1. Collective teaching activities are divided into four categories: observation and cognition activities, experimental operation activities, scientific discussion activities and technical operation activities. The reason for this distinction is that there are indeed different learning objects and learning methods in children's science education activities: some mainly use observation to understand the characteristics of things; Others mainly explore the laws of things through hands-on operation and experiments; Others make things by hand.

2. It should be noted that the actual teaching activities are often complicated and diverse. The models provided here are typical and simple, and teachers can learn from these models for vivid and rich re-creation in practice.

3. Observation is the most important way for children to know things. When guiding children's observation, teachers should pay attention to: using the remarkable characteristics of the observed object to stimulate children's interest in observation. Children often have the desire to observe and explore new things, and teachers can use this feature to attract children's attention to the observed objects and inspire them to observe. Guide children to observe through enlightening questions. Teachers should control the direction of children's observation, grasp the depth of observation, and guide children to observe comprehensively, systematically and orderly.

4. Guide children to use a variety of senses to perceive the characteristics of things. In scientific observation, teachers should try to inspire children to use a variety of sensory observation, see, listen, taste and touch. Guide children to combine observation with operation, observe things comprehensively and understand the changes of the observed objects. Children should be encouraged to express their findings in words.