The Magic Treehouse series is a beloved collection of children's books written by Mary Pope Osborne. In one of the books, titled "Twister on Tuesday," the main characters Jack and Annie find themselves in the midst of a thrilling adventure. The story begins when Jack and Annie receive a message from Morgan Le Fay, the enchanted librarian, who tells them to find a special kind of book that will help them on their mission. Utilizing the magical powers of the treehouse, Jack and Annie travel back in time to the year 1874 to find the book they seek. Upon arriving in 1874, they discover that the town they are in is dominated by a sense of fear and apprehension. The reason for this becomes apparent when they learn that a destructive and powerful tornado is about to hit the town.
You're probably not going to notice the extra weight of this rope on a short sport climb, but you'll feel it in your pack or on longer routes.
This is great for soft catches on lead, but can be dangerous or even scary for a seconder, particularly if there are obstacles on a climb that you don t want to hit, like a block or slab. In this Perspective article, we propose that a major philosophical change would benefit this field, a proposition that is based on evaluation of situations in which rodent models have provided useful guidance and in which they have led to disappointments.
The reason for this becomes apparent when they learn that a destructive and powerful tornado is about to hit the town. Jack and Annie meet a girl named Kathleen, who takes them to her family's storm cellar for safety. While in the storm cellar, Jack and Annie learn about the devastating effects of twisters and how it is possible to predict them.
Coiling Rope in a Box
What is the longest rope length L of radius r that can fit into a box? The rope is a smooth curve with a tubular neighborhood of radius r, such that the rope does not self-penetrate. For an open curve, each endpoint is surrounded by a ball of radius r. For a box of dimensions $11\frac$ and rope with $r=\frac$, perhaps $L=\frac+\frac<\pi> \approx 1.3$, achieved by a 'U':
I know packing circles in a square is a notoriously difficult problem, but perhaps it is easier to pack a rope in a cube, because the continuity of the curve constrains the options? (I struggle with this every fall, packing a gardening hose in a rectangular tub.) I am more interested in general strategies for how to best coil the rope, rather than specific values of L. It seems that if r is large w.r.t. the box dimensions (as in the above example), no "penny-packing" cross-sectional structure is possible, where one layer nestles in the crevices of the preceding layer.
This is a natural question and surely has been explored, but I didn't find much. Edit 1. It seems a curvature constraint is needed to retain naturalness: The curve should not turn so sharply that the disks of radius r orthogonal to the curve that determine the tubular neighborhood interpenetrate. Edit 2 (26Jun10). See also the MO question concerning decidability. Edit 3 (12Aug10). Here is an observation on the 2D version, where a $1 1 2r$ box may only accommodate one layer of rope. If $k=\frac$ is an even integer, then I can see two natural strategies for coiling the rope within the box:
$\qquad \qquad \qquad \qquad \qquad$ Red is rope core curve, blue marks the rope boundary.
Interestingly, if I have calculated correctly, the length of the red rope curve is identical for the two strategies: $$L = 2 (k-1)[r \pi/2] + 2(k-1)^2 r \;. $$ For $r=\frac$, $k=8$ as illustrated, $L=\frac<7\pi> + \frac \approx 7.5$. (As a check, for $r=\frac$, $k=2$, and $L$ evaluates to $\frac<\pi>+\frac$ as in the first example above.)
- packing-and-covering
- mg.metric-geometry
- dg.differential-geometry
- open-problems
Kathleen's father is a scientist studying tornadoes, and he explains the different signs to look for when a twister is approaching. He also explains the importance of listening to warnings and taking shelter. As the tornado approaches, Jack and Annie are transported back to their treehouse, but they are determined to warn the people in the town about the impending disaster. They return to 1874 and use their knowledge to help the townspeople prepare for the twister. In a courageous and suspenseful climax, Jack, Annie, and Kathleen's family race against time to find shelter and protect themselves from the fury of the tornado. Through their bravery and quick thinking, they are able to escape harm and ensure the safety of others in the town. "Twister on Tuesday" is a captivating story that combines adventure, history, and science education. It not only engages children with its thrilling plot and relatable characters but also teaches them about the power of weather and the importance of preparedness. By blending fiction with factual information, Mary Pope Osborne has created a book that entertains and educates young readers..
Reviews for "An Adventure through Twister on Tuesday in Magic Treehouse"
1. Matthew - 2 stars
I found "Magic Treehouse Twister on Tuesday" to be quite disappointing. The plot lacked depth and the characters were one-dimensional. The writing felt rushed and lacked the magic that I have come to expect from this series. Additionally, I found the topic of tornadoes to be dull and uninteresting. Overall, I was not impressed with this installment of the Magic Treehouse series.
2. Emily - 3 stars
While "Magic Treehouse Twister on Tuesday" wasn't the worst book I've read, it definitely fell short of my expectations. The storyline was predictable and the pacing felt off, with some parts dragging on while others were rushed through. I also felt that the book didn't do justice to the topic of tornadoes, as it only scratched the surface without truly delving into the science or the impact they have on communities. Overall, I would say this book was just okay, and I wouldn't necessarily recommend it to others.
3. Sarah - 2 stars
I was quite disappointed with "Magic Treehouse Twister on Tuesday". The writing was simplistic and lacked the complexity that I have come to appreciate from this series. The characters felt flat and lacked depth, making it difficult for me to connect with them. Additionally, the book seemed to gloss over the topic of tornadoes, with very little attention given to the science or the effects they have on people's lives. I expected more from this book and was ultimately left unsatisfied.
4. David - 1 star
I really did not enjoy "Magic Treehouse Twister on Tuesday". The story felt disjointed and the plot was not engaging. I found the characters to be unlikable and the dialogue to be poorly written. The pacing was also off, with some parts dragging on for too long and others feeling rushed. Overall, I found this book to be a waste of time and would not recommend it to others.