Science Experiment: Indicators

In this experiment we made an indicator, by chopping red cabbage and leaving it in hot water for 30 minutes. Then we put the mixture through a sieve to take out the cabbage. The liquid was dark purple.

We poured a small amount of the indicator into small glasses.
The substance we were going to test were lime juice, vinegar, tonic water and shampoo, but the shampoo stayed purple.We also tried bleach and stain remover.

The lime juice, the tonic water and the vinegar changed the indicator to red, this means that they were acidic.
The bleach started purple but then after a few stirs it went blue, orange and then yellow! That was weird!

When we tested the stain remover it went completely blue, which indicates that it was alkaline.

It was interesting to see that different liquids can be acidic or alkaline, and that they change the indicator different colours.

Science Experiment:Tangling your Tastebuds

In this experiment we made drinks from soda water, different flavours, and different food colourings.  We made drinks with different flavours, but used colours that we thought didn't look anything like the flavour.  The point of the experiment is to show how colouring affects how we taste.

The flavours and colours we used were:

• pink almond
• green worcestershire sauce
• blue peppermint
• purple vanilla

You can see the result here:

Next, we labelled each of the drinks with a number, and hid their actual flavours.  Then I asked each member of family to try the drinks and tell me what flavour they were.  My brother Tyler, doesn't no flavours, so we let him pick from the bottles of flavours (but we didn't put out the bottle of Worcestershire sauce, because he wouldn't have tried any of the flavours if he knew one of them would be that!)  Here's a picture of what my family saw:

We also added sweetner to the drinks to make them taste better, because the flavours we added smelled nice, but didn't taste nice.  I even got to have a go at the experiment, because my dad mixed up the glasses so I couldn't remember the flavours.

Everybody in my family guessed peppermint, because the smell was so strong -- it didn't matter what colour it was (Tyler said it was chewing gum -- which is close enough, since we have lots of mint gum!).  My mom and I got mixed up with the purple vanilla, and nobody guessed the worcestershire sauce.  But the worcestershire suace drink tasted really really awful.  In fact, it was so awful, words can't describe it -- only this picture of Tyler trying the green worcestshiresuace drink comes close:

It was fun tasting weird stuff, and trying to trick my family!

Science Experiment: Bottled Tornado

I've seen this before, at the Thinktank and at a science day at the Erasmus Darwin house, but I never stopped to think about why it works until now.  What's supposed to happen, is that we make a tornado inside  a bottle.  We do this by getting two bottles, and making half centimeter holes in each of the bottlecaps.  We then glued the bottle caps together (we had to use really strong glue and let it dry for a long time).  Then we filled one bottle with water, and we put in some pink food colouring and glitter so we could see the currents in the water.  We screwed both bottles into the glued double bottlecap, to make this (except not sideways):

If you spin the top bottle carefully enough and hard enough, the water will start spinning around, and it will move along the sides of the bottle.  After we stop spinning, the water keeps moving -- this is called centripetal force.  I've heard of centrifugal force, which my dad says is the opposite of centripetal force, but I'm still confused.  He said centripetal force keeps "tripping" you in a circle, where centrifugal (with an "f" in it) force makes you "fly" off.  I don't think that helps.

Anyway, as the water goes along the side of the bottle, some of it slips through the outside of the hole in the bottlecap.  But this only happens if the water is spinning -- if it's not moving, the water doesn't go through the hole.  I learned that the empty bottle on the bottom is not actually empty, but full of air.  And if water is to go in to the bottom bottle, air must somehow escape from it, because the air is stopping the water from coming through.

When the water is spinning along the sides, air can come up through the middle -- and that's what a tornado does (except that's cold air failing with hot air).  So the tornado lets water go into the bottle bottle at the same time that air goes into the top!

Tornadoes are deadly.

Science Experiment: Splitting Light

In this experiment, we actually split white light (which is made of all colours) into a rainbow (the different colours that make up white light).  We did this by making a slit in a piece of cardboard, that was just big enough to let a bit of light through.  Because the slit was so small, each colour of light could only fit through at different angles.  We use a glass jar filled with water to act as a lens, putting the card with the slit on one side of the jar:

When we shined the light through the slit, the water carried the light and refracted it out at the different angles.  On the other side of the jar, if we held the light at just the right angle, there was a spot made up of a rainbow with all the colours split apart.  This is one of the best colour spots:

I learned that black is not one of the colours that makes up white light, because black is actually just darkness (no light at all).

Science Experiment: Why is the Sky Blue

In this experiment, I was supposed to learn about why the sky looks blue.  Light is made up of all the colours (except black, which is just no light), and sometimes when light is shining on something, only some of the colours get through to the other side.

To test this, we put some milk (just a little) in a jar full of water.  Then we shined a flashlight into the jar in a dark room.  When the light shone down on the top of the jar, the milky water on the top looked blue, like the sky.  When we shined the light through the side of the jar, the light coming out the other side looked red.

Here's the flashlight, jar and milky water we used:

The different colours are supposed to be because the particles of milk block the light so that short-wave light gets caught and bounced around (at the top of the sky), while long-wave light makes it through the other side (sky at sunset or sunrise).  I'm not sure it makes sense, because milk, the air in the atmosphere, and light aren't things that I think of as interacting.  My dad says the blue colour is actually just mostly light reflected from ozone molecules in the atmosphere -- that they are blue, just like my blue school bag.

My dad gave me a different example of only certain light passing through, and I thought this was much better:

Blood and flesh only lets through red light, like a sunset!

Science Experiment: Periscopes

In this experiment I made a periscope out of a card board template and two pieces of a mirror.  Well, actually...my dad put it together, because it was too hard for me to make the small cuts and glue the tiny tabs.  Here's what we started with:

   
Here's the finished periscope (the mirror in the open end doesn't show because the other mirror opening is closed to the rug, and no light is coming in):

I learned that perioscopes can be used to see over obstacles and corners.  This works because light reflects out from each mirror at the same angle in comes in at.  This was sort of fun, because I got to try and find things around obstacles using the periscope.

Science Experiment: Chromatography

In this experiment, we found out that the colours in some things (like marker ink and smarties) are actually made up of different colours.  We used filter paper to disperse the colours in a black crayola marker and some different colour smarties.  Because the chemicals used to make each colour have different properties, they get "soaked up" in filter paper at different speeds.  This means we see some of the different colours race out in front of other colours.  We used water to speed up the absorption of the colours in the filter paper.

Here's what happened when I drew a small black dot on some filter paper, and then added a bit of water:

The most obvious colour coming from the black is blue, but there's definitely bits of green and even some pink we think.

I then tried putting some different coloured smarties on the filter paper, and adding some water.  We waited a long time, but not very much unexpected happened:

I think some yellow came from the green smartie, and some green came from the brown smartie, and come purple came from the red one?  It was hard too tell, and took a while.

Next we wrote my name on the filter paper using the same black crayola marker as above -- I wrote it once, and my dad wrote it once, then we added water:

You can see lots of blue here, some green and pink again too.

For the last experiment, we cut a strip from the middle of the filter paper, and bent it down into a cup of water.  I drew another black dot in the middle of the filter paper at the base of the strip.  The water, although slowly, eventually wicked its way up the paper and to the dot.  This was very interesting because even though it was the same marker and the same water, we definitely saw different colours this time:

Most noticeable this time is the orangey-brown colour.  But there is also a turquoise wisp, along with the blue we saw before.  The pattern it made this time, just from a small dot, is very interesting.

I had fun doing this, mostly due to my discovery that smarties taste very good when they are wet.  I also learned that the colours in some things are actually made up of different colours put together.

Science Experiment: Steady Hand Game

In this experiment we made a working steady hand game.  A steady hand game requires you to move a hook along the length of a wire, without the hook actually touching the wire.  If it does touch, the game will make a noise or show a light, and that means you've lost the game.

We used electrical components to make a circuit.  I learned that electricity needs to flow (like water) in order to work, which means it needs a way in and out of each component.  I also learned from this that when the electrical components are all connected properly, the circuit is closed, and when you disconnect something the circuit is open.

These are all the pieces before we started:

After following the instructions we had made a working steady hand game with a buzzer!

The next picture shows the buzzer and light connected in series.  Only the buzzer worked, as the buzzer made too much resistance for the light to work too.  We then connected the light and the buzzer in parallel, and they both worked at the same time!

I learned a lot from this, but I really just wanted to play the game!