Grace Cox (Class of 2022) - Blue Science Portfolio #3

4. What were the key tips you remembered about solving math problems in science this
year? Word problems? Provide an example from this portfolio of a science math
problem that was challenging to solve this year.

What I have learned about solving math problems in math, it to align the equal signs
throughout the problem and to write out each step and the formula for each equation. For
word problems I have learned to read them more carefully and find the most important parts
of the problems.

Example:​

•An auto travels at a rate of 25 km/hr for 4 minutes, then at 50 km/hr for 8 minutes, and
finally at 20 km/hr for 2 minutes. Find the total distance covered in km and the average speed
for the complete trip in m/s.
​Distance = Distance = Velocity • Time
Distance = 25km/hr(1hr/60min)(4min)+50 km/hr(1hr/60min)8min+20km/hr(1hr/60min)2min
Distance = 1.7km+6.7km+0.7km
Distance = 9km

Velocity = Velocity = Distance/Time
Velocity = 9000m/14min (60sec)
Velocity = 10.7 m/s

5. Which lab conclusion or sample of writing are you most proud of in this portfolio?

Isotopes Quiz Conclusion:
To find the number of neutrons in a silicon isotope there are a few steps. First you find

the atomic number which is 14 and you subtract that from the mass of the isotope. The atomic
mass of silicon is 28.08 amu. The equation will look like; 28.08 - 14 = 14.08 amu. We also did
this during the m&m lab. There were a few steps to determine the average atomic mass. In
the m&m lab, we found the individual average masses of the isotopes; Plain m&m mass: 33.1
÷ 38 = 8.7g . Caramel m&m mass: 12.5 ÷ 5 = 2.5g. Peanut m&m mass: 11.4 ÷ 5 = 2.28g.
Then we multiplied each result by its percent of abundance and added them all together to
find the average atomic mass of 118.9 amu. In the silicon there were 3 different isotopes,
different amounts of neutrons, but still with the same amount of protons. Si-27 has an atomic
mass of 27.9769 amu, meaning there are 13 neutrons in the nucleus of this isotope. Si-28 has
an atomic mass of 28.9765 amu, meaning there are 14 neutrons in the nucleus. Lastly, Si-29
has an atomic mass of 29.9738 amu, meaning there are 15 neutrons in the nucleus. In order
to calculate the average atomic mass of an element, the isotopes of the element must be
taken into consideration. The atomic mass shown on the Periodic Table of Elements is
representing an average of the atomic masses and abundances of the element’s isotopes. In
this example, Si-27 has an atomic mass of 27.9769 and a relative abundance of 92.2297%.
Therefore, 27.9769 X 0.922297 determines the mass percentage of Si-27: 25.8%. Secondly,
Si-28 has an atomic mass of 28.9765 and a relative abundance of 4.6832%, making the mass

percentage 1.36%. Lastly, Si-29 has an atomic mass of 29.9738 and a relative abundance of
3.0872%, making the mass percentage 0.925%. By adding 25.8030109393, 1.357027448,
and 0.9253511536, the average atomic mass of Silicon, 28.085 amu, can be determined. In
conclusion, the percent of abundance contributes to the average atomic mass of an element
because some isotopes occur more frequently than others, and it is important to know
whether the average atomic mass of the isotope occurs rarely or more often for accurate
results.

6. What are you excited to learn about in science next year? Do you want to pursue a
career in the sciences? Explain

I am excited to learn about biology. Life sciences interest me and I am looking forward
to learning about it in highschool. I want to study to be a marine biologist for my career. The
ocean animals and the ocean life interests me, and I hope I could study it one day.