Question

Make a lactometer with ballpoint refill. What would you do to make the refill stand vertically straight?

Answer 1

Hint: Archimedes principle can be used to build this mechanism. Lactometer is used to check the purity of milk. It is working with the density basis.

Complete step by step answer:
Lactometer is a device used to check the purity of the milk. It works with the Archimedes principle. In this mechanism, it measures the relative density of milk with respect to the water.

We can build a lactometer with a ballpoint refill. The following steps have to be ensured for the production.

Choose an empty ball pen refill for the lactometer.

1.) Make sure that it has a metal point.
2.) Take a boiling tube filled with water.
3.) Put the refill in the water and make sure that the metallic point is touching the water.
4.) To make the refill to stand in the water, ensure to attach a rubber piece or an eraser piece at the centre of the refill.
5.) Put a mark on the refill with a marker at which the water level is showing.
6.) Remove the water from the refill and boiling tube.
7.) Fill the milk in the boiling tube and put the refill inside the milk like the steps that we have done with water.
8.) Mark the point at which the milk level is on the refill.
9.) We can repeat these steps with the mixture of milk and water.
10.) So, we can identify easily, whether the milk is added by water or not.

Additional information:
According to the Archimedes principle, the weight of an object in the air is known as its actual weight. If the object is immersed in a fluid and the measured weight is known as its apparent weight. Buoyant force is the reason behind this apparent weight loss. This apparent weight loss will be the same of the weight of the fluid displaced by the immersed body. The buoyant force is actually an upthrust force. The actual weight of a body is also a force that acts downward. While the buoyant force acts upwards.

Note: This will work only if the refill stands vertically. So kindly ensure that you add the rubber or an eraser piece at the centre of the refill tube to make it stand vertically in the water.