the wind is calm and there is no rain. Typhoon
usually strike(侵襲) Taiwan from June to October,
called (颱風季). According to the
wind speed, there are three types of intensity:
(輕度), (中度), and
(強度).The typhoon packs(夾帶) strong winds and
heavy rain. It is important to be well-prepared before
typhoon comes.
3. Guide students to draw typhoon intensity symbols
on the worksheet.
mild
【Production】
Experiment
T: Why is a typhoon spiral? Let’s do an experiment
to find out the answer.
1. Each group prepares tape, a scissor, and two PET
bottles before the class.
2. Guide the students to do the steps below:
(1) Remove the caps of the PET bottles, and stick
tape on the opening of one of the PET bottles,
leaving a hole with a diameter of at least 1 cm in
the middle.
(2) Fill another PET bottle with 80% of blue water.
(3) Put the two bottles together and wrap them with
tap.
(4) Spin the bottle with blue water and upside down.
(5) Imagine the blue water as the ocean and observe
the whirlpool in the bottle.
3. Ask the questions
T: What do you see in the bottle?
Ss: The blue water is spiral and it spins
counterclockwise.
【Wrap-up】
Summarize
T: The blue water in the bottle is like the ocean.