December 3, 2018

## Three parts

1. Experiment
• If possible, we will do an experiment
• You need your cellphone’s camera
2. Genomic databases
3. Planets

## Free fall

• I will drop an object in front of the class
• The screen will show a timer
• You must record the experiment with your cellphone
• In your computer, open a new text file and write the experimental data
• three columns: seconds, position, and replica
• one row for each time the object crosses a mark
• Send your text file to andres.aravena+cmb@istanbul.edu.tr

## Example videos

YouTube has an option to show the video at 0.25 speed. Try that also

## Genomic databases

Every time a researcher publishes a paper about DNA sequencing, all the sequences are uploaded to several databases.

One of these databases is https://www.ncbi.nlm.nih.gov/sra/

We want to understand how fast this database is growing

## Database growth

• The growth of databases is usually modeled as a semi-log linear model.
• Build a semi-log model and find
• what is the factor of growth per day?
• What will be the database size two years after the last entry in your table?

## Planets

The file planets.txt contains the astronomical data for the planets in our solar system. The columns are:

• Name of the planet,
• Diameter in km,
• Distance to the sun in km,
• AU: distance to the sun in astronomical units, and
• Period of the orbits in days

We want to find the relationship between Period and Distance

## Steps

• Download the file planets.txt
• In the same Rmarkdown document as the previous question, create a new section
• Draw three plots
• One using normal scales
• One using semi-log scales
• One using log-log scales

## Steps

• Based on the 3 plots, decide which is the best approach to use a linear model. Explain why you made that decision.
• Build the model and show the coefficients
• Compare your result with Kepler’s third law

## Bonus

• Looking at the log-log plot, do you think that there is something missing?
• Find the Distance and Period for the “missing planet” between Mars and Jupiter

## Delivery

You should send two files to andres.aravena+cmb@istanbul.edu.tr

• The text file with the first part
• The Rmarkdown file with the second and third part

You can send the files in a single email or in two separated ones

Put your student number in the subject

Enjoy!