Transcript Pop cans, tents and bridges!

Pop cans, tents and bridges!
Miss Laverty 2012
***worksheets, experiments and lesson
adapted from the Edmonton Public
curriculum book***
Happy Monday!
1. Hand out the workbooks
2. Grab a copy of today's worksheet
3. Sit down and show me that you are ready to
“move some pop cans”
Magic Moving Pop Cans
• Challenge: use only a straw and
your breath to make the two pop
cans move towards each other
• Materials: two pop cans and one
straw
• Work with a partner to try
different ways to get the cans to
move towards each other.
Describe your strategies
Magic Moving Pop Cans
• What were your strategies?
• What worked best?
• Diagram
Magic Moving Pop Cans
• Results:
– The easiest way to get the cans to move towards
each other was to blow through the center of the
cans with the drinking straw
Magic Moving Pop Cans
• Inferences:
– When we blow through the center of the two cans,
the air is moving quickly
– Bernoulli’s principle states that the faster air moves,
the less pressure it exerts on surfaces over which it is
passing
– By reducing the air pressure between the cans, the air
pressure on the other side of the cans is now greater
than the air in between them
– This causes the cans to be pushed together by the
regular air pressure of the room
Magic Moving Pop Cans
• Real life examples:
– Wind chimes
London Bridge is falling down
• Question: how does the speed of air affect the
pressure it exerts?
• Materials: paper
• Procedure
1. Fold a sheet of paper in half to create a tent shape
2. Predict what will happen when you blow through
the tent.
3. Stand the tent up on the table and hold the corners
between your thumbs and forefingers
4. Blow through the tent
5. Record observations
Paper Tents and Tunnels
• Record a before diagram and a during diagram
• Try the tent shape and the tunnel shape
Paper Tents and Tunnels
• Inferences
– Blowing through the tent produces faster moving
air
– Faster moving air creates a low pressure area
inside the tent
– The higher pressure of the air on the outside of
the tent causes the sides to bend in
Paper Tents and Tunnels
Real life example:
• “Galloping Gertie”: a suspension bridge from
the 1940s couldn’t handle air blowing under
and over the bridge
• http://www.youtube.com/watch?v=jzczJXSxnw
Group Work
• Stay on task
• Respect the learning of everyone
• Follow instructions