Water for the World: Desalination

Since the Earth is known as the Blue Planet, you would think there would be more water than we could ever need. However, almost all of the water on Earth is saltwater and cannot be drunk. Luckily, saltwater can be turned into fresh, clean, water through desalination. Desalination can work in many ways, but the cheapest version is a simplified version of distillation. The salty water evaporates onto a sloped piece of plastic wrap and drips into a funnel, now as freshwater. With only a container, a funnel, and some plastic wrap, you can reduce the salt content of water by up to 200x.

Supplies:
12 Clear Plastic Containers

12 Small Plastic Cups

12 5ml Funnels

Thermometer/Weather App

Plastic Wrap

Tape

Saltwater (½ cup water, 1/20 cup of salt)

4+ Black Paper

4+ Tinfoil Sheets

4+ White Paper

Camera

Drill

Hot Glue Gun

Super Glue

24+ Fishing Weights

Syringe

24 Bricks

Step 1. Drill a hole in the middle of each container.

Step 2. Place a funnel into the hole, with the funnel facing towards the top.

Step 3. Shoot hot glue onto the bottom of the funnel, so it sticks in place.

Step 4. Once the hot glue has dried, put superglue on top of the hot glue.

Step 5. Place plastic wrap over the container. Make sure it can create a slight slope.

Step 6. Tape around the edges of the container except for a corner so you can pour the water in.

Step 7. Pour ½ cup of saltwater into the container.

Step 8. Tape the corner. Make sure the entire container is sealed.

Repeat these steps as needed.

Step 1. Over a small plastic cup, place plastic wrap.

Step 2. With the funnel, poke a hole in the plastic and the center of the paper.

Step 3. Place the device outside, elevated on bricks. Put weights in the center of the plastic wrap.

Step 4. Place the cup underneath so the water from the device will go into the cup.

Step 1. Remove cup from device.

Step 2. Place syringe into cup and take water out.

Step 3. Note how much water was in each cup.

Step 4. Replace cup.

If things go wrong, use this helpful guide.

• All of your water gets evaporated.

Just refill the problem device.

• Your devices get lost.

Make a new device if you have enough supplies.

If not, exclude the device from your future data.

• It rains and your cups fill up.

Remove that day from your dataset.

• A device stops producing water.

Take the device down and rebuild it. If it still doesn't work, check for leaks. If all else fails, make a new device.

Hopefully, these can help you.

My experiments show that Black is overall the best color of paper to use because it produces over 2x the water that the 2nd best color, White, makes. Of the 4 colors, Clear, White, Tinfoil and Black, almost half (46%) of the water was made by the Black containers. The worst one to use is Clear. Of two cups of saltwater, Clear only made 0.15 cups (34.6 mL) of water. Surprisingly, the reflective tinfoil did not do well. It may have been because the tinfoil reflected sunlight away from the container. Overall, more water was produced in extreme temperatures (above 80 and below 65), and most of the containers produced more water when it was sunny. Strangely, the clear containers did not conform to any of the average trends. The black, white, and tinfoil made more water in hot temperatures, but the clear made more in cold temperatures. Most devices made more in hot and sunny environments, but the clear had consistent results in cold and rainy/cloudy. Even though this experiment was not to see how much water I could produce, it was still fun to see that small plastic containers with paper could make a total of 207.35 mL of water. If I were to continue this experiment, I would probably find a new location for the desalinators as climbing on the roof every day isn’t the safest activity. I would also continue the experiment for more days to get more data.