? they'll ask. Bums, I'll say, and I'll be happy. Minerva is only a little bit older than me but already she has two kids and a husband who left. Her mother raised her kids alone and it looks like her daughters will go that way too. Minerva cries because her luck is unlucky. Every night and every day. And prays. But when the kids are asleep after she's fed them their pancake dinner, she writes poems on little pieces of paper that she folds over and over and holds in her hands a long time, little pieces of paper that smell like a dime. She lets me read her poems. I let her read mine. She is always sad like a house on fire-always something wrong. 84 Sandra Cisneros She has many troubles, but the big one is her husband who left and keeps leaving. One day she is through and lets him know enough is enough. Out the door he goes. Clothes, records, shoes. Out the window and the door locked. But that night he comes back and sends a big rock through the window. Then he is sorry and she opens the door again. Same story. Next week she comes over black and blue and asks what can she do? Minerva. I don't know which way she'll go. There is nothing I can do.

I'd Like to Be I'd like to be a happy clown and make everyone laugh. I'd wear big clothes, and a bright red nose, and be pleased with all I have. I'd like to be an athlete, and play basketball each day. I'd leap so high I could touch the sky, and make baskets along the way. I'd like to be a gardener and grow healthy things to eat. I'd plant my seeds, water them, and pull weeds. My garden would be hard to beat. I'd like to be a mermaid and swim in the deep blue sea. The fish and whales could tell their tales, while dolphins sang to me. I'd like to be a cowboy and ride horses every day. And then at night, I would tie them tight and feed them lots of hay. I'd like to be a dancer and twirl and jump and fly. I'd wear fluffy skirts and fancy shirts. People would clap as I danced by. I'd like to be an artist and try to paint the land. I would paint the water blue and the great skies, too. The ground would be the color of sand. I'd like to be a pirate. I would have to be brave and bold. I would sail with a crew on oceans of blue to look for treasure and gold. I'd like to be an astronaut and fly up to the moon. In outer space, I'd find a place to eat without a spoon. I'd like to be a zookeeper and care for birds and snakes. I'd give them food, and watch their moods, and on birthdays give them cakes. I'd like to be a musician and play songs every day. I would play the trumpet, or guitar and strum it, making music my own way. The moral of this lesson is to be what you can be. Dare to dream, and listen to your talents to find what you will be.

Of the 7 billion people on Earth roughly 0:02 6 billion own a cell phone which is 0:05 pretty shocking given that only 4 and2 0:07 billion have access to a working toilet 0:09 so how are these popular gadgets 0:11 changing your body and brain If you're 0:13 looking down at your phone right now 0:15 your spine angle is equivalent to that 0:17 of an 8-year-old child sitting on your 0:19 neck which is fairly significant 0:21 considering people spend an average of 0:23 4.7 hours a day looking at their phone 0:26 this combined with the length of time 0:28 spent in front of computers has led to 0:30 an increase in the prevalence of myopia 0:32 or nearsightedness in North America in 0:34 the 1970s about one quar of the 0:36 population had myopia where today nearly 0:39 half do and in some parts of Asia 80 to 0:41 90% of the population is now nearsighted 0:44 and it can be hard to put your phone 0:46 down take for example the game Candy 0:48 Crush as you play the game you achieve 0:50 small goals causing your brain to be 0:52 rewarded with little bursts of dopamine 0:54 and eventually you're rewarded in the 0:56 game with new content this novelty also 0:58 gives little bursts of dopamine and 1:00 together create what is known as a 1:01 compulsion Loop which just happens to be 1:04 the same Loop responsible for the 1:05 behaviors associated with nicotine or 1:07 cocaine our brains are hardwired to make 1:10 us novelty seeking and this is why apps 1:12 on our phones are designed to constantly 1:14 provide us with new content making them 1:16 hard to put down as a result 93% of 1:19 young people aged 18 to 29 report using 1:21 their smartphone as a tool to avoid 1:23 boredom as opposed to other activities 1:26 like reading a book or engaging with 1:27 people around them this has created a 1:29 new term nomophobia the fear or anxiety 1:32 of being without your phone we also see 1:35 a change in brain patterns Alpha rhythms 1:37 are commonly associated with wakeful 1:39 relaxation like when your mind wanders 1:41 off whereas gamma waves are associated 1:44 with conscious attentiveness and 1:46 experiments have shown that when a cell 1:47 phone is transmitting say during a phone 1:49 call the power of these Alpha Waves is 1:52 significantly boosted meaning phone 1:54 Transmissions can literally change the 1:56 way your brain functions your smartphone 1:58 can also disrupt your sleep the screen 2:00 emits a blue light which has been shown 2:02 to alter our circadian rhythms 2:03 diminishing the time spent in deep Sleep 2:06 which is linked to the development of 2:07 diabetes cancer and obesity Studies have 2:10 shown that people who read on their 2:11 smartphone at night have a harder time 2:13 falling asleep and produce less 2:15 melatonin a hormone responsible for the 2:17 regulation of sleep wake Cycles Harvard 2:20 medical school advises the last 2 to 3 2:22 hours before bed be technology free so 2:24 pick up a book before bed instead of 2:26 course smartphones also completely 2:28 change our ability to access information 2:30 most notably in poor and minority 2:32 populations 7% of Americans are entirely 2:35 dependent on smartphones for their 2:37 access to the internet a 2014 study 2:40 found that the majority of smartphone 2:41 owners use their phone for online 2:43 banking to look up medical information 2:45 and searching for jobs so while phones 2:47 are in no way exclusively bad and have 2:50 been part of a positive change in the 2:51 world there's no denying that they are 2:53 changing us but many successful people 2:56 have now decided to take smartphone 2:58 vacations in order to increase 3:00 productivity in our new ASAP thought 3:01 video we break down the top six reasons 3:04 you should take a smartphone vacation 3:06 and how it could benefit your life right 3:08 now and subscribe for more weekly 3:09 science videos

12 Different Behaviors in Social Media 1. The Ultras – check feeds dozens of times a day. Happily, admit their obsession. (14% of Facebook users spend at least 2 hours a day on the network) 2. The Deniers – social media do not control their lives, but gets anxious when unable to access networks. (20% of Facebook users would feel anxious or isolated if they had to deactivate their accounts. 3. The Virgins – taking first tentative steps in social media (19% of British people don’t use any social networks) 4. The Peacocks – popularity contest, high numbers of followers, fans, likes and retweets. (1 out of 10 Twitter users want more followers than friends.) 5. The Lurkers – hiding in the shadows of cyberspace. Watches what others are saying, but rarely (if ever) participate themselves. (45% of Facebook users described themselves as “observers”) 6. The Ranters – mock and mid in face-to-face conversations. Highly opinionated online. 7. The Changelings – adopt completely new personality online so no one knows their real identities. 8. The Ghosts – create anonymous profiles, for fear of giving out personal information to strangers. .9. The Informers – seek admiration by being the first to share the latest trends with audiences. 10. The Approval Seekers – constantly check feeds and timelines after posting. Worry until people respond. 11. The Quizzers – asking questions allow them to start conversations. 12. The Dippers – access their pages infrequently, often going days, of even weeks without posting.

Related quizzes

Related quizzes