david webb presentation

this week, david and jone webb came to visit.
they taught us about vacuums and air pressure.
the vacuum machine popped balloons, crushed soda cans, and made a chewy marshmallow.
this is how it works: if all the pressure and air molecules are removed from inside the can, the pressure from outside is still pushing it, so it crushes.
if pressure from outside is removed than the object will get bigger, like for the balloon and marshmallow , because air molecules inside are still pushing out.
their presentation really helped me out on understanding vacuums.
the electric and hand pump was real cool.
i want one.

pressure and temperatures

this week i took the energy test.
i thought it was very very hard!
we also did a lab called The Pressure of Gases.
there were lots of stuff in this lab, like a balloon in a bottle, and eyedropper in a plastic beaker, and a cracking soda can.
we had to draw the moving molecules in the packet.
another lab that we did was based on Gay-Lussac's Law: P vs T, at constant.
in that lab we measured the temperature and pressure of room temperature water, warmer water, hot water, very hot water, and hot oil.
we had to make a graph afterwards.
today is a minimum day!
YEH!

equilibrium

this week we did a packet on equilibrium.
the following monday is the test on energy.
we have to use the formula Q=mcΔT.
we also learned about exothermic and endothermic energy.
to learn about activation energy, we watched a Molecules in Action, a video.
the lab we did this week involved phase changes.
i have to play games and study now.

heat, energy, and elephant tooth paste

we got a new packet this week.
it was about heat and energy.
we also did a lab involving the 3 different phases of water: gas, liquid, and solid.
first, we got a piece of ice and putted it in the beaker.
then , we started heating it up until it became liquid, then gas.
we had to measure the temperature every minute for 15 seconds.
the temperature increase then decreased a little then increase.
it was not very stable.
we made elephant toothpaste!
i forgot what it was made from. but the result was some very hot yellow foam.
it cooled down fast though.
that was about it for this week.