Science Sunday:Homemade seismograph

R had to make her own seismograph for her homework this week and it was so cool we thought we would share it here.
To make our seismograph we used:
A strong cardboard box
wire
a plastic cup/yogurt pot
weights to put in the cup (we used marbles)
a pen
sticky tape
paper to record you tremors
Put the box so the front is open.
In the top of the box make a hole for the wire.
Take the cup, make a hole in the bottom for the pen, secure with tape.
Punch holes in the top of the cup so it can be suspended with the wire.
Weight the cup with the marbles or whatever you are using.
Tie the wire to the cup and feed it through the hole in the top of the box.
Arrange the wire so that the pen at the bottom of the cup just touches the bottom of the box and knot the wire so it stays at this height. This is the tricky bit. The pen will draw on the paper as the box moves, if the pen drags on the paper it won't work so well so take some time over this.  Finally put some paper in the bottom of the box under the pen.

There you are, your own seismograph.  The only difference between this and the real thing is that the real thing has a roll of paper that moves at a known speed so you can tell how long tremors last and how far apart they are.

How it works.  The weighted cup at the end of the string acts like a pendulum.  It is free to swing independently of the supporting box; sometimes this is called being "isolated".  Because it has been weighted and is heavy it is difficult to start it swinging, it has a large "inertia".  When the support moves the pendulum tends to stay still and so you get a movement of one relative to the other which is recorded by the pen.

Unless you are very lucky (or unlucky depending on your perspective) it is unlikey that you will be able to test this with a real earthquake so try placing the box on the floor and then jumping up and down, put it on the back of your bike, walk and then run across the room etc.

For more Science activities check out Science Sunday with Ticia over at Adventures in Mommydom

Science Sunday: Hyacinths

One of the problems with teaching children about growing plants is that it takes so long that they have lost interest way before anything appears.  I think this is why you get the ubiquitous cress seeds on cotton wool in every preschool in the world.

This time of year the shops near us are full of bulbs and so we invested in a hyacinth bulb in a hyacinth jar so that we could do something a little different.  In just four days it went from no roots at all to this:

A is in charge of his "little beauty" and checks it about 100 times a day. Now all we need is the flower to appear.

Science Sunday: Bubbling Volcanoes

Not very original I know but R is doing about Earthquakes/Volcanoes etc again and needed a model of a volcano for her homework so we dragged out the old papier mache volcano with the bicarbonate of soda/vinegar larva.
To make the volcano itself we took the side of a large cardboard box as a base.  In the middle of this we stuck an upside down yogurt pot and then another pot on top (this will hold our bicarbonate of soda etc later).
At this point cue the scrunched up newspaper and masking tape to build it up into a volcano shape around the pots.
Next comes the boring messy bit.  Layers of newspaper and glue.  Although there are recipes for making your own flour and paper glue (just use Google you will get hundreds) I prefer to use a watered down PVA glue.  You can buy two litre containers from building merchants where it is sold for sealing bare plaster walls before decorating - the last container I bought was when A was born and he is now 7!  To use add roughly equal amounts of water and glue so that it looks like milk.  This saves a whole lot of faffing about boiling/mixing/cooling and if you need to spend several days making your model (and lets face it it is not the most interesting thing in the world to do all day) it doesn't start to stink!
Once all the paper was dry R painted the model.

To make the bubbling larva.  Put some bicarbonate of soda  (also known as baking soda and has the formula NaHCO3) into the yogurt pot. Carefully pour in vinegar (with a little washing up liquid) that has been tinted with red/orange food colouring.  You should get a bubbly mixture that goes down the side of the volcano.  Of course since R wanted to do this at school we had a trial run first before she had to do it in front of her classmates with an identical sized pot to see how it would go.  Just a note don't use baking powder for this experiment -although it contains bicarbonate of soda as an active ingredient it doesn't work so well as the pure thing.
For those interested in the chemistry part vinegar and bicarbonate of soda is an acid:base reaction.  The bubbles of gas are carbon dioxide.

Science Sunday: Hot and Cold Air

This experiment was one inspired by my daughter R who requested a balloon experiment with the balloons left over from B's party.
First we took one small balloon that was blown up to the size of a baseball.
Experiment 1:We put it in the freezer overnight to see what would happen.
What did we think might happen? (Hypothesis): R has seen things put into liquid nitrogen at school that shatter so her original hypothesis was that it would freeze hard.
What did we see? (Result): The rubber of the balloon remained soft but the balloon got smaller.
Experiment 2: Then we thought of something else. we put it in a sink of hot water
What did we see?(Result): The balloon got bigger
What did we prove? (Conclusion): When the molecules that make up air are cold they're together, when they're warm, they're far apart.
Posted by mum and R

For more science inspiration head over to see Ticia at Adventures In Mommydom

Fine Motor Skills meets Science Sunday: What's inside a pepper?

Take one two-and-a-half year old, one yellow bell pepper and one table knife and let the fun begin.

B loved this activity.  He got to cut the pepper open and explore how it smelt, tasted, felt, sounded and looked inside.  Holding the knife and playing with the small seeds are both fine motor skills activities.  "Yellow" was also the word of the day since it is one colour which he has problems identifying (usually with a yellow object it is "green" to B).  He cut, snapped, broke and (tried to) squish the pepper.  He cut it into ever smaller pieces and counted seeds.  He even noticed that it was wet when we cut it.  Not bad for one small vegetable!
And we even get to save the seeds to germinate with our older kids another time.

Science Sunday: Fun with magnets

This is kind of a learning activity for B that developed a life of its own :)
The original idea - (whilst the older two are at school) Fish shapes in different colours, each with a paper clip on their nose, pick up the fish with the magnet say the colour (we are keeping it simple for our 27 month old and using orange, green and blue).  Simple, classic done by billions of people since the dawn of time - well OK at least since the invention of the paper clip!
Here is what it evolved into:
This magnet thing sticks to these too!

and this

have you seen what happens when you put it in an entire box of these things

"Wow cool!" yep that is a direct quote!

The really interesting thing is that I let him run with it and choose all the objects to test with the magnet and they were all without exception made of metal.
Maybe colours can wait for another day!

Head on over to Adventures in Mommydom for more Science Sunday ideas

Science Sunday: Sunshine and Shadows

Sometimes the most successful sessions are the ones you make up on the spot.
It was an absolutely beautiful day here yesterday and A decided off his own back to get out the sidewalk chalks.     As he came back into the cul-de-sac he remarked that he could see his shadow.  Cue the "oldy but a goody" science lesson.

We first marked a line on the ground and where A's toes where and then drew round his shadow (and Daddys!) Then I asked A what would happen to his shadow during the day. (Answer "Nothing") We came back to it at 45 minute intervals and what do you know the shadow had moved round and got shorter!  Unfortunately Daddy then decided to park his work car on top of our experiment and when he moved it later the sun had gone behind the building so maybe we will choose our site more carefully next time;)

Head on over to Adventures in Mommydom for more Science Sunday ideas