# What is a tunnel?

Tunnels are underground roads built to improve traffic . A tunnel boring machine is using used to improve the process of drilling through rock with an alternative to drilling and blasting methods.

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In this activity, we will use science and engineering skills to build a tunnel with play dough and PVC!

We first have to plan the construction of the tunnel by answering questions such as:

• The purpose of the tunnel
• The location of the tunnel
• How it will make people’s lives easier
• How we can make the tunnel aesthetically pleasing

### Materials

• PVC pipes
• Toilet paper or paper towel rolls
• Paper
• Tape
• Glue
• Paint
• 10 Popsicle sticks
• Five 10 cm lengths of wire or pipe cleaner
• Cardboard square, at least 20 cm square (for a student working surface)
• Clay ( 15 cm x 12 cm)
• Plastic spoon
• Pencil or wooden dowel
• Rulers
• Water
• Weights or heavy objects to use as weights (such as books)
• Make model clay mountains (mounds) that are ~ 12 cm high by 15 cm in diameter. Place each mountain on a piece of cardboard. Make enough for one per group.

On Day 1,  Design the procedures for boring rock out of the mountain, and build the tunnels.

On Day 2, test the tunnels by 1) pouring water over the mountains to test for cracks or openings, and 2) applying weight to test the tunnels for structural strength.

Day 1-Tunnel Design

Design and create model tunnels through clay mountains

• Make model clay mountains that are 12 cm high by 15 cm in diameter
• Place each mountain on a piece of cardboard.
• Tunnel dimensions: the tunnel must measure at least 4 cm wide by 6 cm high and go completely through the mountain.
• Use the Tunnel engineering design learned in rock cycle
• As an engineer, you are called to use the least amount of materials to complete your tunnel, for cost effectiveness. You have to estimate the volume of materials removed from the mountains by forming the remains into a shape that you can calculate the volume of (sphere, cylinder, cube)
• Ensure that the tunnel is insulated properly to avoid leaks
• Study the environmental impacts by assessing if the tunnel change the structure of the mountain

Day 2-Tunnel Testing

Test the tunnel structures for cracks (by pouring water over their structure while at a sink or over a large basin) and structural strength (by placing weights or heavy books on their mountain top).