Have you ever rubbed your hands together when they get cold? Why do we do that? We do that for friction. Friction happens when two things that aren’t very smooth rub together to make heat energy. The faster you rub two things together, the more friction (and heat) you can make. Let’s discover friction!

WHAT YOU’LL NEED: ● Soap           ● Water          ● Your hands! WHAT TO DO: 1. Make sure your hands are dry. 2. Rub your hands together until you feel the heat of your hands. 3. Now, use soap and water to get your hands very slippery (滑的). 4. Try to make friction happen while your hands are slippery. 5. Please write down what has happened. LET’S TALK! Friction is an energy that happens when two things rub together. When friction happens, it makes heat! When your hands are slippery, they won’t make very much friction and your hands won’t get so hot. DID YOU KNOW? 1. Friction happens when you stop your fast running bike. 2. Ancient people made fires by rubbing two pieces of wood together. Friction happened though they didn’t know it.         ?        Friction is everywhere. Have you ever noticed situations where friction is happening? If not, ask your parents to take you out in a car. If it is not too hot, touch the tires (轮胎) of the car before and after a short drive to see how much warmer they get from friction.

根据表格内容，选择正确答案。
小题1: You’d better make your hands                 to get heat when you rub them.

A．slippery

B．dry

C．wet

D．smooth

小题2: What does the word “friction” in this text mean in Chinese?

A．摩擦

B．冷却

C．膨胀

D．震动

小题3:                        is NOT an example of friction.

A．Bike riding

B．Car driving

C．Hands rubbing

D．Friction discovering

小题4: What’s the last column (栏目)?

A．THINK IT OVER!	B．WHAT HAPPENED?
C．EVERYDAY ACTION:	D．WORK WITH PARENTS!

小题5:This text is most probably                         .

A．a science report	B．a car advertisement
C．a rubbing introduction	D．a chemistry programme

Have you ever rubbed your hands together when they get cold? Why do we do that? We do that for friction. Friction happens when two things that aren’t very smooth (光滑的) rub together to make heat energy. The faster you rub two things together, the more friction you can make. Let’s discover friction!

WHAT YOU’LL NEED:
★Soap                ★Water           ★Your hands
WHAT TO DO:
★Make sure your hands are dry.
★Rub your hands together until you feel the heat of your hands.
★Now, use soap and water to get your hands very slippery (滑的).
★Try to make friction happen while your hands are slippery.
★Please write down what has happened.
LET’S TALK!
Friction is an energy that happens when two things rub together. When friction happens, it makes heat! When your hands are slippery, they won’t make very much friction and your hands won’t get so hot.
DID YOU KNOW?
★Friction happens when you stop your fast running bike.
★Ancient people made fires by rubbing two pieces of wood together. Friction happened though they didn’t know it. ___  __?         Friction is everywhere. Have you ever noticed situations where friction is happening? If not, ask your parents to take you out in a car. If it is not hot, touch the tires (轮胎) of the car before and after a short drive to see how much warmer they get from friction.
小题1:You’d better make your hands ______ to get heat when you rub them.
A. slippery                 B. dry                  C. wet    
小题2:The word “friction” in the first paragraph means “______”.
A. 摩擦                     B. 震动                 C. 膨胀 
小题3:We can know from the passage that it’s a ______ experiment.
A. physics                  B. chemistry                C. biology
小题4:The topic of the last column (栏目) is ______
A. THINK IT OVER!           B. WHAT HAPPENED?       C. WORK WITH PARENTS.
小题5:The main idea of the passage is ______.
A. how to discover friction     B. how to rub your hands       C. how to make fires by rubbing   

Have you seen Avatar？It’s a popular movie this year. It is three-dimensional(3D), so you may have to wear a special pair of glasses to see it. The 3D glasses make the images(图像) from the movie look like they are coming straight at you.
More and more 3D movies are coming to theaters. 3D TV sets have been produced in Japan now. Three-dimensional technology can make TV and movies more exciting. But people with eye problems may get headaches if they spend too much time watching 3D movies.
When we look at an object(物体), each eye sees it at a different angle(角度). Our eyes send the two images to our brain(大脑), and the brain puts them together. That’s how we see depth(深度). So when we watch a 3D movie, one film projector(投影机) projects a left eye image and the other projects a right eye image. 3D glasses allow us to see a different image in each eye.
There are a lot of people walking around with very less serious eye problems. Under normal situations, the brain can adjust to their eyes so they can see things normally.
But when they are watching a 3D movie, the images projected to their eyes can’t be put together by their brain. So the brain needs to work harder at reading the images. That makes it easier for these people to get headaches.
Dr John Hagan, an eye doctor in Kansas City, said some people who do not see depth normally cannot see in 3D at all.
小题1:When people want to watch a three-dimensional movie, they need          .
A. a ticket                  B. a pair of 3D glasses             C. an earphone
小题2:Three-dimensional technology uses         film projector(s) to project one movie at the same time.
A. one                     B. two                         C. three
小题3:According to the passage, if we look at an object by only one eye, we can’t judge the       excatly.
A. image                   B. angle                         C. depth
小题4:Which statement is TRUE according to the passage?
A. In the near future, people can enjoy 3D movie by watching TV at home.
B. Whenever you wear a 3D glasses, you can see objects more clearly.
C. People who have something wrong with their brain can’t read the images of 3D movie.
小题5:The main idea of this passage is            .
A. how to use 3D glasses to watch a 3D movie.    
B. 3D glasses make the movie seem alive
C. not everybody can enjoy 3D movies.