## String design, ellipses, and orbital mechanics

Here's a different and somewhat artistic way to encourage understanding of a conic section.  Participants physically build an ellipse by choosing two foci and sketching the figure through a loop of string.

While stitching an elliptical string design they puzzle about varying the foci spread and the loop length to create more extreme ellipses and are intuitively introduced to the measurement of eccentricity.

The range and meaning of eccentricity, orbit analysis, perihelion and aphelion are all part of this visual understanding of ellipses.

## Betsy Ross’s 5-pointed star + 4th of July activities

Flag of the United States from 1777 to 1795.

Click on the image above to see it larger in a new window.

In honor of Independence Day we thought it would be fun to look at one story about the first American Flag.

The rough design of the flag was drawn by a committee of George Washington, Robert Morris, and George Ross in 1776.  When approached by the committee, George Ross's niece, a respected seamstress, Betsy Ross, suggested some important changes.  One change was to use a 5-pointed star to represent each of the 13 colonies. The committee objected that a pentagram would be too hard to make. Betsy demonstrated that she could create the desired star by simply folding fabric and making just one scissors cut.  So, the design was changed.

How did she do that fold and cut?

## Coronavirus trends

Johns Hopkins University of Medicine has a team that maintains current maps and data about the Coronavirus.  They record changes and show trends of the virus activity throughout the World. Enjoy exploring the data, all of the visual mappings, and then delve into our activity.

Clicking on the image below will take you to Johns Hopkins current and interactive graphic showing where each state in the U.S. is today.

https://coronavirus.jhu.edu/data/new-cases-50-states

What can you see in this graphic?  What do you notice?  What can you infer?

## Saturday, June 20th, 2020

Sunrise on summer solstice at Stonehenge

On Saturday, June 20th, at 5:44 pm EDT, the Earth's North Pole will be tilted as far towards the Sun as it will ever be in the year.  This marks the longest day of the year in the Northern Hemisphere and the summer solstice ... a time that has been revered for centuries.

In this activity, students compare length of daylight to place latitude while studying the correlation, evaluating Excel generated formulas, and appreciating the significance of this date.

The activity: SummerSolstice2020.pdf

## Celebrating Father’s Day

Thank you Mother and Father for all of those diapers - Which is a better deal, cloth or disposable diapers?  How much did you cost your parents in diapers?  In the future how much could your kid's diapers cost?   Help students realize all that mom and dad went through in buying and changing diapers.

Students will compare the cost of buying disposable versus cloth diapers. They estimate how much they cost their parents in diapers and consider how much they will spend on diapers when they have a baby. This is a great math activity for Father’s Day or during the study of linear equations and introduction to systems of equations.

There is quite a bit of scaffolding built into the activity for students who might have limited experience with linear relationships and equation writing.  Depending on the experience of your students you might reduce the amount of work in the tables or omit some of the questions in this part of the lesson.

CCSS: 6.EE.9, 7.EE.4, 8.F.2, 8.F.4, 8.EE.8, HS.F-IF.8.B, HS.F-LE.2, HS.F-LE.5, MP7, MP8

Or check out:

Father's Day Blueberry Muffins is a short activity that asks students to change the amounts in a blueberry muffin recipe to multiples of and fractions of a ¼ cup measuring cup (multiplication and division with unit fractions).  CCSS: 4.NF.4, 4th, 5.NF.7, 5th, 6.NS.1, 6th, 7.NS.2

## What’s a payday loan? Good idea?

When you need a loan, and you're desperate for help, is this a good idea?

Students learn about this kind of loan and examine how it compares with personal loans and debt on your credit card.  They analyze final payments and what the actual annual interest rate (APR) is.