Galileo, with his numerous experiments was able to find out 2 very important things:

1. All objects, independent of their size, shape or mass fall towards the earth in the same way. This means that a feather and an elephant will take the same time to fall from the same cliff.
2. The so-called "free fall movement " is an accelerated movement, with constant acceleration. It is similar to the movement of a car accelerating on a freeway, with the difference that it is an up-down acceleration.

1. Go to the web site: http://www.explorescience.com/freefall.htm

In this page:

• Mass (kg): Mass of the ball being released by the hand above. We can adjust the mass of the ball between 0.01kg (10 grams) and 0.5kg (500 grams)
• Radius (m): radius (size of the ball). One diameter is 2 times the radius of a ball. We can have a ball as small as 0.01m radius (10 cm radius = 20 cm diameter) and a ball as large as 1m radius (2 m diameter. This is a VERY BIG ball). Unfortunately the simulation does not change the sizes in the drawing, but we can use our imagination to check it out.
• Height (m): Height from which we drop the ball. It goes from 1m to 100m.
• Wind speed (m/s): This is a tricky one. We can make downward-going wind and upward-going wind in this gameÖ The upward-going strongest wind is ó1m/s and the downward -going strongest wind is +1m/s.
• Air density (kg/m³): How "heavy" is the air or atmosphere we are playing with here? 1kg/m³ air density means that 1 cubic meter of air weighs 1 kg. 1kg/m³ is the same as 0.001g/cm³. To give you idea, waterís density is 1g/cm³ but we will not be using this buttonÖ.
• Delta t in seconds: is the size of the time intervals we look at our falling ball. We will not be dealing with it eitherÖ.

QUESTION 1: The table below describes the settings for this question.
 

Setting	Mass(kg)	Radius(m)	Height(m)	Wind(m/s)	Air Dens. (kg/m3):	Delta T(s)
1	0.01	0.01	10	0	0	0.03
2	0.5	0.01	10	0	0	0.03
3	0.01	1	10	0	0	0.03
4	0.5	1	10	0	0	0.03

What is the time it takes for the ball to fall for each one of the settings above? Record your answer below. (The time is shown next to the graph on the left.)
 

Setting	Time it takes (s)
1
2
3
4

What is your conclusion?
 
 
 
 

QUESTION 2: The table below describes the settings for this question.
 

Setting	Mass(kg)	Radius(m)	Height(m)	Wind(m/s)	Air Dens. (kg/m3):	Delta T(s)
1	5	0.01	10	0	0	0.03
2	5	0.01	10	0	1.5	0.03
3	5	0.01	10	0	3.5	0.03
4	5	0.01	10	0	5	0.03

What is the time it takes for the ball to fall for each one of the settings above? Record your answer below. (The time is shown next to the graph on the left.)
 

Setting	Time it takes (s)
1
2
3
4

What is your conclusion?
 
 
 
 
 

QUESTION 3: The table below describes the settings for this question.
 

Setting	Mass(kg)	Radius(m)	Height(m)	Wind(m/s)	Air Dens. (kg/m3):	Delta T(s)
1	5	0.30	10	0	0	0.03
2	5	0.30	10	0	1.5	0.03
3	5	0.30	10	0	3.5	0.03
4	5	0.30	10	0	5	0.03

What is the time it takes for the ball to fall for each one of the settings above? Record your answer below. (The time is shown next to the graph on the left.)
 

Setting	Time it takes (s)
1
2
3
4

What is your conclusion?
 
 
 
 

QUESTION 4: The table below describes the settings for this question.
 

Setting	Mass(kg)	Radius(m)	Height(m)	Wind(m/s)	Air Dens. (kg/m3):	Delta T(s)
1	5	0.01	10	0	0.3	0.03
2	5	0.4	10	0	0.3	0.03
3	5	0.7	10	0	0.3	0.03
4	5	1.	10	0	0.3	0.03

What is the time it takes for the ball to fall for each one of the settings above? Record your answer below. (The time is shown next to the graph on the left.)
 

Setting	Time it takes (s)
1
2
3
4

What is your conclusion?