MEDFORD, Ore. — We know that keeping your kids entertained during school shutdowns can be challenging which is why we have put together a step by step easy-to-do dew experiment.
What is Dew?
You know how sometimes when you walk outside in the morning and the grass is wet but it hasn’t rained. What happened? It’s dew, dude!
Water can take three different forms, solid (ice cubes in your drink), liquid (water from a tap), and gas (steam from a shower).
All air contains water in a gaseous form called water vapor. The amount of water vapor in the air depends on the barometric pressure and air temperature. Warmer air can hold more water vapor whereas cooler air holds less water vapor.
Dew point, is the temperature at which the air can no longer hold all the water vapor it contains.
Once the temperature drops near or to the dew point, water from the air will condense and form droplets on cooler surfaces. The actual dew point varies depending on air pressure and humidity. If the dew point drops below 32 F, the dew will turn into frost.
During the day, the sun’s rays are beaming down onto Earth and heat up the ground. This is called radiant heating. But at night, especially on a clear night with no clouds, the absorbed heat will escape dropping the temperature near the ground. If the temperature reaches the dew point, water vapor in the air begins to condense and tiny water droplets begin to form on cooler surfaces like a car, patio furniture, or grass.
Here's how you can mimic that same process at home using readily available materials :
Materials:
1. 1. 2 drinking glasses
2. Tap water
3. Ice
4. Paper towel
5. Timer (stovetop timer or phone timer)
Process:
1. Fill one of the glasses with water
2. Fill the second glass with ice, then add enough water to cover the ice
3. Dry the outside of each glass with the paper towel
4. Allow the glasses to sit undisturbed for 15 minutes in an area without a draft (this is important)
What happened?
The outside of the glass of water without ice remains dry, but the outside of the glass with icy water is covered with tiny water droplets.
Why? Remember what I mentioned before about how cooler air holds less water vapor. The ice water cools down the glass and surrounding air. This lowers the amount of water vapor that the surrounding air is able to hold, thus causing water droplets to condense on the glass. BOOM, SCIENCE!
Send us photos of you and your family trying out this experiment!
