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 (輪胎) of the car before and after a short drive to see how much warmer they get from friction.
小題1:You’d better make your hands ______ to get heat when you rub them.
A. slippery                 B. dry                  C. wet    
小題2:The word “friction” in the first paragraph means “______”.
A. 摩擦                     B. 震動(dòng)                 C. 膨脹 
小題3:We can know from the passage that it’s a ______ experiment.
A. physics                  B. chemistry                C. biology
小題4:The topic of the last column (欄目) is ______
A. THINK IT OVER!           B. WHAT HAPPENED?       C. WORK WITH PARENTS.
小題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   

小題1:B
小題2:A
小題3:A
小題4:C
小題5:A

試題分析：本文是介紹摩擦是怎么產(chǎn)生的，摩擦產(chǎn)生的條件，摩擦產(chǎn)生了什么能量，以及日常生活中一些跟摩擦有關(guān)系的現(xiàn)象。
小題1:細(xì)節(jié)理解題。slippery滑的，dry干燥的，wet濕的，根據(jù)原文Make sure your hands are dry.Rub your hands together until you feel the heat of your hands.要先確定你的手是干燥的，然后把兩個(gè)手放在一起摩擦直到你感覺到手熱。故選B。
小題2:詞義猜測(cè)題。根據(jù)原文Friction happens when two things that aren’t very smooth rub together to make heat energy.當(dāng)兩個(gè)不光滑的東西搓在一起產(chǎn)生熱量，就是摩擦。故選A。
小題3:細(xì)節(jié)理解題。通過閱讀可以知道摩擦是一種物理反應(yīng)。故選A。
小題4:細(xì)節(jié)理解題。根據(jù)原文If not, ask your parents to take you out in a car.可知主題是跟父母一起共事，故選C。
小題5:細(xì)節(jié)理解題。根據(jù)原文Let’s discover friction!可知文章的主題是如何產(chǎn)生摩擦。故選A。
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