The code has been updated to allow for multiple chunks of icebergs now, which can occur via melting and also if you draw an iceberg a certain way.
I was so impressed with the interactive Iceberger tool that Josh Tauberer (@JoshData) made that I had to modify it and add some additional features. Click here to see the original. My additions allow you to conjure up pre-made “icebergs” to see how they float and also allow some interaction. Try “poking” the icebergs you make.
Josh and I were both inspired by a tweet by Megan Thompson-Munson (@GlacialMeg).
Today I channeled my energy into this very unofficial but passionate petition for scientists to start drawing icebergs in their stable orientations. I went to the trouble of painting a stable iceberg with my watercolors, so plz hear me out.
— Megan Thompson-Munson (@GlacialMeg) February 19, 2021
You can choose between 3 different iceberg creation options:
Once the iceberg has been created, you can also affect it in a couple of different ways:
Some Math – no equations
The force of gravity (G) affects the entire body regardless of where it is or how it is oriented. If you show the forces, the red dot labeled G shows where the center of mass of the iceberg is. The blue dot labeled B shows where the center of buoyancy is. This is the center of mass of the part of the iceberg that is submerged. The force acting on the submerged part is equal to the volume of water displaced. If the center of buoyancy is below the center of gravity, then the forces will be equal and object will be in stable equilibrium. If the center of buoyancy is somewhere other than under the center of gravity, then the buoyant force will be pushing up on a different place than the gravity force and this will induce a rotation until they are directly over one another.
The code has been updated so that multiple icebergs are now allowed. Melting can separate a single piece of iceberg into multiple pieces, just as in real life. The melting process was a bit difficult to program because of the complexity of shapes that could be produced.
If you have additional suggestions for shapes or countries to add to the list or other improvements to make, let me know in the comments. Also if you are using this as a teaching tool, I’d love to hear how you are incorporating it into your curriculum.
Sources and Tools:
Check out the California reservoir dashboard.
It’s winter in California and that means the rainy season (snowy in the mountains). This year has been a relatively dry year and wanted to visualize how this year compares with historical levels for this time of year. I used data for California rainfall totals from the California Department of Water Resources. Other California water-related visualizations include reservoir levels in the state as well.
There are three sets of stations that are tracked in the data and these plots:
These stations are tracked because they provide important information about the state’s water supply (most of which originates from the Sierra Nevada Mountains). Data from the CDEC website appears to be updated at around 8:30am PST each day.
The visualization consists of two primary graphs both of which show the range of historical values for precipitation. The top graph is a histogram of water year precipitation totals on the specified date (in blue) as well as the precipitation total for the current water year in red.
The second graph shows the percentiles of precipitation over the course of the historical water year, spreading out like a cone from the start of the water year (October 1). You can see the current water year plotted on this to show how it compares to historical values. It also shows the present precipitation level and its percentile within the historical data for the day of the water year.
You can hover (or click) on the graph to audit the data a little more clearly.
Sources and Tools
On September 9th, 2020, the entire San Francisco Bay Area, we had a crazy combination of wildfire smoke and low clouds that darkened the sky and turned everything orange. At 9am, it looked like it was nighttime and at noon, it was so dark, that it looked like dusk.
Here is a plot of 8+ years of solar panel generation from our panels. If you click on the legend, you can toggle whether that data is shown. Total generation for the day was only 93 watt hours (as opposed to a summer median of 13300 watt hours, 13.3 kWh) and peak power was only 32 watts (vs a median summer peak of 2000 watts (2.0 kW)).
The solar generation was even worse than the next worst day in winter (typically when it rains all day). Clicking on the legend will toggle whether certain seasons are shown and you can view how solar generation varies by season.
Source and Tools:
A remarkable thing is happening in the United States and in other places around the world. Partly due to the coronavirus pandemic and partly due to changes in natural gas and renewable energy prices, renewable electricity is now a larger fraction of the US electricity grid than coal. As of early May 2020, the fraction of coal generation of US electricity is about 18% while renewables (hydroelectric, wind, solar and geothermal) account for nearly 20%.
For the entire year of 2019, coal accounted for about 24.2% of US electricity generation, while renewables accounted for 17%.4. And in 2018, coal was 28.4% and renewables were 16.8%. When you include nuclear (not technically a renewable resource, but zero emissions of greenhouse gases), about 42% of US electricity generation in 2020 comes from zero carbon sources, while fossil fuels make up the remaining 68%.
This is good news because renewables produce little to no pollution that contributes to urban air quality, health issues and climate change. Coal is by far the worst electricity generation source when it comes to air pollution that impacts human health and climate change. So this shift away from coal and towards renewables is very good news.
Here’s the same graph but showing instead the fraction of electricity from each source (you can hover over the graph to get daily values).
Source and Tools
CO2 emissions are the primary contributor to our current ‘climate crisis’. Because of buildup of heat-trapping nature of CO2 and other greenhouse gases in the atmosphere, temperatures are rising and weather and precipitation patterns are changing. Changes in climate will have profound impacts on both natural systems and our human landscapes.
Significant emissions of CO2 really started in the industrial revolution. This is when humans really started using significant quantities of non-renewable energy sources, mainly fossil fuels such as coal and later natural gas and oil. The increase in the burning of hydrocarbon energy sources for powering factories and transportation lead to growing CO2 emissions. The following graph shows the annual emissions of CO2 since 1750, before the start of the industrial revolution. In this period of 269 years, humans have emitted 1600 billion tonnes of CO2 (1600 gigatonnes). One incredible fact is that due to rapid growth in population and energy use per capita over time, we are emitting more and more CO2 each year and that humans have emitted as much in the last 28 years than in the 240 years prior to that.
The global median age is around 30 years old (i.e. half the people on earth were born after 1989). This means that more than half of the earth’s population has seen the global cumulative CO2 emissions double in their lifetime. Also very striking is that in my children’s lifetimes (around a decade), humanity has added nearly 1/5 of all human produced CO2 ever to the atmosphere.
Notes: Emissions are in units of gigatonnes of CO2. To convert to gigatons of carbon, another common unit of measuring carbon emissions, divide by 3.666.
Data source and Tools
Earth is known as the blue planet, because it’s covered with quite a bit of water. But do you know where all that water on Earth is located? This interactive visualization will show the various amounts of water in its many forms on Earth: Oceans, Lakes, Rivers, Ice, Groundwater, etc….
If you hover over a part of the circular, sunburst graph, it will show you the amount of water that is in each of the various forms shown. If the label for that form is bolded, you can click on it and see further subdivisions beyond that broad category. For example, if you click on Oceans, it will show you how the water in the oceans is distributed among the five main oceans on Earth. As you move towards more focused views on the graph, you can click on the center of the circle to move back out to larger categories and see the big picture again.
As you can see, most of the water on Earth is found in a salty form, and most of that is in the oceans. It can be hard to click through to see freshwater lakes and rivers, as you have to be very precise to expand the “Surface Water” wedge, when you are looking at all “Freshwater”.
Even smaller, on that same visualization, is the “Living things” wedge is basically invisible. You can further explore the details of the living things category by clicking on the button that appears on the freshwater graph.
Checking the Group Rivers and Lakes checkbox will group rivers by continent and lakes by major groups.
It is interesting to see how much water there is on Earth (about 1.4 billion cubic kilometers of water), but how little of it is non-salty, liquid freshwater at the surface (about 100,000 cubic kilometers, though that is still quite a lot) but it only makes up about 0.008% of all water on Earth. That means for every 10,000 gallons of water on Earth, only one of those gallons is freshwater in a lake or river that we can easily access.
It is also believed that there is more water deep in the Earth’s interior (i.e. the mantle) than on the surface or near-subsurface, but estimates of that are highly uncertain and are not included in this graph.
If you click out past Earth’s water to look at water in the solar system, the estimates shown in this visualization are only including liquid water and do not include estimates of ice (which I haven’t been able to find estimates of). The amount of water in living things is estimated assuming that the ratio of organic carbon to liquid water is more or less the same across all different types of living things (i.e. viruses, bacteria, fungi, plants, animals, etc.). This isn’t a great assumption but the estimates, which come from estimates of the dry carbon weight of these organisms, vary across many orders of magnitude so being off in liquid water weight/volume by a factor of two or so isn’t a huge problem.
Tools and Data Sources