Question

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

Answer 1

Lactometer

1. Lactometer is a device that is used in order to check the purity of milk.
2. The working principle of a lactometer is the specific gravity of milk and Archimede's principle.
3. The purity is checked by calculating its relative density with respect to water.

Construction of Lactometer

1. In order to construct a lactometer, we can use an empty ballpoint refill with a metallic point.
2. Insert the refill with the metallic point inside the water present in a boiling tube.
3. Insert the metallic point in a small eraser piece so that it can stand vertically up straight.
4. Use a marker to mark the point when the refill is above the water.
5. Replace the boiling water with milk in the boiling tube.
6. Insert the refill in milk and use a marker to mark the point when the refill is above the milk.
7. Now replace the milk with a mixture of water and milk and repeats the above step once again.
8. Compare all three results and estimate whether water is mixed in the original milk or not.

Hence, in order to make the refill stand vertically straight, the metallic point is inserted into a small eraser piece.