1. Flowers that will change color: Fill a cup with the same amount of water, drop a few drops of food pigment into one cup, put the flowers in transparent bottles respectively, and observe the color change of the flowers after a few days. Scientific knowledge: Stem is one of the vegetative organs of plants, which has the functions of supporting plants, transporting water and nourishing food. The stems of plants can transport water and nutrients absorbed by roots to all parts of plants from bottom to top. The flowers in the vase will change color precisely because the stems have blue ink.

2. Balloons that ignore each other: Blow two balloons filled with gas, tie them to prevent air leakage, and connect them with thin iron wires. Scientific knowledge: Scientific experiments show that the electricity brought by friction is either positive or negative. The same electricity as the glass rod wiping wire is called positive electricity; The charge that is the same as that of rubber rod rubbing fur is called negative charge. The same charges repel each other and different charges attract each other.

3, battery family: let children observe the shape characteristics of batteries, according to the model and function of the battery classification or queuing. Guide children to choose the right battery and put it in the electric toy in the right way to make it move. Scientific knowledge: batteries refer to small devices that can generate electricity, such as solar cells. The chemical batteries we usually use can be divided into primary batteries and secondary batteries.

4, magnetic field lines: put the magnet in a plastic bag, then stir it in the sand, then take the plastic bag out and put it on a small plate, take out the magnet, and the iron filings will fall. After many times, you can get a lot of iron filings. Put the magnet on the handmade paper, spread the collected iron filings evenly around, and gently pat the handmade paper. Due to the magnetic field, the pattern of magnetic field lines will appear on the paper.