What it shows
Water dries by evaporation, turning into invisible vapour. Heat and wind make this happen faster.
The science
Water on the cloth gains heat and its smallest bits turn to invisible vapour and mix with the air. This is evaporation. More heat gives water more energy to evaporate. Moving air carries the vapour away so more can leave. That is why clothes dry faster on a sunny, windy day.
Materials
Cost: free. Many items come from home or from waste; spare parts such as LEDs, motors and wire are in the store.
- Three small handkerchiefs of the same size (free)
- Water in a cup
- A clothes line or string
- A clock
- A sunny spot, a shaded spot and a place with a fan or breeze
- Paper and pencil
Safety
For this project: An adult must help when using a fan. Keep floors dry.
Never use mains electricity: power models with cells, batteries or a low-voltage adapter. Sharp and hot tools, flames and lab chemicals need an adult or your teacher beside you. Keep magnets, button cells and small parts away from young children, and wash your hands after making.
All the safety rulesStep by step
8 steps. Do them in order, and test each part before you go on to the next. Write what you notice in a notebook as you go.
Dip the three handkerchiefs in water and squeeze each by the same amount.
Hang one in the sun, one in the shade and one in the breeze of a fan.
Note the starting time on your paper so you can work out how long each one takes.
Feel each cloth every ten minutes and write if it is wet, damp or dry.
Write the time each cloth becomes dry.
Order them from the fastest to the slowest to dry.
Make a bar chart of the drying times on paper.
Explain where the water went and say how you know.
What you should see
The cloth in the Sun with moving air dries first, and the cloth in still shade dries last.
Viva questions
A teacher or a judge will ask how it works. Try to answer each question before you open it, then compare.
1What is evaporation?
Water turning into vapour in the air.
2What makes it faster?
Heat and wind.
3Where did the water in the cloth go?
Into the air as vapour.
4Why do clothes dry fast in summer?
It is hot and often windy.
Take it further
Try spreading a cloth wide and folding it, and see which dries first.
Change one thing, measure what happens, and add a table or chart of your readings: that is what turns a model into your own investigation.
Free ebooks for this project
Science projects
Easy Science Projects for Class 1 to 5
Simple, safe projects young children can make with a little help
Science projects
Earth, Space and Geography Models
Solar system, seasons, eclipses, volcanoes and the water cycle explained