Experiment: Hot Air balloon

19/09/2008 (Friday)

a) Which is stronger?
* The wind or the sun?
JN, LX, J : The wind.
Others : The sun.
JN : It makes us feel cold……..like today.
ZYg : The hot sun will make us feel very hot…… and dark too!
* We read a story about “The Sun and The Wind”.
* These two good friends decided to play and see who is stronger.
* They experimented a man.
* The wind blew with all its might…..and the man was chilling and shivering.
* When it was the sun’s turn, the man had to fold his sleeves and took off his jacket. The sun used all his might and finally the man had to jumped into a river for a bath.
T : So, for hot air balloon, which do we need……..hot air or only wind?
Class: hot air.
* They learnt that a slight blow of wind would help to smoothen the hot air balloon’s flight. Stong wind will be dangerous for it.

b) Poem: The Wind
I can’t see you Mr. Wind,
But I know you are there,
You are bending the trees,
And blowing my hair.

* We recited and had various body movements. At this stage, the kids could understand without Chinese translation.

c) ZY’s encyclopedia
* LX brought a medium-sized hot air balloon lantern to school similar to mine. She was very excited about it. They have 4 threads connecting the balloon to the basket.
* However, actual balloon requires different number of ropes to connect its parts.
* They learnt that the hot air will make the balloon float. When they want to go higher, they increase the burner’s flame. To board down, the pilot can pull a rope to open the top part of the balloon to discharge some hot air. Otherwise, he can reduce the flame. With this knowledge, we started our experiment.

d) Experiment: hot air balloon
* materials needed: plastic bag, some threads, cellophanetape, a hairdryer.
* We wanted to do at the garden but withdrew due to the wet weather.
* Kids were divided to 3 groups.
* they tied the 4 threads onto the open part of the plastic bag. Thus, it would be easier for them to hold onto the flying plastic bag later.
* Next, I switched on the hairdryer and blew them. They were in joy to fell the blowing hot air.
* I blew the cool air in the plastic bag. The plastic bloated and just floated and was really messy.
*Max suggested we use a basket to hold the plastic bag. Thus the threads were tied to the basket.
* This time, it bloated more nicely. We were not satisfied.
* We looked at our hot air balloon lantern sample. There is a hole thus it definitely can’t fly. Zy said we closed the hole.
* We used some plastic to cover the hole.
* It flew a little bit only…….Why?
JN : Too heavy.
EG : We should use more hairdryers.
T : Okay, only Le Xin brought a hairdryer. Next week, we will try again with more
hairdryers.
* The class agreed.