You know that balloons must be kept away from sharp objects. They also needed to be kept away from flames. A fire can weaken the rubber and cause it to break. However, in this experiment you will find out how you can hold a balloon directly in a flame without breaking the balloon.

    Materials needed:

● two round balloons not inflated(充气的)

● several matches

● water

    Inflate one of the balloons and tie it. Place 1/4 cup of water in the other balloon, and then inflate it and tie it. Light a match and hold it under the first balloon. Allow the flame to touch the balloon. What happens? The balloon breaks, perhaps even before the flame touches it. Light another match. Hold it directly under the water in the second balloon. Allow the flame to touch the balloon. What happens to this balloon? It doesn't break.

    Why does the balloon with no water break in the flame? The flame heats the rubber of both balloons. The rubber of the balloon without water becomes so hot that it becomes too weak to resist the pressure of the air inside the balloon. However, when the balloon with water in it is placed in the flame, the water takes in most of the heat from the flame. Then, the rubber of the balloon doesn't become very hot, it doesn't weaken, and the balloon doesn't break.

    Water is a particularly good absorber(吸收者) of heat. It takes a lot of heat to change the temperature of water. On the other hand, when water cools, it gives off a great deal of heat. That's why areas near oceans or other large bodies of water don't get as cold in winter as areas at the same latitude(纬度) further inland.

    Most airlines go all out to ensure their passengers have the best possible flight experience. Now, Europe's low-budget airline, easyJet, wants to extend the positive experience beyond the plane ride with “Sneakairs”—smart shoes that allow visitors to explore new cities and towns without ever looking at a map.

    To transform Sneakairs from an ordinary shoe to a tour guide, all the wearer has to do is enter his or her desired destination into the easyJet smartphone app. A built-in GPS will determine the wearer's starting location while the Google Maps navigation(导航) tool will help chart the best route. Whenever a change of direction is necessary, the app will communicate with the appropriate shoe via the Bluetooth and cause it to vibrate(振动). For example, if the wearer needs to turn right, he/she will feel the sensation in the right shoe. Should the user miss the turn, the smart shoes will both vibrate at the same time, reminding him/her to change course.

    Visitors that wander off the suggested path or decide to take a break for a cup of coffee or a meal have nothing to worry about. The smart app will automatically determine the new location and chart out a new route, once the desired destination is reached. Sneakairs will vibrate three times to inform the user of the arrival and then go back to being ordinary shoes—until their navigation services are needed again!

    Sneakairs is certainly not the first navigation shoe in the market. However, easyJet is the first airline to offer them to passengers just as they are about to land in an unknown city. However, before Sneakairs can go mainstream, the easyJet team still needs to make some adjustments. Among the challenges that need to be addressed is the smart shoe's three-hour battery life, which is hardly enough for a tourist to catch all the delights a new or town has to offer!

    Nowadays, more people lose their jobs and the prices of goods and services steadily increase.{#blank#}1{#/blank#} But where do I start? Everything I'm paying for is necessity. There's nothing I can cut down on.

    But if you take a careful and objective look at your bills and all the “stuff” you're paying for, you actually do not need a good majority of them. I've put together 5 tips that you can follow right now to reduce your costs.

    1）Cut Back on Eating out.

    Maybe you didn't notice eating out is one of the things at your budget and you can save so much money just by reducing the number of times you eat out.{#blank#}2{#/blank#} It's so much cheaper preparing food at home and healthier too. This does not mean that you should never eat out. You can choose special days to eat out like birthdays or anniversaries.

    2）Reduce Your Electricity Consumption

    {#blank#}3{#/blank#} This will help reduce your electricity consumption. With CFLs (节能灯) you save so much on power. Also unplug appliances (家用电器) that you're not using.

    3）Cut Back on Magazine or Print Subscription (订阅费)

    Magazines are great but sometimes they come with articles that you don't really care about so you don't bother reading them.{#blank#}4{#/blank#} Review your magazine or print subscriptions to determine which ones to unsubscribe from. You can also draw out a list of topics or categories you like reading about and search for free online alternatives where you can read about the topic of your choice.

    4）Cancel Your Gym Membership or Go for a Pay-Per-Use Plan.

    Exercise is important to stay healthy. In fact, you save more money when you stay physically fit than if you are in poor health. But there are more affordable ways to keep fit, if you exercise for health's sake and no as a body builder or something.

    Exercise at home or jog around your neighborhood. If you can't work out without an exercise trainer, try searching for exercise routines on You Tube. If you want to use gym equipment, then you can convert your gym membership style to pay-per-use.{#blank#}5{#/blank#}

    Of course, you don't need to practice all of these at once, but if you are really willing to cut down on those costs, then one of these will surely come in handy.

A. Start by turning off the lights you're not using.

B. They're so simple but the results are impressive

C. As an alternative, make more home-cooked meals

D. It's time for you to take action and do something about your bills

E. That way you pay only when you come to the gym to use the equipment

F. Invest in gym equipment to cut down recurrent costs of gym membership

G These days most of the information or news is available on the Internet for free.

    When you're new to a school or campus, your smartphone will be your new beat friend. Here are four kinds of apps to help you get started in the US.

    ⒈Social media: {#blank#}1{#/blank#} You can use Facebook to communicate with various groups or people that share a common interest. Apps like Snapchat are more for close friends. Instagram focuses on photos you share. Twitter limits you to 280 character per “tweet,” or post. {#blank#}2{#/blank#}

    ⒉Ride-sharing: Need a ride?{#blank#}3{#/blank#} Then you will find out how far the nearest ride is to your location and how much it will cost to get where you want to go. The app is linked to your bank account, so you don't have to worry about carrying cash.

    ⒊Eating: Don't want to get off the couch（沙发）or move away from your desk? Order from almost any nearby restaurant, pay online, and wait for a delivery driver to bring it to your front door through Grubhub, UberEats or DoorDash. {#blank#}4{#/blank#}

    ⒋Texting/Phoning Home: College students like to communicate in groups, which makes messaging apps common on campus smartphones. {#blank#}5{#/blank#} But using apps like WhatsApp, GroupMe or Slack for calls or texts makes it cost-effective on a student's tight budget.

A. Type your destination into Uber or Lyft.

B. That's because it can help you make many friends.

C. Therefore, you learn to be brief, to the point and clever.

D. Turn to the computer for help and search for the destination.

E. And cellphone carriers may charge high fees for international calls.

F. This is great for students who don't have a car or the time to fetch food.

G. These are the big ones in the US: Facebook, Twitter, Instagram and Snapchat.

    Angel Garcia Crespo is a computer engineer at Carlos III University of Madrid in Spain. His group has invented a new way for deaf-blind people to "watch" TV. The idea for the technology grew out of previous work by his group. The team had already worked on making audiovisual(视听的) materials accessible to people with either vision or hearing disabilities. But the group wanted to help people with both challenges. So they asked some deaf-blind people what would help.

    In addition to relying on their sense of touch to communicate, deaf-blind people can also get and send information with a Braille line. The Braille system uses patterns of raised dots to stand for letters and numbers. A Braille line is an electronic machine with a changeable Braille display. Dots rise up or drop down based on the information sent to the machine.

    Now the new system changes TV signals to data a Braille line can use. "The key to the system is the possibility of using subtitles(字幕) to collect TV information, " Garcia Crespo explains. "Subtitles travel with the image(影像) and the audio in electromagnetic waves we don't see. But an electronic system can keep those waves. "

    First, a computer program, or app, pulls out the subtitles and visual descriptions from the broadcast signal. The system then combines the information and changes both into data for Braille.

    Now another app gets to work, which sends the data out to people's Braille lines on demand. "This is done in real time, in less than a second," Garcia Crespo says. This lets a deaf-blind person "watch" TV as it's broadcast. The system will work with various Braille lines, as long as there's a bluetooth connection available. Now, the system is only used in Europe, and it should soon be available in the US.

Volunteering is a great way to support an organization and make a difference in your community. It can also be an opportunity to meet new people and learn new skills. {#blank#}1{#/blank#}And what should we plan for? Here's a guide for beginners.

Step 1: {#blank#}2{#/blank#}

Do you want to help the world, or your community? Do you want to build your own skills, make new friends, and learn? Do you love what you do? Do you want to share your gifts with others or give something back? Think about these kinds of questions. That can help you to choose the right direction for your volunteer work.

Step 2: Choose an organization that is meaningful to you.

If you feel strongly about literacy (读写), for instance, volunteer at your local library or find out if there is an organization of volunteer tutors in your area. There are organizations doing all sorts of work. {#blank#}3{#/blank#}

Step 3: Start small.

If you already have a busy school life, volunteer your time for an hour or two a week, or perhaps one day a month. {#blank#}4{#/blank#}Then, if you find you enjoy the work and have more time to do it, take on more time by time.

Step 4: Get training.

If there is a training course, attend it. If not, talk to the group leaders and other volunteers about their experiences. {#blank#}5{#/blank#}

Step 5: Try not to give up.

Volunteer work sometimes involves unpleasant tasks, difficult fellow workers, busy days, or bad management. If you find your work difficult, however, try to work through it before you decide to quit.

A. Do you love to work with people?

B. But how do we go about volunteering?

C. Get to know others in the organization.

D. It is important that you choose something that you like.

E. Think about why you want to volunteer.

F. You'll pick up some good tips to make your work there more productive.

G. You might be surprised by how much you can do in even a little bit of time.