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Using a StoryUsing a Story Sink or Float:Sink or Float: Moses in the Moses in the
NileNile Pharaoh gave the command to kill all
male babies born to the Israelites by throwing them into the Nile river.
Yoheved could not bear to obey the command. She chose to hide her baby at home.
After 3 months he was too difficult to hide. The family was in danger!
YohevedYoheved’’s conflicts conflict::
Throw the baby to the Nile
Hide the baby at home
Protect the baby
Protect the rest of the
family
Protect the whole
family
Assumptions: the baby cannot swim.Assumptions: the baby cannot swim. the baby cannot float on the water.the baby cannot float on the water.
The Injection:The Injection:
Put the baby in a box that Put the baby in a box that can float on the watercan float on the water
How to build the box?How to build the box?What materials can float What materials can float
on water?on water?
We ask:
Step 1: Present a Step 1: Present a phenomenonphenomenon
Float or sink:Float or sink: Take different objects and assume
which will float and which will sink.
as example, we have here: candle, oil, paper, skewer, Styrofoam ball, Plasticine, plastic pipe.
Step 1: Present a Step 1: Present a phenomenonphenomenon
Check the assumptions by experiment.
The candle, skewer & Styrofoam ball are floating.
The plasticine & plastic pipe are sinking.
The paper floats, and then sink.
Step 2: explain the Step 2: explain the phenomenonphenomenon
The object is full with air
The object is floating on the
water
The concept: Density
The ratio between weight and volume The density of water is 1 g/ml
Why?
The object’s density is less
then 1
Step 3: changing a Step 3: changing a parameterparameter
How can we make a sinking object float?
How can we make a floating object sink?
We add weight to the
Styrofoam ball
The ball will sink
The object’s density is more
then 1
Step 3: changing a Step 3: changing a parameterparameter
How can we make a floating object sink?
We block the pipe with plasticine
The pipe will
float
The object’s density is less
then 1
Step 3: changing a Step 3: changing a parameterparameter
How can we make a sinking object float?
We put oil on the paper
The object’s density is less
then 1
The paper will
floatThe oil is getting to the small holes instead of the air
and prevent absorption of
water
Step 3: changing a Step 3: changing a parameterparameter
How can we make a sinking object float?
Back to the InjectionBack to the Injection::
Take the baby and put it in a box made of papyrus
The baby will float on the water
Coat the box with tar
The baby will safely float for long time
The object’s density is less
then 1
The tar prevents
absorption of water
Thank YouThank You!!Dr. Rami Kallir
+972-46380422+972-52-2786758
