1. Understand the changes caused by iodine sprinkling and starch, and know some common starchy foods in daily life.

2. In the process of hands-on experiments, take the initiative to find problems, explore practice to find answers, and cultivate children's hands-on ability.

Activity preparation:

1 .courseware 2. Iodine sprinkling, potatoes, vegetables, steamed bread, apples, pens and recording paper. 3. Wordpad, red flag, some activities:

〉〉〉〉〉〉〉〉〉〉〉〉12: What does Binbin look like? Why?

2. The teacher briefly introduced the function of starch.

(2) Children guess 1. Show the recording paper and guide the children to identify the food in the recording paper one by one.

2. Let the children guess which foods contain starch.

3. Guide children to record their guesses on the recording paper.

4. Share your own guess.

< 3 > experimental verification 1. Show me the iodine shower. The teacher told the children in a mysterious tone that this was "divine water".

2. Lead the children to record the color of "Shenshui". It is brown.

3. Introduce that "Shenshui" will turn dark blue when it meets starch.

4. Children experiment and record the experimental results.

< 4 > exchange discussion 1. Introduce your own experimental results.

2. The teacher checks one by one according to the child's introduction.

< 5 > Game: Find 1. Show courseware: Guide children to guess which foods contain starch?

2. Click on the courseware: verify one by one. 3. Match 1: See which group found more starchy food?

Introduce the rules of the game; According to the courseware and food, each group discusses and writes the guessing results on the clipboard. Which group guessed better, put a red flag. Play the game * * * four times, which group of flags will win.

B children's competition extension: when iodine is sprinkled with starch, it sometimes turns black and sometimes turns bright. Why?