How Can I Make a Water Purifier to Remove Salt?

A solar still uses the sun's rays to remove water impurities.

A solar still is an effective water purifier that will remove salt from saltwater. Saltwater is harmful to human health because it is high in salt. In fact, water from the sea is 3.5 percent salt. The salt is removed from the saltwater to create safe and drinkable water. Solar stills use the sun’s rays to heat the water and remove the impurities, such as salt. A solar still can be used as part of a science project or in survival situations to create drinkable water.

Things You'll Need

• Saltwater
• Plastic or glass container
• Drinking glass
• Plastic wrap
• Tape

Instructions

1. Place saltwater into a plastic or glass container that is at least 1 ½ feet wide. Put an empty glass into the container, and ensure that the top of the glass is below the top of the container. The top of the glass should be higher than the saltwater.

2. Stretch the plastic wrap across the top of the container. Tape the plastic wrap to the container to make the container airtight. Place a stone or weighted object on the plastic directly above the glass that is inside the container.

3. Place the container onto a windowsill that receives direct sunlight or outside in the sunshine. Leave it in the sun for seven to eight hours. The solar still purifies water by using the sun’s rays to heat the water so it evaporates and turns into a gas. When the gas rises, it reaches the plastic wrap and turns back into water. The water droplets will roll off the plastic and into the glass within the container. Salt does not evaporate and it will remain at the bottom of the container.

4. Remove the glass from the container. Allow the water to cool before drinking it.

References

• Teachers’ Domain: Solar Still Part 1 Salt Water
• Hyperphysics: Seawater