Thursday, 31 October 2013

scribe post, mini hover craft and observation!



  First we looked over and reviewed our scribe post so we can improve them and get a better grade. 

                                                                                                                                                                   


Afterwards, we learned a little about mini hover craft. We also saw a example of a mini hover craft made with a ballon and a CD. I learned that mini hover craft includes air pressure (high and low), force and friction. After observing it I noticed that by spreading weight over a greater area, you can reduce the amount of force required to lift it per area. I also realised that it is related to water rockets that we studied earlier, because they both require friction. I thought this was interesting because it moved very smooth and faster than I thought.



If you want to make your own mini hover craft, here is a link for how to make them. http://www.youtube.com/watch?v=1jRK5vG3tkc






We took some quiz to review what we knew.

What are the quantities, units and measuring devices for fluids?

Task Quiz: Individually, fill in the following table in your taskbook.
Orange = answer

#
Quantity (symbol)
Units (symbol)
Measuring Devices
ex)
Pressure (P)
Pascals (Pa)
  • Barometer
  • Pressure Probe
1
Volume (V)
liters (L)/ milliliters (mL)
  • measuring/graduated cylinder
  • beaker
  • measuring cup
  • flask
2
Mass (m)
grams (g)
  • electronic scale
  • balance (scale)
3
Density (P)
gramsmilliliter(gmL)
  • volume measuring device ex) beaker
  • mass measuring device ex) scale 
4
Temperature (T)degrees Celsius (c) /
fahrenheit (F)
  • thermometer
  • temperature probe


What are the relationships between quantities?
Task Quiz 2: Imagine a quantity of gas.  Fill in the blanks with increase/decrease/stays the same.

  1. Write down predicted relationship between volume and pressure.
Imagine: a balloon pops.  
  1. As the volume increase, the pressure ____decreases_____.
  2. As the volume decreases, the pressure ____increases_____.

  1. Write down predicted relationship between volume and density.
Imagine: When water freezes and becomes ice, its volume increases.
  1. As the volume increase, the density ___decreases______.
  2. As the volume decreases, the density ___increase______.

  1. Write down predicted relationship between volume and temperature.
Imagine: Gas is let out of a ball, bike tire, or tank.  The volume of the gas increases.  Does it feel cool or hot?
  1. As the volume increase, the temperature ____decrease_____.
  2. As the volume decreases, the temperature ___increase_____.


                                                                                                                                                                   








Continuing last weeks observation, we worked on group task 2. 
We came up with a lot of answers. I think every group had great observations.


GroupTask 2: Scientists from one laboratory will share their deductions with scientists from other laboratories.
  1. Pass your deductions to another group.  Rotate counter-clockwise.  
  2. Each person will take a turn reading a deduction.  That person will also be the writer.
  3. Every person in the group will evaluate the deduction.  Thumbs up means they agree




#
Method
Qualitative Observations
Possible Deductions
1
Look closely at the dry ice.
  • mist/cloud was coming off the ice
  • it’s solid that gets smaller over time
  • there’s no presence of liquid
  • there were crystals forming on the ice
  • it sometimes vibrates
  • it’s white; it’s not transparent like regular ice
it’s subliming (changing from a solid directly to a gas)
water vapour is crystallizing on the dry ice (because the dry ice cools and freezes the water)

2
Quickly touch the ice.
  • it burns/feels very cold/numbing of the finger
  • it sticks to my finger a little bit
the temperature difference is so great (-80 for the dry ice and about 25 for you finger) that it freezes your cells
any moisture/water on your finger freezes and sticks the ice to your finger.  
3
Push the flat edge of the knife into the ice.
  • after you touch the knife to the dry ice, it gets wet and the water is cold
  • it vibrates a high pitched noise for awhile and then it stops
  • ice seems to form on the other side of the knife
the knife cools and moisture from the air condenses on the cool knife.  
the knife is close to the ice, it heats the ice and the ice sublimes.  the gas pushes up against the ice causing it to vibrate
ice seems to form on the other side of the knife
4
Push the ice along the try.
  • it slides without pushing it
  • see a gas coming off of it
  • the mist stays in the tray
  • it got stuck sometimes when being pushed

5
Breathe on the dry ice.
  • more mist/vapor comes off of it
  • it has no odor

6
When the ice gets smaller, put it into a flask, add some water, and put a cork on top.
  • the cork flies/pops off of the flask
  • the flask fills up with mist/vapor/cloud
  • bubbles formed
  • some of the mist quickly escapes between the cork and the flask

7
Put your dry ice in the fish tank full of water.
  • misty gas rising through the water
  • the dry ice sinks
  • lots of bubbles produced
  • sometimes bubbles form on the surface and then pop
  • when the bubbles pop, mist comes out of it

8
Put a graduated cylinder full of water upside down on top of a piece of dry ice.  
  • water left the measuring cylinder
  • the cylinder filled up with gas from the dry ice.











#
Method
Qualitative Observations
1

  • Observe the ice in general → mist like substance is coming off the solid
  • there are crystals on the sides of the solid
2
Quickly touch the ice.
  • It’s very cool.
  • It burns if you hold it for a short length of time.
3
Push the flat edge of the knife into the ice.
  • high-pitched noise
  • knife cools down
  • water condenses on the knife
4
Push the ice along the try.
the ice moves smoothly without slowing down quickly
5
Breathe on the dry ice.
visible vapour is in the air
6
When the ice gets smaller, put it into a flask, add some water, and put a cork on top.

7
Put your dry ice in the fish tank full of water.

8
Put a graduated cylinder full of water upside down on top of a piece of dry ice.  











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