Space Oddity (Part II)

"Houston, we have a problem."

Apollo 13

Is there gravity in space?

Usual answer. No.

Correct answer. Yes.

Students tend to believe there's no gravity in space because they've heard of a phenomenon called 'weightlessness' where astronauts tend to float about in space shuttles. This makes them believe there is an absence of gravity in space. I've seen science textbooks show confusing pictures of this also.

This can be explained by answering the second question in my previous post.

When the space shuttle launches, what path does it take?

Usual answer. Straight up.

Correct answer. Down.

Down? How can it go into space by going down? Maybe that's what you're thinking right now. But, imagine that you take a ball and throw it. It may go 20-30 metres. The reason it doesn't go further is almost purely because of gravity. Gravity brings the ball down to hit the ground, and it won't go much further after that. Imagine now, that you threw the ball a bit harder. It would go that bit further before hitting the ground. Gravity always makes it fall at the same rate, so throwing it harder will get it a bit further before the inevitable happens. 

Imagine you throw a ball a third time. This time though you throw it incredibly quickly, like five miles per second. If you threw it that fast, it would go so far that by the time it came down again, the Earth wouldn't be there for it to fall onto. That is because the Earth is round, and it would curve away at the vital time. You would have thrown the ball over the horizon, which from your point of view, is DOWN.

Incredibly technically complicated schematic of a space launch

This may disagree with your belief of watching a shuttle launch, such as the image in my previous post. However, look at this...

What goes up, must come down

Thrown over the horizon

 Actually the shuttle is like a ball which has been thrown incredibly quickly and falls off the edge of the Earth over the horizon. It falls over, and then falls forever. No more rocket fuel is required. It will continue to fall toward the Earth and always miss. It's a kind of perpetual motion. All satellites in space orbiting the Earth are all falling towards us in this way, but they all miss. So is the Moon. We're doing the same with the Sun. And the Sun and the Solar system is doing the same with the centre of our galaxy.

In fact, the worst thing a shuttle could do would be to launch vertically, as it would exhaust its fuel, start to decelerate, then come to a stop. It would then fall towards the Earth pretty much straight back down the way it came (a bit like Wily Coyote when he realises he's stepped over a cliff) and burn up in the atmosphere.

So why, if all of those things are under the influence of gravity, and there definitely is gravity in space, does it appear that astronauts are weightless?

Because it is due to their point of view. They are effectively in a lift, that is falling towards the Earth. As everything that falls in gravity falls at the same rate, they too are falling at the same rate as the 'lift'.

So, as the lift is falling, there is nothing to push back on their feet where they are standing. Relatively to them though, everything is still, and they are able to 'float'. In fact, if you were stood still by the shuttle, it would rush past you at around 17,500 mph as it falls towards Earth. To them, they are falling at the same rate as the shuttle so they are able to move around. It's a like a very long skydive without any air resistance in a lift that is doing the same thing at the same time.

It is actually BECAUSE of gravity that they are weightless! 

These facts are always interesting to me.  Yet it is very rare I come across a student who realises them.  It seems a shame that something so amazing and beautiful isn't explained to students in school - or that they can get a GCSE in physics without knowing any, er, physics.  

Space Oddity (Part I)

“And all the science, I don’t understand,

It’s just my job 5 days a week.”                                         

Elton John, Rocket Man

While I’m tutoring my students, I tend to unnerve them by suddenly asking:

• Is there gravity in space?

Going up?

 And

• When the space shuttle takes off, what path does it take?* 

Invariably, I get the wrong answers to these questions.  Especially if the student has a GCSE in physics.  Then it’s almost certain they’ll get it wrong.

So why is this?

How do I know they’re going to get these wrong?

Because they are questions that they are never asked.

Students are asked questions where they already have been given the answer in some previous lesson.  Then it’s just a question of whether they remember the answer.  Questions that are different from this in any way completely throw them.

This is because children are not educated, but fed information.  This is taken to be the same thing. 

Another example I saw in a school science textbook was, “Insulin converts glucose into glycogen.”  Test question – “What does insulin convert glucose into?”.  This doesn’t teach what glucose or glycogen are or why this is important, what they do or anything!  It just appears from outside that something is happening, something is being taught, when in fact absolutely nothing is going on. 

Richard Feynman, one of the most highly regarded theoretical physicists of the 20^th century and a Nobel prize winner, used to loathe this kind of education and first became aware of it in Brazil while on a visit there.  He noticed the students all passed the exams, but when they were asked a question that wasn’t the same as the exam, they had no idea of the answer or worse, how to figure it out.  He stated that ‘No physics is being taught in Brazil!’ even though there were many schools and universities churning out ‘physicists’ and almost caused a diplomatic incident.

Thinking differently

It was a theme he found himself returning to in America where he was asked to evaluate high school textbooks.  He found the same thing.  Even the vetting process for the choice of textbooks followed this ‘Emperor’s New Clothes’ phenomenon as committee members voted on a book without reading it – which drove him mad. 

However, he was right.  This is what is happening in schools and textbooks in the UK.  Maths and science are taught in this way.  That is why children aren’t able to do these subjects, achieve nationally low pass rates and worse, lose interest in them.  They are not taught why things are, but how to pass an exam on it.

There can be nothing more dull then learning to pass an exam, the details of which mean nothing to you.  And when you ask why things are and show some curiosity, you are shouted down and told the immortal words, ‘It Just Is’.  I once discussed with a maths teacher why a minus times a minus is a plus – because she was complaining that her students were asking her why it was! – and I eventually got her to admit that she didn’t know why.  Of course, IT JUST IS.

So what’s the solution? 

My idea is to use what the students already know.  Use their intuition to teach them concepts.  Then when it has been confirmed they actually do understand the three rules of maths, use inductive learning to figure out all the techniques required to be able to manipulate numbers, algebra, trigonometry and calculus.  Because when you take this approach, it can be seen to be all the same.

Tutoring, this only takes a few days of one-to-one tuition.  I bet it would be more efficient to tutor each child individually for 3 days then to teach them nothing for 10 years.

I’ve had students in year 10 who when they first come to me, can’t multiply two numbers like 23 x 41.  If that’s the result of 10 years of class education, something isn’t working.  Even if they can multiply numbers together, they do it in a horrendously complicated way, either by the misnamed ‘Grid Method’ or by ‘Long’ Multiplication which is almost as bad.  But worse than that, try asking what multiplication is for.  What do we use it for?  They have no idea.  They’ve not been asked that one.  They can just do it.  Maybe.

They’re also not shown how to know if their answer is correct.  They have to ask the teacher ‘Is this right?’.  Instead, they should be able to check easily and quickly whether it is correct.  Why?  So they become independent learners, who use logical thinking skills to solve problems.  That is one of the main reasons to learn maths and science – apart from its applications. 

We could have a world where these subjects are exciting, interesting and spark creativity and new thinking.  Where a child asks…”Well, if that’s true, what about this situation?” and they come up with something new!  It’s time we think different.

I hope this is going to change in schools.

I would hope the students become inspired and energised.

But I think it’s gonna be a long, long time…

*these questions to be answered in Part II...see you then.