Evaporation of water (Sara Wilson)


Research Question and Hypothesis

How is evaporation of water affected by containers with different surface areas?

As the surface area of the container increases the rate of evaporation will also increase as long as all containers are left uncovered and in the same room with the same humidity.

Standards

8.3.d - Students know the states of matter (solid, liquid, gas) depend upon molecular motion.

8.3.e - Students know that in solids atoms are locked into position and can only vibrate; in liquids the atoms are more loosely connected and can collide with and move past one another; and in gasses the atoms or molecules are free to move independently, colliding frequently.

Experimental Design

This is a very simple experiment that involves various different containers with amounts of liquid in them.

I used a beaker, Erlenmeyer flask, Graduated cylinder, petri dishes, etc...

Any containers can work, the more the better.

Fill them all with a recordable amount of water. It is hard to fill all the different containers with the same amount of water so you can put different amounts of water in each as long as you record the amounts.

Independent variable

The independent variable is the different containers that will be used.

We will be measuring the containers surface area by measuring the circular area where the water is filled to. We will determine the radius of the surface of the water in each container and find the surface are of each by calculation.

Dependent variables

The dependent variable is the change in water volume over time.

Water level will be measured after winter break and then again at the end of the first semester to determine the amount of water that has evaporated.

Series

We will be studying the evaporation of water as a function of surface area over time.

Constants and Controls

The containers are all open in the same place within the classroom to keep humidity and temperature constant.

We also put a couple of containers in a closed system with the top covered/airtight to make sure there is no loss of water over time.

Materials

Any container where the surface area can be measured can be used.

  • Beaker (25, 50, 2-100, 200ml)
  • Erlenmeyer flask (200ml)
  • Graduated cylinder (10ml, 2-100ml)
  • Petri dishes (1 with lid, 1 without)
Water
Ziploc bags

Procedures

  1. Create a table with all the different containers used.
  2. Fill each with a beginning amount of water.
  3. Measure the surface area at the water level.
  4. Put one of the 100ml beakers, one of the 100ml graduated cylinder and one of the petri dishes into their own ziploc bags. Leave the rest of the containers on a high shelf where they can't be knocked over.
  5. Leave them for three weeks over the break.
  6. Carefully take down the containers and measure the amount of water left in each container.
  7. Replace the water and leave for another three weeks.
  8. Take down the containers and measure the amount of water in each container.

Sample data and graphs

Evaporation Data Collection


Analysis & Conclusions

We have not collected the data yet but I will update when we do.

Photos & Movies

Include photos and movies of your longitudinal research.  Post your photos in the class photo album and your movies in your Youtube account.  Embed gadgets that allow you to see your movies and photos in this web page. 

References

USGS Guide to the Water Cycle - Specifically for evaporation

Engineers toolbox - Evaporation from water surfaces - can be used to calculate the evaporation rate given more variables like air velocity, relative humidity, etc...

U of Illinois - Evaporation - Simple animation and information about evaporation.

Teach Alive - Evaporation and water cycle information and animations.

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