Moses on the Nile

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

kallir@netvision.net.il