- Laundry line
- 4 clothes pins
- Laundry basket
- Washing machine
- 6 cotton shirts
- Start by washing the shirts. You may need to ask an adult to help you, but don't worry -- they won't mind if it's all for the sake of clean clothes and science.
- Once the shirts are washed, put four in the laundry basket. Leave the remaining two in the washing machine. They will be your first test group.
- Hang up the laundry line outside. You can use fences or tree branches to secure each side of the line. If you're having trouble finding the perfect spot, ask your adult.
- Use the clothes pins to attach two of the shirts on the line. The clothes pins should hold each shirt from its sleeves. Make sure the shirts are spaced out enough so that each can flow freely in the breeze. This is your second test group.
- Take your last two shirts and layer them, one on top of the other.
- Fold these two shirts in half.
- Drape this folded shirt sandwich on the line. You're finished setting up your third and final test group.
- Think about the three different methods you have used to dry your shirts: two shirts are in the cool, damp washing machine, two shirts are hanging in the breeze and two shirts are nicely folded and draped on the line. Can you name at least one thing about each method that will help the shirts dry? What about one thing that will not help? Write your thoughts in your notebook.
- Now take a look at the "problem" for this project. Using your notes, which test group do you think will dry the fastest? Write your guess, or hypothesis, in your notebook.
- Time for waiting. To collect the best results, you should leave all the shirts alone for at least two hours.
- Bring your laundry in, but be careful to keep each test group completely separate. In other words, do not let the shirts from the washing machine tough the shirts on the line or the folded shirts.
- Use your finger to test each test group. Which one is the driest?
The shirts from the second test group will be the driest.
Fabric dries faster when it is in a warm, airy environment. The shirts in the washing machine were surrounded by the damp, cool air from the last cycle of washing. That's why they were still wet when your checked on them. The reason the shirts in the third test group were also damp -- even though they were outside -- was because you folded them. The folds pressed the wet layers of fabric against each other, preventing the warm air from doing its drying job.
Next time you need to dry your clothes, consider drying them on a clothes line! If it's a sunny, hot day outside, your shirts and pants will be just as cozy and warm as if you had put them in the dryer. And one more benefit? Drying clothes outside saves energy!
You're just getting into the good stuff with laundry science; don't stop now. Do you think certain colors of clothes dry faster or slow than others? What about different fabrics? Keep guessing and testing ways to dry laundry faster and save energy at home. You'll be happy you did -- and so will your family!