“Is time travel possible ?” asks Lachie (9)

Thanks for the question Lachie . My friend is correct, Albert Einstein thought that time travel would be possible because of something he called relativity. It seems to be about the time it takes to move through a given distance (space) and the speed of light. The faster you go the slower the time that has past. That is a very, very difficult idea to understand. Even I find it difficult ….. but lets try and give you an example

Suppose you could move through space at or around or about 186,000 miles per second, which is the speed at which light travels?

Say you were 9 years old when you left Earth in a spacecraft traveling at about the speed of light (which is much faster than we can achieve now), and celebrated only five birthdays during your space voyage. When you get home at the age of 14, you would find that all your classmates were 59 years old, retired, and enjoying their grandchildren! Because time passed more slowly for you, you will have experienced only five years of life, while your classmates will have experienced a full 50 years.

So, if your journey began today in 2018, it would have taken you only 5 years to travel to the year 2068, whereas it would have taken all of your friends 50 years. In a sense, this means you have been time traveling.

According to Einstein’s ideas you can only move forward in time you cannot move backwards. However we do not at the present time have any vehicle that could reach the speed of light so if you want to travel in time you might have to wait a little while.
(revised 23rd May 2018)

Liam Astra asks “Why does Mentos lollies make coke spurt everywhere?”

Liam, thanks for the question. Are you sure that you wanted to talk about Mentos lollies? I couldn’t find any mention of them …..only sweets …so I have focussed on them. 

Let me start my answer by showing you my favourite clip of the Mentos/Diet Coke reaction.

My first question is ….is there anything special about diet coke and the Mint Mentos tablet?

Firstly there is evidence (somebody has done some experiments) that diet coke contains more carbon dioxide gas than ordinary coke. When they make coke they add carbon dioxide gas to it. Lots of gases are absorbed by liquids. Oxygen gas is absorbed by water…..this allows fish to breathe. The manufacturers add carbon dioxide to the coke because it enhances (makes better) the taste of the coke. Carbon dioxide, like oxygen is a safe gas  – it is the gas that you and I breathe out – it is created by our bodies.

Experiment 1.  Add a Mentos to a bottle of Coke and one to a bottle of Diet Coke….is the reaction the same? Make sure that it is a fair experiment (talk with others about how you can make it fair). Make sure that it is a safe (if you have them wear goggles) and a tidy experiment. (think about your parents or teachers)

Experiment 2. Now let’s look at the Mentos tablet. Is the tablet smooth or rough to the touch? Try and find something (maybe an adult can find you a little bit of sandpaper) that will change the surface of one of the Mentos tablets (more rough or more smooth) and drop it into a diet coke bottle. What happens? Do the rough and smooth tablets both give exactly the same ‘spurt’?

You could also carry out this experiment with Fruit and Mint Mentos tablets?

Here are some magnified photographs of the surface of a Mentos tablet.

 

So what have we found out? What has roughness to do with surface area? Why does the dissolved gas decide to come out of solution when it meets the tablet?

Let me know your thoughts in the box below.

Some more questions about the Solar System and Space by Seb, Luke, Luca, Sammy and Bowen

Many thanks for your questions. I told the last group that, 3 days ago I visited the Kennedy Space Centre in Orlando. It was brilliant. I was particularly interested in their idea to visit Mars in the near future. However let us look at the other superb questions and see how many other questions they create….that is what science is about.

Seb asked  “What does Mercury orbit?”

Seb, many thanks for the question. Not long ago, in our history, everybody thought that the Sun orbited the Earth. Why shouldn’t they? You see the Sun rise everyday and move across the sky and then disappears on the opposite horizon. It moves, we don’t.

Or could it be the other way – the Earth moves and the Sun stays in the same place? This was a question that a early scientist Copernicus (1473-1543) thought about and and then Galileo Galilei (1564-1642) confirmed ..it was the Earth that orbited the Sun. With this knowledge other scientists (we call them astronomers) worked out what Mercury orbited. What do you think?

Luke asked  “Do Saturn,Neptune or Venus orbit any planets other than the sun/orbit each other?”

A question I think that is linked to Seb’s. What evidence would you think would show that a planet orbited another planet? Think about the Moon, what does that orbit? Does it orbit the Sun? Supposing it did, what would you observe?  It was Galilei who built a telescope that would enable observations of the planets and therefore provide evidence which would answer the question. Like all science once the hypothesis has been made it can only become an accepted fact after relevant observation and production of evidence.

Luca asked “What is the furthest distance of a spaceship travel?” and “What is space made of?”

Luca, two great questions. For the first question I must admit I have no idea. From my visit to the Space Centre I know that NASA is planning to go to Mars. I see no reason why humankind will not be able, in the future, to leave the Solar System. We can already send satellites and other objects beyond the Solar System.

To your second question, the easy answer is ‘nothing’, other than stars, planets, asteroids, satellites and other bits an pieces. It does however contain what would be called ‘radiation’ of different types, otherwise we would not be able to see stars, the Moon or the Sun. Do you think it could contain anything else?

Interestingly, in Earth orbit, you would not be able to see any stars in space? Any ideas why?

Sammy asked “Can a black hole swallow Earth? If so when could this happen?”

Sammy, what do you think a black hole is? Why do you think it is called a black hole? I think it is something to do with that magical force called gravity. Think about gravity.  What does the gravitational force that an object has, depend upon?  Think about the force that pulls you to the ground. Think about the force that keeps the Earth in orbit around the Sun. Think about the force that holds the Moon in orbit. A black hole is a hole which light has been pulled into it, by a gravitational force. Think about a gravitational force that can pull light into it …….will it be able to swallow the Earth?

Sammy …something I didn’t know. It is thought that all galaxies have a black hole. Even our Milky Way galaxy has its own black hole.

A NASA photograph of a black hole. There is one…its a dot in the middle of the bright circle in the middle of the picture.

Bowen asked “Why do humans still think that there are resources on the moon? I think there are none.

A interesting question Bowen which I would like to challenge. Why do you think there are none? My thinking is that the Moon seems to be made of rocks and rocks are sources of all sorts of things. A lot of rocks contain silicon, what do we use silicon for? A lot of rocks (moon rocks included) contain aluminum which is used in a variety of ways, the rocks also contain hidden oxygen, a lot of rocks exist in the form of oxides (iron oxide is an example). Probably the biggest resource that the Moon has  is a low gravity. Any ideas why that is so important? Let me know.

“How does sound travel in things other than air?” asks Lilly(12)

Hello Molly, Science Master here. Lets’ check that we understand how sound is produced and what it is. Sound is a form of Energy ( see Science Master Special).  It is transmitted by particles hitting each other.

So what do you think? Could you hear the sound underwater?  Could you hear the sound further along the metal tube?

Lets improve the experiment by making it fairer. How could we do this?

Let us look at the particle arrangement in the air, water and metal.

The average distance between particles for a gas is 4 nanometers (1 nanometer = 10-9 meters), for a liquid it is 0.2 of a nanometer and for the solid 0.0002 of a nanometer.

So. If the first line of particles in the gas starts moving it has to travel 4 nanometers before it hits the second row. For the liquid this would be a smaller distance and for the metal it would be hardly any distance. What does that tell you about the speed of travel of sound?

Does your experiments support your thoughts? Maybe it needs to be modified? How could you modify it to really test your thoughts.

Just a thought of my own. The sound source (drum, spoon tapping, violin) gives the particles around it ENERGY. Those particles in air have to travel a long distance before they hit another particle and pass the sound on. All this time they are losing ENERGY. For the metal the particles only have to travel a little way before passing on the vibration.

(added 27/10/16)

Not sure of something Lilly…ask another question.

(Anyone reading this post who wants to ask a question or make a comment please feel free to do so)

Ujala asked questions about where Science came from.

Many thanks for the question Ujala. I hope my friends answers satisfy your curiosity. Interestingly although ‘Natural Philosophy’ and ‘Science’ were names that evolved 2500 years ago there is evidence that ancient civilizations practiced ‘science’ more than 4000 years ago in Africa where they used measurements to create maps of plots of land by the Nile – Geometry is a scientific tool.

Any reader can ask another question or leave a Comment in the Leave a Reply box below

“If a cow ate only strawberries would it’s milk taste like strawberries? was Reginalds (grade 2) question

It is amazing that a cow has four stomachs like sheep and goats. The four stomachs facilitate the process of breaking down the grass into an edible, consumable, foodstuff.  Reginald, I am sorry that I cannot suggest an experiment to test your interesting thought. Most of the strawberry you eat is organic fibre and cellulose in nature. The sugars and flavouring are quite volatile so I would imagine (don’t know) that they would not survive the four stomach processing. I am happy for you to come up with some additional information.

Ash asks “Why do we need academic learning, what is it’s purpose?’

Ash. This is a question I will try to answer without the help of my friends. It was a challenging question. This is a personal view.

I have tried to attempt academic learning for most of my life. Notice the word tried. Academic learning for me is learning things that would help me solve scientific questions. I learnt about materials and then about atoms and molecules and their properties and then about ideas on how this dictated the way in which they behaved. I then used this to help with my own ideas.

There are however lots of different forms of academic learning in all subject areas. Think of the people who are interested in history. Their learning could involve studying and interpreting lots of old and ancient texts – or modern ones. Does history help us in understanding what is happening in the world today?

Think of the engineer who would like to improve the jet engine. Look at the learning that she/he would have to do to help them solve the problems that jet engines might have.

Don’t however, in your life, avoid the other types of learning. Learning by listening, learning visually, and learning through actions are just as important.

Now and again academic learning involves tests, class test, school tests, national examination tests. They are horrible but on the other hand they help you in the steps of the academic learning that you go through.

“How do western toilets work?” was Vinay’s (10) question,

Vinay. These are the initial thoughts of my friends. I will reply later.siphon

I’m back ….. So the siphon it is. For animations on siphons go to this great animation   where you will see a true siphon in action.

The amazing thing is that initially the siphon was thought to be delivered by air pressure. Then somebody created a siphon in a vacuum. So ideas have changed. Not everything in science is ‘absolute truth’ . One of the driving forces in science development is attempting to disprove accepted laws.

Why did you want to create a blog? was Tyler’s question.

Tyler

On my opening page I talk about the importance of asking questions in science. We find out about the world around us by asking questions and then trying to find answers to those questions.

We might sometimes think our question is stupid and people will laugh about it. Sometimes asking questions in a classroom seems to be a bit like acting, there you are asking the question with 30 people listening. That can be horrible for some young people and even lots of adults. This can happen…so this blog lets young people ask their science orientated question in a non-threatening way and you can be sure that it will be listened to and somehow answered by me and my team.

I ask you to look at Natalie’s question… what is a chemical? That question is so important in understanding a scientific view of the world. Well done Natalie.

Tyler – thank you for the question

Science Master