I can't say that I enjoyed science much in school. I can remember the most incredibly dull and dry textbooks - but other than being bored - I don't remember much of what I was actually meant to be learning. I thinking science is really better as a hands on subject, and I know more and more schools are treating it this way as well - plus the quality of textbooks has really gone up, but science experiments at home are still a good way to have a bit of fun and learn something in the process. And for those of us who home educate science experiments can really add a whole new dimension to our curriculum. I'd like to share a few of our favourite tricks, and with any luck some of you will post a few of yours as well.
Before we go any further - these activities require parental supervision. If you are a child reading this - please talk to your parents about these projects before starting one. If you are a parent, I think common sense dictates that you take some involvement in this. Some of these experiments involve chemicals, flame, or bacteria. Please be sure all safety precautions are taken and don't forget hand washing.
1. RUBBER EGG:
1 raw egg
1 cup vinegar
This experiment is as as simple as they come. You simply place a raw egg in a cup, cover it with vinegar and wait for a day or two.
Vinegar is an acid and as such dissolves calcium. The egg shell will get soft and rubbery, and over time the egg will grow larger as more vinegar is absorbed by the egg. We used brown eggs and the first thing we noticed was that the colour wiped away quite quickly. Within 24 hours, the egg was becoming quite rubbery. By the following day is was very soft and rubbery.
Real life applications?
Egg shells are not the only thing made of calcium. Our teeth are made of calcium too. I explained to my sons that acidic drinks like coke can also damage our teeth. I also explained that bacteria produce acid when we don't brush our teeth properly. This acid attacks their teeth in the same way that the vinegar eats up the egg shell. This experiment not only teaches the children about chemical reactions - it is great way to demonstrate how tooth decay works.
My sons loved this experiment - so much so that they are extremely loathe to give up their project, which has been sitting for days growing more rubbery every day. We are nearly down to thin membrane that surrounds the egg now. Eventually it may burst so I only allow the handling of this project outdoors or over the sink. I'm hoping the vinegar will prevent rotting - but I don't want to find out by ending up with rotten egg all over a rug. As an added plus - this has encouraged tooth brushing as well. They don't want their teeth dissolving like the eggshell.
UPDATE: I had never kept one of these eggs so long, but we still have this one going. The shell has completley dissolved, leaving the egg enclosed only in a thin transparent membrane. It is rather squishy, and I'm sure would burst of squeezed but the boys love it. You can see the yolk and egg white - which is now turning slightly greenish as we added quite a bit of food colour to the vinegar. They call it an alien egg.
2. LAVA LAMP
water or tonic water
fizzy tablets - such as cocodamol
Light source -torch, clack light or candle.
Clear jar - preferably glass. We used a mayonnaise jar.
Measurements depend on the size of your jar but you want the majority of the jar to be filled with oil. Add a small amount of water to a tea cup - 1/3 full should be fine for a small jar. Drop in some food colour until you have a nice dark colour - or if you have a black light - you can use tonic water instead - tonic water glows under a black light with a faint purplish hue. Do not use food colour if using tonic water. Pour this on top of the oil add a couple of cocodamol or other fizzy tabs, seal the lid on tightly and turn the jar upside down. The coloured water will rise through the oil and fall back down again. A light source makes this much more attractive. The principle is that oil is lighter than water, but carbon dioxide is lighter still and the lightest substance will rise to the surface. a quick shake will get going again several times, but after a few minutes you will need more fizzy tabs.
Precautions: Obviously water and electricity do not work. Do not use a mains powered light underneath the jar. A torch works better, or even a candle behind the glass. Children can get carried away shaking, if using glass the usual safety measures apply.
A base for your volcano
red food colour
The base for your volcano can be as simple as a paper cup or cut of bottom of juice bottle, or as complex as a paper mache construct over a board complete with prehistoric scenery or even a small town. If using paper mache, let dry thoroughly before painting. Then dry again and paint with several layers of clear varnish to help protect it from the "lava". Wipe dry immediately after use. A plastic cup should be built into the structure to hold the liquid.
Mix white vinegar with a few drops of red food colour and pour into the cup add a good sized spoon of baking soda. The "lava" will erupt and pour down the sides, add enough and it will engulf small towns, or hapless dinosaurs. This teaches about chemical reactions, gasses as well as actual volcanoes.
Precautions: This is messy and food colour may stain.
2 clear plastic bottles. I prefer 2 litre, but most sources recommend smaller ones.
+ one of the following choices:
plasticine + duck tape
tornado tube A small bit of plastic that connects two bottles to create a vortex cost £3 -£4 from ebay or Amazon.
length of radiator + hose cork with large hole drilled in it
Optional: food colouring, glitter, sequins.
Single bottle method: 1 bottle + plastic cap with large hole, made by sticking a hot nail through it.
The basic idea is very simple. You fill one bottle most of the way up with water. You can add food colour, sequins, and or glitter if you wish. The other bottle is left empty - well not exactly empty - it contains air. You simply connect the two bottles with the water filled one on the bottom. The tornado tube is the easiest - you just screw the tube into the two bottles. You can do the same thing though with plasticine and duck tape. Smash a blob of plasticine into the neck of the bottom bottle, leaving plenty of extra sticking out. Pole a large hole in it with nail. Stick the other bottle on top and tape well . It will likely leak some - but it will work for awhile. Another option is to find a length of radiator hose in the correct width to fit over the bottle necks, slide the hose over the first bottle. Put in a cork with a hole drilled into it. Slide the second bottle over the cork and under the hose.
Now that the vortex maker is assembled all you do is quickly turn the whole lot over give it whirl the top one about to get it started and you have a tornado as the air rises while the water descends. This is basically the same principle as a real tornado, but with a real tornado hot air would be rising while cold air is descending, creating the vortex.
The single bottle method does not work as well - but it is easy. You simply fill the bottle up, hold your finger over the hole in the cap, flip it over, give it a few whirls and remove your finger. This one works best in the bathtub but be sure they keep the bottle over the tub - not the floor.
Precautions: There isn't much danger with this one, but the water may leak out, and if using food colour you may get stains.
Tips: If making a fancy vortex with a tornado twister and glitter etc... you might add a very small drop of bleach to keep the water from growing algae if you plan to keep it assembled for long.
MAGNET CAR RACES:
small wheeled car or train
small magnets preferably neodymium and tape, unless using wooden trains with built in magnets.
Two good powerful magnet wands
This shows how magnetic propulsion work - the same principle that operates monorail trains, teach children about magnetic poles and it's just plain fun. If you have wooden train cars with magnets, you are already half way there. We did this with Hotwheels cars too, taping a small neodymium magnet to the car. All you do is take the magnet wand and turn it such a way that the magnets are pushing against each other. Then by hovering the wand over the vehicle - you drive it without touching it. You can races or navigate obstacle courses, or simply drive wooden trains around their tracks
Agar or unflavoured gelatin
Plastic take away dishes with lids
This is best done with agar, a medium sold for growing bacteria, but plain jelly can be used in a pinch. Agar will cots about £4 from ebay, £6 from Amazon - but you get more, or may be found in health food stores. I am quite certain flavoured jelly cubes would work too, but dread to think what would happen if a small child ate this.
You mix up your medium, agar or jelly and put it into plastic take away dishes. Let cool and harden. Next you place mosit samples from various locations you think would harbour bacteria. A cotton swab rubbed over unbrushed teeth works great as do slightly moistened unwashed hands. If you have a few dishes you can see the difference by placing unwashed hands on one, and then carefully washed hands on the next. Try damp swabs of the bottom of your refrigerator and things like the toilet seat too ( surprisingly the toilet seat usually yields very little. label your dishes, cover and place in a warm place to incubate. Be very certain that pets and small children can not reach this!
A week later you can compare various cultures and see what had the most bacteria. ALWAYS wash hands after handing these and dispose of the containers after use.
Precautions: You are growing bacteria - most are harmless but not all. this could make some one really ill if eaten so be careful with this.
Bacteria farms above
Various antibacterial products
For each dish compare two products squirt on various antibacterial cleaners and see which ones kill your little creatures the soonest. Again - ALWAYS wash hands - dispose of all farms containers when finished.
STINK BOMB FROM HELL
bag of sulphur ( £3 from ebay)
You can make a simple stink bomb by poking a hole in an egg and letting it sit for a few weeks but this is truly the stink bomb from hell.
Place the candle in the tin. Fill with small shreds of paper and sulfur and light. Don't worry about running this takes awhile. As the candle burns down it reaches the sulphur. The sulphur begins to boil and melt, but the smell wasn't as bad as we had thought, In fact the children were very disappointed. The stench continued to rise and we stood back a bit, but the wind was blowing most of it away. My neighbour came out and looked around and went in, I didn't think anything of it. Then it hit us. OMG it had to go out. My youngest was disappointed he wanted to let it keep burning but he was upwind of this.
Only once we had extinguished this did we realise our mistake. The wind was blowing the fumes away - right into our house! And likely the neighbours too. The smell was awful and took hours to dissipate as I burned very candle we owned. But that wasn't all - we had become walking stink bombs. If you ever want o clear crowds and get through a queue quickly, this is just the trick - people will move away from you like you have the plague. This definitely called for lather, rinse and repeat, several times with shampoo as well as washing every bit of clothing.
What did they learn? Well I can't say that this in itself was the most educational, but having gone through a number of experiences to find the worst possible stink, we did learn scientific method of trial and error and one experiment after another. We also learned if you keep at it you reach success eventually. If you can call it that.
The boys are dying to try this again. I don't think my neighbours would appreciate it. But maybe we can make one and use it up on the green - right where all the trouble takes place in the summer- we may just have found a cure to recreational rioting here!
I have so many other experiments, but I had better draw this to a close before I end up with a book rather than a review. If you have any questions at all - please ask and I hope to read some of your ideas soon too.