MATERIALS
This activity demonstrates how water flow
The water flow model (includes 4 table
is affected by the particle size of different
frames and 4 plastic tubes representing
earth materials. The earth is made up of
gravel, sand, clay, and fractured
soil, rocks, dirt, sand, clay and many
bedrock)
other materials. All of these materials can
3 different sized balls in clear bottles
be different shapes and sizes and
4 watering cans
therefore the amount of space in between
1 bucket for source water
them varies. This space affects how
4 buckets to collect water
quickly or slowly the water will move
4 velcro labels for the tubes
through the ground.
Water
Make sure you have all items
before the students arrive!
York Children’s Water Festival: Activity Book
SCIENCE AND TECHNOLOGY: POROSITY AND PERMEABILITY
ACTIVITY DESCRIPTION:
BEGIN THE ACTIVITY
Make sure watering cans are filled with water before the students arrive.
Read this to the students.
Today, we are going to talk about different earth materials. Right now we are standing on
the ground. The ground is composed of clumps of various sand, gravel and clay, which all
have different textures. What does texture mean? Wait for answers.
The texture is the surface look and feel, as well as the substance of a material.
Point to materials in the different plastic tubes. What is the texture of each of these
materials? Wait for answers.
Encourage descriptions including: coarse, smooth, size of pieces/grains/particles.
Can you describe the colour and shape of the materials? Wait for answers.
Discuss the different answers the students give.
The spaces between the grains, or soil particles, are called pore spaces. Are the spaces
between the clumps all the same size? No, the smaller the grains or soil particles, the
smaller the pore space and vice versa. We can see this with this jar of different size balls.
Show the students the different size balls in the clear bottles and indicate how
they have different pore space (space between the balls). Let’s pretend each bottle of
balls is a different earth material. Can you match up which balls represent which earth
material based on the particle size of the earth material and the size of the balls? Have the
students guess which bottle of balls represents sand, clay, and gravel.
Clay has the smallest particle size, so it can be demonstrated by these marbles. Sand is the
next biggest, so it can be demonstrated using the rubber balls. Gravel is the largest
material, so it can be demonstrated using the white balls. Pay particular attention to how
the balls fit together and how much space is between them. You may notice that the smaller
the balls, the smaller the spaces in between.
Now, let’s think about this in relation to groundwater.
How does water move through each of these types of materials underground?
Can water move right through a grain of sand or gravel? Wait for answers.
No. Then how does it move underground? It moves between the grains of sand or gravel,
that is, around, under or over the particles. What are those spaces called again? Wait for
answers. Pore spaces.
York Children’s Water Festival: Activity Book
SCIENCE AND TECHNOLOGY: POROSITY AND PERMEABILITY
THIS IS NOT A SCRIPT – THIS IS A GUIDELINE
have a different material in them. These four materials are sand, gravel, clay, and fractured
bedrock. Based on the pore space and the particle size of these earth materials, can anyone
figure out which earth material each tube contains? Have 4 different students label the
velcro signs of each material onto each stand.
We are going to test out the permeability of each of the materials. Does anybody know what
permeability means? Wait for answers. The definition of permeability is: the
capability of a porous rock or sediment to permit the flow of fluids through its pore
spaces. It means the amount of water that can get through a material. What material do
you think water will move through most easily and why? Wait for answers. Let’s test it
out!
Could I please have four different volunteers come up for this demonstration?
Have the four student volunteers come to the front and stand behind the display.
Pay attention to how fast the water is moving through each material. When they are
ready, have each of the students pour the same amount of water from the
watering can into each of the cylinders. Observe the movement of water. Compare
the amount of water that made it into each of the discharge buckets underneath
the display.
Are the observations we made correct? Wait for answers. Which material was the easiest
for water to move through?
If something is permeable that means that it lets water and other liquids through it. If
permeability measures which material lets the most water through, which one of these
cylinders was the most permeable? Wait for answers. The fractured bedrock was the most
permeable because it lets the most water through the fastest.
Which of the materials had the biggest pore spaces? Wait for answers.
The fractured bedrock had the largest pore spaces, followed by the gravel and then the
sand. The clay lets water through so slowly we cannot see it in such a short time.
Does water move more easily through big pore spaces or small pore spaces? Wait for
answers. Big pore spaces. If something has big pore spaces we say it has high porosity. If
York Children’s Water Festival: Activity Book
SCIENCE AND TECHNOLOGY: POROSITY AND PERMEABILITY
Different types of materials have different sizes of pore spaces. These sealed cylinders each
permeable, what does that tell us about pore spaces and permeability?
The larger the pore spaces the more permeable the material is because there is more space
for things to move through.
Since water is able to move through soil, no matter what type, we have to be careful with
what we put onto the ground. Chemicals like fertilizers and pesticides can easily move
through the soil with the water and contaminate our groundwater. In York Region a lot of
our drinking water comes from the ground. If that groundwater was to get contaminated it
would mean we would have to work harder to make the water safe enough to drink.
WHAT HAVE WE LEARNED?
Water that is underground moves around particles sometimes very slowly. Do not
take water for granted!
Updated April 26, 2016
York Children’s Water Festival: Activity Book
SCIENCE AND TECHNOLOGY: POROSITY AND PERMEABILITY
fractured bedrock has high porosity and, from the cylinder we saw it was also the most