Evaporation at Home: A Science Activity for Grade 5 (5-PS1-1)

The question

Where does a puddle go? It does not soak away completely. Most of it goes into the air, and a paper towel race shows what speeds it up.

A 10-minute version

You need four squares of paper towel, four plates, a measuring spoon, a clear cup and a timer.

1. Put one square on each plate. Label them still, wind, warm and covered.
2. Add exactly the same amount of water to each, about 1/4 teaspoon.
3. Leave one on the table. Fan one gently and steadily with a piece of cardboard. Put one in a warm, sunny spot. Turn the clear cup upside down over the last one.
4. Check every 3 minutes and note whether each patch is big and dark, smaller, faint or gone.
5. At the end, look at the inside of the cup.

What to notice

The fanned square usually dries first, then the warm one. The covered square stays wet longest, and tiny droplets often appear on the inside of the cup. Your times will differ from anyone else’s, so compare the order.

The science idea

Water is made of tiny moving particles. At the surface, some move fast enough to break away and float into the air as water vapor, a gas we cannot see. That is evaporation. Warmth makes particles move faster. Wind carries the escaped particles away. Under a cup the air fills with vapor, so drying slows and droplets form.

A common mix-up

Evaporation does not need boiling. Water evaporates at any temperature, just more slowly when it is cold.

Safety

Wipe up spills right away so nobody slips.

Go further

The full lesson, aligned to NGSS 5-PS1-1, is here: Where does a puddle go?