Chemical reactions (化学反应) make for some great experiments. You can make use of the CO₂ (carbon dioxide) given off by a baking soda and lemon juice reaction to blow up your balloon!

★Balloon

★About 40ml of water (a cup is about 250ml so you don’t need much)

★Soft drink bottle

★Juice from a lemon

★1 teaspoon of baking soda

★Before you begin, make sure that you pull the balloon long to make it as easy as possible to blow up.

★Put the 40ml of water into the soft drink bottle.

★Add the baking soda and mix it with water.

★Put the lemon juice in and quickly put the balloon over the mouth of the bottle.

If all goes well, then your balloon should inflate (膨胀)! Adding the lemon juice to the baking soda creates a chemical reaction and produces CO₂. The gas rises up and escapes through the soft drink bottle. It doesn’t, however, escape the balloon, pushing it outwards and blowing it up.

Linda is reading something about how to keep healthy on the Internet. Good sleep is important for your health. You need eight hours’ sleep a night. Don’t eat or read in bed. Go to bed at the same time before midnight and get up at the same time every day. For more information, please visit www.thesleeping.com. How often do you exercise? If you want to stay healthy, try to exercise for 30 minutes a day, three or four times a week. For more information, please call Health Line at 180-2000. Studies show that flu virus (病毒) can live on our hands for a long time. So you should wash your hands often with soap. For more ways to keep the flu away from you, please call Health Line at 180-1313.   Brush your teeth twice a day and see a dentist at least once a year. The oral examination (口腔检查) is not for the health of teeth, but of the whole body. Please visit www.mydr.com for more information.