Task 2 Explore
Step 1 Read and order(基础性作业)
为完成“探寻变化的奥秘”项目，学校科学社团正在解密变化。请你将以下步骤排序。
() Shake the big bag.
() Mix the sugar and cream in a small bag.
() Put salt and ice cubes(冰块)in a big bag.
() Put the small bag into the big bag with ice cubes and salt.
() Enjoy the ice cream!
() Get some big and small plastic bags.

(6) (2) (3) (4) (1) (5)

Step 2 Predict and write(拓展性作业)
社团成员们在制作冰淇淋的过程中，对为什么要往冰块里加盐提出疑问，他们准备做实验。请你帮忙完成实验报告。
What we need(实验材料): ice cubes, salt, sugar, water, three plates, timer(计时器)
What we do(实验步骤):
1. Put an ice cube on Plate A. Add sugar to it.
2. Put an ice cube on Plate B. Add salt to it.
3. Put an ice cube on Plate C. Add water to it.
4. Start the timer. Stop the timer when one ice cube becomes water.
What we find(我们的发现): The ice cube on Plate ① melts the fastest. The ice cube is ②. When we put salt on the ice cube, it's changing into a ③.
What we learn(我们的结论): Salt makes the ice cube ④ (melt / freeze). The ice cube gets very cold, so it can ⑤ (melt / freeze) the mixture in the small bag.

①B ②water ③liquid ④melt ⑤freeze

根据实验步骤，Plate A加了糖，Plate B加了盐，Plate C加了水。结合Unit 7 How do things change中关于物质变化的知识，盐能降低冰的熔点，使冰融化更快。所以Plate B的冰融化最快，融化后变成水。盐让冰融化，冰变得很冷能冻结小袋子里的混合物。