Help yourself to reduce loss of learning time

Here is a golden opportunity for all learners and teachers! We are so proud to have Dr Angela Stott as part of our teaching force here in the Free State. Apart from doing research on critical matters in Physical Science education, she is an excellent teacher with a wonderful reservoir of resources.

She extends the following invitation to learners and teachers, which you should not miss:

"Hello! To help reduce loss of learning time, I've made a lot of my Science resources available for free. Please help me to make people aware of these resources by sharing this message to teachers, parents, grandparents and learners (Grade 8&9 NS and Grade 10-12 PS).

While school opening has been delayed, why not get your learners / kids / yourself started on the curriculum at home?... To help you...

Check out my renamed and overhauled website: www.learnscience.co.za

Note two new features, as mentioned in this promo:

• Movies on every CAPS topic for Gr 8&9 NS and Gr 10-12 PS
• Quiz competitions per grade. First set of competitions' deadline is 28 Feb.

Teachers, perhaps you could set your learners the task of completing the quiz competition - which would also require them to study the topic, e.g. by watching the associated movies - while we wait for the new term to start?

Learners, why not participate in these quiz competitions to get a head-start while you wait for schools to open?

Best wishes!
Angela Stott (Dr)"
LearnScience.Co.Za
https://youtu.be/C6zNxB-ChA0

How far have the manholes travelled by now?

Recently I saw a post on the Facebook group RSG Sterre en Planete by Jan Viljoen. He shared a post of Keith Anderson about the fastest manmade object that was not a hypersonic jet or spacecraft, but a large manhole cover. What an interesting story!

©Reuters: A cameraman films an atomic mushroom
cloud during Operation Plumbbob; 19 July 1957

Keith Anderson wrote further: "When the US started doing underground nuclear testing, nobody really knew what would happen. One test bomb was placed at the bottom of a 485-foot deep shaft on July 26, 1957, and someone thought it was a good idea to put a half-ton iron manhole cover on top to contain the explosion. The bomb turned the shaft into the world's largest Roman candle, and the manhole cover was nowhere to be found. Robert Brownlee, an astrophysicist who designed the test, wanted to repeat the experiment with high-speed cameras so he could figure out what happened to the cover. So, another experiment was created, this time 500-feet deep, and a similar half-ton manhole cover was placed on top. On August 27, 1957, they detonated the bomb. The high-speed cameras barely caught a view of the cover as it left the top of the shaft and headed into oblivion. Brownlee used the frames to calculate the speed to be more than 125,000 miles per hour; more than five times the escape velocity of the earth, and the fastest man-made object in history."

Physicists have debated the whereabouts of the two manhole covers ever since. Recently, with the help of supercomputers and a lot more scientific knowledge, physicists are certain that they wouldn't have had time to burn up completely before exiting the atmosphere. This means both of the remaining pieces would have passed Pluto's orbit sometime around 1961 and are way beyond the edge of the solar system by now.

You can read two further articles, with beautiful pictures, from MailOnline and BusinessInsider about these amazing phenomena. I have made pdf files of the articles. Click here for article one, and here for article two.

For those who want to know more. The escape speed for Earth is 11,3 kilometre per second. At that speed, one can cover the straight distance between Pretoria and Cape Town (if we take it at 1 315 km) in 116 seconds, or about two minutes. Makes one think about this amazing universe and the achievements of science!

How hard was it to get the Saturn V rocket, 111 m tall and weighing 2,8 million kilograms (click here for more info) to move at 11,3 kilometre per second to take the Apollo 11 crew to the moon in 1969? Nevertheless, Werner von Braun and his team had done it during the Apollo missions! You may want to click the label "von Braun" below this post to read more about Werner von Braun.

The SS Warrimoo: The ship that simultaneously spanned four different hemispheres and two centuries

Here at the beginning of 2021, it is worth the while to take notice of the amazing story of the SS Warrimoo.

Image: https://www.snopes.com

On 31 December 1899, it crossed the equator and the international date line. This sparked a few amazing facts! Read the original article here or download a pdf version here. 

The world is such an interesting place!