So the design experiment is more targeted.
Objective: To verify the main components of egg shell.
Method steps: 1 Take a small amount of broken eggshells and put them into a test tube with a medicine spoon.
2 Remove 1-3ml of dilute hydrochloric acid with a dropper and add it to the test tube.
You'll see bubbles ~ ~ ~ That's carbon dioxide.
3 calcium hydroxide was introduced and precipitation began to form. If there are many bubbles, the precipitate will disappear.