Bending A Glass Tube Experiments

Glass is an amorphous crystalline solid material mainly used for decorative purposes. Glass is made into various shapes and can be bent as per the requirement too. The bending of the glass tube needs the knowledge of handling the glass against the bunsen burner. Let us know the process of bending the glass tube.

Aim:

To know the basic techniques of bending glass tubes using a simple process.

Materials Required:

• 20-25 cm long Soda-glass tube
• Bunsen Burner

Experimental setup:

Procedure:

• Hold the tube with both the hands horizontally, in flame from the bunsen burner.
• Get the point of bending of the glass with flame.
• Keep rotating the glass tube with the help of thumbs and fingers while heating so that the tube is heated and softened uniformly.
• Determine in which direction you want to bend the glass tube.
• Continuously keep the glass tube in the flame till it becomes red hot.
• Apply the gentle pressure on the glass tube where it is softened (red hot) and bend the glass tube in the desired angle.
• Remove from the flame when the desired angle is formed and the glass tube is bent.
• Cool it by placing on a glazed tile
• Glass tube can be bent into various angles as shown in the figure below.
• Proper and improper bend is also shown in the figure below.

Precautions to be taken during the experiment:

• Heat at least 4-5 cm length of the tube at the point of bending.
• Keep your face far and hold the glass tube away.
• Never bend the glass tube by force. Doing so can break the tube.

Viva Voce:

1. Why glass tube in red hot condition bent slowly?The glass will soften after heating, hence gentle pressure must be applied while bending.
2. Why is the glass tube rotated while heating?To ensure uniform heating glass tube is rotated
3. Give an example where bent glass is usedBent glass is used in the distillation process
4. What is the composition of soda glass?Na2SiO3 . CaSiO3 . 4SiO2
5. Can we heat apparatus made up of soda glass?No, it breaks on heating