The funnel is a cylindrical object that is used to inject liquids and pulverized substances into smaller containers at the entrance, made of borosilicate glass 3.3.The smaller tubular part of the funnel can be divided into long neck and short neck in different lengths. Funnel is an indispensable instrument in filtration experiments. When filtering, filter paper should be put in the funnel. There are many kinds of filter paper. Different filter paper can be selected according to the different requirements of filtration. Normal filter paper can be used in natural teaching. The filter paper of corresponding size should be purchased according to the size of funnel.

Usage:

1. Fold the filter paper in half for two consecutive times and fold it into a 90 degree circular corner shape.

2. Fold the filter paper, press one side three layers, the other side one layer open, funnel-shaped.

3. Fill the funnel-shaped filter paper into the funnel. The edge of the filter paper should be lower than that of the funnel. Pour some clear water into the funnel mouth to make the wet filter paper close to the inner wall of the funnel, and then pour out the remaining clean water for use.

4. Place the funnel with the filter paper on the funnel rack (such as the ring of the iron rack) for filtering. Place the beaker or test tube that receives the filter liquid under the neck of the funnel and place the tip of the funnel neck on the wall of the receiving container to prevent liquid splashing.

5. When injecting the filtered liquid into the funnel, hold the beaker in your right hand and the glass rod in your left hand. The bottom of the glass rod is close to the three-layer filter paper. The beaker mouth is close to the glass rod. The filtered liquid will flow out along the beaker mouth and then flow into the funnel along the glass rod. Note that the liquid level of the liquid flowing into the funnel should not exceed the height of the filter paper.

6. When the liquid passes through the filter paper and flows down the neck of the funnel, check whether the liquid flows down the wall of the beaker and is injected to the bottom of the beaker. If not, the beaker or rotary funnel should be moved so that the tip of the funnel is firmly attached to the wall of the beaker, so that the liquid can flow down the wall of the beaker.

Neck: short stem, long stem