Tp on density

Nour Kali  3i2                                                                                                      Friday 11 October

  TP on Density 

Introduction:

Density is the amount of matter in an object per unit minute. Density may be calculated trought normal means for a regular shape, but for irregulary- shaped objects scientists use what is called the displacement method. For regular shape and irregular shape we use the same formul (e= m/v). Density can be useful in identifying substances.    

The objective is to mesure the density of a marble, two rocks, a ping pong ball and a blue ball. What is the difference of density between the balls and the rocks?

I think that the marble will have a bigger density because the mass is bigger than the ping pong ball and the blue ball. But the blue ball has a bigger volum than the marble. So I think that the marble will have a bigger density after the blue ball and the ping pong ball at last.

Protocol:

To mesure the density of all the balls we have mesure the volume and the mass. We converted the cm into m and the g into kg. We use the formul ( V= 9/3 . π . R3 ) to find the volume of the balls. We also mesure the mass with a scale and after we use the formul (e= m/v) to find the density of the balls. For the rocks we add approximately 40 mL of water to a graduated cylinder. Record the volume to the nearest 0.1mL and we put the rock in the cylinder and we remesure the volum of the water to the nearest 0.1 mL. After
we subtracted the volum before we put the rock and after we put the rock in. We use the same formul ( V= 9/3 . π . R3 ) and get the volume. And we mesure the mass with the scale. After we did the same formul (e= m/v) as for the ball and we get the density. We did the mesurements 2 or 3 times for each objects and also calculated the density 2 or 3 times each objects to be sure of the result. We found that the density depend on the mass and the volum wich are independant .

[pic 1]

Data:

For the balls:

For the rocks:

Data analysis :

For the balls

Δ = uncertainty

we use the caliber to mesure the raduis of the balls and the scale to mesure the mass. There’s 0,0001kg of uncertainty for the mass and 0,05cm of uncertainty for the raduis.

Blue ball:   Δ den1= ( Δm/m + 3Δr/r)× den1        

Δ113 kg/m³ = ( Δ0,0201 kg/0,0201 kg + 3Δ3 cm/3 cm)× 113 kg/m³    

Δ113 kg/m³ = 1419.28 kg/m³           113 ± 1419

Ping pong ball:    Δ den1= ( Δm/m + 3Δr/r)× den1

Δ33kg/m³ = ( Δ0.0024kg/0.0024 kg  + 3Δ1,95 cm/1,95 cm)× 33kg/m³

Δ33 kg/m³ = 414.48 kg/m³              33 ± 414

Marble :    Δ den1= ( Δm/m + 3Δr/r)× den1

Δ2,129kg/m³ = ( Δ0,0057kg/ 0,0057kg  + 3Δ0,7cm/0,7cm)× 2,129 kg/m³     

Δ2,129kg/m³ = 26.74024  kg/m³                2,129 ± 26,74

For the rocks and the marble :

Δ = uncertainty

we use the graduated cylinder to mesure the volum of the balls, and the scale to mesure the mass. There’s 0,0001kg of uncertainty for the mass and 2,5 mL of uncertainty for the raduis.

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