10/5

          This week our labs were focused on density and how we can find other variables with it. Our first lab was where we tried to measure the density of gas. The first test run,  in order to find the mass of the CO2, we measured the mass of the glass jar, the sheet of glass, and the mass of the water after its displacement (after we measured the mass of the glass jar+sheet of glass+water+CO2 we emptied the water into a beaker, of which we previously had measured the mass, and found the mass of the water) We then took the total mass of the jar, the sheet, the CO2, and water and subtracted the mass of the jar, the sheets of glass, and water to get only the CO2........ we calculated a gain in mass... we were very confused.... and our second experiment proved the same......

        We also had a quiz where we had to calculate the thickness (h) of a thin sheet of aluminum foil and a thick sheet. We knew the density of aluminum is 2.7g/1cm3. In order to find the height we used the equation m/L*W*H=2.7g/cm3....... First we measured the length and width of the thick sheet of aluminum (L=19.2cm, W=9.8cm), then we found the mass (m=1.16g) then we inserted them into the equation          1.16g/(19.2cm*9.8cm)h=2.7g/cm3        we cross multiplied and divided and came up with h=.00228cm      

      Then we took the measurements of the thin sheet of aluminum foil..... L=18.60cm, W=13.90cm, m=0.7 and density=2.7g/cm3  We inserted this data into our equation 0.71g/(18.60cm*13.90cm)h=2.7g/1cm3 and after cross multiplying and dividing got h=.00102 (we only received an 18/20in this quiz due to our confusion with significant digits)

If one substance has a greater density than another substance and they are combined, the one with the GREATER DENSITY WILL SINK (water has a density of 1g/mL)

9/28
As this is a new type of learning resource, devised from my past and future thoughts, I am going to record everything we have worked on/that I have learned/what I remember during the past couple weeks of school. The first week of school was dedicated to mass and changes in mass. We did a series of experiments: 1-We took a piece of steel wool and measured its mass. We then pulled it apart to at least double the size of the original ball and measured its mass again to see if it had changed. 2- We took an ice cube and placed it in a beaker with a watch glass over the top of the beaker (so we wouldn't lose mass through condensation), and measured its mass. After the ice cube had melted we measured it mass once again. 3- We also took a beaker 2/3 full of water and 1/8 tsp sugar and measured their mass, We then combined the two and after the sugar dissolved measured their mass once more. After all of our experiments, although there may have been changes in mass recorded, the class determined that any fluctuations were due to human error (ex: during the steel wool experiment some people didn't pull it apart over the paper letting little bits fall to the floor, consequently losing mass).

Mass and weight are not the same things. No matter where you are, your mass will stay the same (even if you are on a different planet). But, weight is determined by the amount of gravity. You could weigh 100 lbs here and weight much less on a different planet because of the amount of gravity.

 In an experiment the material in a system may change state or rearrange (physical or chemical?), but the mass stays the same until you gain particles from the surroundings.

This was displayed during an experiment. We took a ball of steel wool and held it with tongs over the Bunsen burner. Previously we had measured the mass and after we had heated it/"burnt" it we measured the mass once more. A majority of the class observed an increase in mass and we determined that because the steel wool was exposed to an uncontrolled environment during its time over the Bunsen burner particles were added/fused to the steel wool. By adding particles, we, in turn, added mass. Which led to our next revelation....

           Everything is made up of particles. Particles have mass. Mass takes up space, which means it has volume.

This last week we have touched on the meaning of density. We completed an experiment where we had two different substances, the grey and the silver. First we measured the mass of each of the different sized cylinders. We then took a graduated cylinder and filled it with water. We measured the mL of water and then slid the different sized cylinders in. We calculated the displacement each time, which was the volume of the cylinder, and recorded our data in a graph. We found that although the volume of the cylinders may be the same that the mass was greater in the silver substance than it was in the grey substance. Thus making the silver substance denser.

Density= mass/volume, density is the amount of mass for every unit of volume (mL=cm^3)

We also read an article on significant digits. We determined that you could only estimate one digit while estimating a measurement. Also that zeros can be place holders.

In making a measurement read all readable numbers using the tool and estimate 1 digit past.

We also discovered the following things through experimentation and class discussion.

Chemical Changes: A new substance is formed. The reaction gives off some form of energy: light, sound, color, and also gas (bubbles) or there's the formation of a new solid.

Physical Change: It is still the same substance (Ex: if you rip paper, it is still the same substance. The particles are just in a different arrangement)