Science Smarts: How do puddles disappear?

By Patty Rooks on April 24, 2021.

I do believe that spring is finally arriving! This week we’ve had a bit of nice weather followed by a little rain and snow (which I am welcoming with open arms!).

Despite it being so terribly dry recently, I do have a few puddles in my yard. I don’t care how old you are, who can resist a good puddle when you have your rain boots on? I know I cannot! Of course, when there is something different in my yard, I am asked a lot of questions such as how do puddles disappear? Of course, this has to do with science so … let’s investigate!

Remember to ask an adult before doing this experiment

Materials

– Food colouring

– Tap water

– Glass

– Spoon

– 3 plastic sheet protectors

– Marker

– Pipette or medicine dropper

– Fan

– Masking tape

– Sunny location

– Cool location

– Flat work surface

– Sunny location

– Cool location

– Normal room

Procedure

– Find a good sturdy table to work at.

– Label the three sheet protectors as follows: Sunny location; Windy location; Cool location

– Fill the glass about ¾ full of tap water.

– Set on the table. Add 20 drops of food coloring to the water – I know this sounds like a lot, but we want a really dark colour. Stir well. You want the colour to be quite dark.

– Fill the pipette with the coloured water. Randomly place a few drops of the water on the first plastic page protector until there is no more water in the dropper. Go crazy and draw a few deigns!

– Repeat with the other two page protectors.

– Set the fan up in a room away from sunlight and not too cool.

– Take the “cool” page protector to this location. You will want to tape it down so it does not blow away!

– Turn on the fan.

– Place the “sunny” page protector in the appropriate location.

– Repeat with “cool.”

– Observe every 10 minutes.

Which location dries up the fastest?

Why?

What is going on?

Which puddle dried up the fastest? Slowest? The science here is due to evaporation. The “puddles” you made on your paper (and outside) disappear due to evaporation. Evaporation in scientific terms is the process in which water turns from a liquid to a gas or vapour. The puddles dry up due to evaporation.

While precipitation (rain, snow and hail) and condensation (water droplets collecting on a cold beverage glass) can be seen with the human eye, evaporation is much less visible a process and often harder for younger scientist to understand. With the coloured water, you can see the evaporation process and what does or does not speed up the rate of evaporation.

Hope you had fun! Next time, take your investigation outside if at all possible and investigate with real puddles! I know I will.

Patty Rooks, Senior Scientific Consultant PRAXIS, “Connecting Science To The Community”. Contact Praxis at praxis@praxismh.ca, http://www.praxismh.ca, Tweet or follow us @PraxisMedHat, or friend us on Facebook. Address: #12 826 11 Street S. E., Medicine Hat, Alberta, T1A 1T7 Phone: 403.527.5365, email: praxis@praxismh.ca.

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