Unknown (age 7) asked – “Why is the sky blue?”

Hello unknown. I would not normally answer questions to an unknown questioner, but, as it it such an interesting question I asked my friends for some comments.

You are right. Where does the colour come from? It was in 1671 that the famous scientist, Newton, discovered that white light was a mixture of different coloured lights. He did this by passing white light (the light from the Sun) through a glass prism. Look at what he got……….

Later it was found that some of the blue light in the Sun’s light had difficulty passing through the Earth’s atmosphere. this blue light was scattered as it passed through the atmosphere therefore giving the sky a blue colour.

Some of the blue light still got through and appears as part of the white light in the prism experiment and also in the rainbow. In the rainbow the drops of rainwater act as small prisms.

Hope this makes sense. if you want to give your name please let me know in the comment box.

(amended 21/9/18 – raindrops as prisms added)

Jaydeep (7) asks “Why do sponges absorb more hot water than cold water?”

Jaydeep. An interesting question, which I need to think about. I suspect it might be a question of ‘testing’. How did you arrive at the question? Did it include elements of ‘fair testing’? I shall start by passing it over to my friends.

Thanks team. Yes, I agree, science knowledge is based upon fair testing. Jaydeep’s question suggest that he has evidence that sponges absorb more hot water than cold. It is and interesting thought BUT is it true? That’s what a scientist would ask.

What do I think? My initial thought is that as water gets hot it expands, so…., the sponge might absorb less water. From another viewpoint it might be argued that the hot water ‘warms up’ the sponge and causes the sponge to expand, thus absorbing more water. Another argument might be that because both the water and the sponge expand when they get hot …..things cancel out.

The important point is that if the original investigation was not fair all the arguments about Why are meaningless.

Jaydeep ….do a fair test`and then ask the question. Many thanks for an interesting input.

“Why do spiders make webs and what are they made of?” asks Emily (7)

 

Thanks Team and thank you Emily. My first thoughts are about catching a spider and trying to keep it at home or somewhere else or finding a spider in the wild so that you can see it making, or looking after its web. I am however reluctant to suggest both catching a spider or keeping it in an indoors.

In some countries spiders can be dangerous so please do not interfere with it until an adult has identified it and  said that it is OK to collect it, or observe it closely.  If, with an adults permission, you can keep a spider then a large plastic aquarium would probably provide a good home for it.

A spider’s web is made of a type of silk, so ask an adult if they could find some silk for you to investigate. Maybe you could use it to make a web and see how strong it is?

If you do keep a spider, at home, or in the classroom you will have to decide how you will feed it. That will be an interesting investigation.

Look at this video of a garden spider building its web. In the first part of the video everything is slowed down. In the second part of the video things are at the real speed of web building.

Mason (7) asks “Why is water wet?”

Thanks team. Let us start with a investigation. Let us look at the way water interacts with different materials.

 

Let us now look at the properties of water drops. Firstly let me define ‘cohesion’ and ‘adhesion’. The term ‘hesion’ means  … to stick. Cohesion is is the attraction and sticking together of the same things while adhesion is the attraction and sticking together of different things.

Look at the image of the water drop below. Each water particle is attracted to the other water particles around it , this is cohesion. Now add a different surface and the water particles are attracted to that rather than each other, this is adhesion. When adhesion occurs we get the spreading of the water drop and wetting,  providing the adhesive forces are greater than the cohesive forces.

So what about your investigation? Is there any evidence of cohesion or adhesion?

Here is a thought. it has been suggested that water is ‘wet’ because you can feel it’s wetness.

Maybe another little experiment.

You could let me know by clicking on the ‘Reply’ box below.

Some questions on Gold from Chantelle (7), Shelby(9) and Mary(9)

Chantelle asked “Why is gold so hard to find?”

Shelby asked “Why is gold so heavy and hard to pick up ?”

Mary asked “Why is gold so expensive?”

Chantelle, Shelby and Mary some great questions , thank you. But are they science questions? Lets look at what a science question is.

science question is a question that may lead to an idea and help us in answering (or figuring out) the reason for some observation.

For example ‘Why is gold so heavy?” …so firstly let us look at what gold is. Gold is a solid –  Is it a rock? Is it wood? Is it plastic? Is it a metal? ……it seems to fit into the group called metals (it’s cold to the touch, it’s solid, it can be scratched, it’s shiny, it’s heavy) it’s a metal. So Shelby’s second question is a good science question.

Is it heavier than other metals?  It doesn’t seem to be heavier than other metals but how do I test this?  Fair tests are important in science investigations. Being fair I compared my gold with with metals of comparable size? It is heavier, why? Maybe the bits which make up the gold are heavier than the bits that make up other metals?

Chantelle. I think gold is quite easy to find compared to other metals. Lots of other metals, iron, silver, copper and aluminium exist as minerals  so they are quite difficult to find. What is a mineral? Look at the following page.

Science Master

 

Liam (7) asks “What causes an earthquake?”

Thanks team. When the Earth cooled down the crust was formed over the whole planet.

However, after the crust was formed there was still a lot of activity in the molten core of the Earth. This caused cracks in the crust and it is these cracks which are the cause of Earthquakes. Scientists have investigated the cracks and created a map of where they are.

You can see these in the maps below.

The lines indicate the cracks on either side of our Earth. The spaces within these cracks are called  ‘plates’. These plates are constantly moving (very, very very slowly).

Any idea what is making them move?

Some plates are moving away from the plates next to them BUT that means they are also pushing up to other plates on the surface. It is this movement that causes the earthquake.

Where do you think the earthquake happens …is it in the middle or outside of a plate? Where is your country?

I have created two jigsaws of the Earth images above. Print them, stick them on some cardboard, and cut them out and make your own world of ‘plates’ and try moving them.

Link to Jigsaw 2

Link to Jigsaw 1

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

Mariah (7) asks “Why are pushes and pulls forces?”

Thanks team and thanks Mariah for the question.  My team are quite correct there are lots of pushes and pulls. Can you think of more? What about gravity? That pulls things to the ground. What about the wind, that pushes things.

In science and in our daily life we put things into groups. The things in the group all have something in common. All fish are grouped together, they can all breathe underwater. Can you see anything else they have in all fish have which is the same?
All bicycles are grouped together, they all have two wheels. They also have some other things in common (the same).

If all forces are grouped together , they all involve pushes and pulls. The group that pushes and pulls is called forces.

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

“How are sounds made?” asks Mohammed (7)

Thank you team. Some of the things in the image above make sounds without tapping or blowing. Can you find them? Miwah asked a similiar question where he investigated how the sound a drum made was created. Can you try an make a sound using a ruler. Try holding one end of it on the desk and then bending it slightly by pushing down on the end which is not resting on the desk.

Now let go ….. and here come the questions.  Did you hear anything? What did the end of the ruler do? If there was a sound when did it stop?

Another question. If there was a sound what part of your body detected it? So how did the sound get to you? What is between your bodies sound detection and the ruler?

Now for a little bit of information. How did the ruler move when you let go of it? The word to describe this movement is ‘vibration’. A vibration is a continuous small movement up and down, or side to side. This is what Miwah discovered in the drum investigation. Below is a small video of a plastic ruler being pushed downwards and then allowed to vibrate.

Investigate making other objects making sounds and see if you can ‘feel’ the vibrations.

Any more thoughts , then please make a comment or ask another question.

Ava (7) asks “Why do mirrors change words ?”


Ava, can you see how the image of the dog in the mirror is different from the dog. Look at the dogs raised ear. What side of the head is it on? NOW imagine you are the dog in the mirror, what side of the head is the raised ear on.

Try this, look in a mirror and point your right finger at the mirror. Now try to put yourself in the position of you in the mirror and what side of you is your finger. Is it your right finger or left finger, in the mirror???  Wow. The mirror has inverted your image (the dictionary says inverted means  – put upside down or in the opposite position.)

Now try a mirror with some words. Try it with this word  Mirror Me. Write it on a piece of card or paper and look at it in a mirror. What does it look like …..is it like this?

Think about what you are seeing. Why can you see the image in the mirror? Think about reflection? This is a very difficult area of understanding BUT you can have a lot of fun with it.

Updated 12/6/17