How to Make Salt Water Denser

Salt makes water denser.

Knowing how to make salt water denser is a good skill to have in physics class, especially for the units on buoyancy and density. The process is simple, and there are multiple methods. Depending on which method you take, the process may take anywhere from a minute to a few days. Also, you may also need to choose the method depending on the volume needed at the end of the process.

Things You'll Need

• Salt
• Water
• Paper cups
• Scissors
• Plastic wrap
• Heat source
• Glass container

Instructions

Decrease Volume, Increase Density

1. Cut the sides of a paper cup into strips and wrap the cup with the plastic wrap. Hook the center of the wrap to the inside of the bottom of the cup.

2. Place the cut-up cup with wrap upside down over a cup of salt water.

3. Set the project in the sunlight. The water will evaporate and drip off the outside of the cup. The leftover water inside will be more dense.

Alternative Methods

1. Boil the salt water in a glass container. The more you boil it, the denser it gets.

2. Add salt. The more salt you add to the water, the denser it gets.

3. Add denser water. Salt water that has been made less dense can be made more dense by adding denser salt water.

References

• University of Illinois at Urbana-Champaign Physics Department; Ask the Van Q & A: Salt's Effect on Water's Density; Jason; July 2006