Science Electives

We're fortunate at our school to run electives one afternoon a week for the whole of Term 3. One of the electives on offer is science experiments.
For our first session we looked at surface tension and related experiments. Check out this great experiment from Brainiac via You Tube!



During this lesson we made our own "Non Newtonian liquid" using cornstarch and water. It was amazing because when we hit it quickly it was rock hard and yet it also became runny enough to slide off our hands, as these pictures show!










MILK SWIRLS and SURFACE TENSION
We also had a heap of fun making milk swirls when we took a saucerful of milk, added a couple of drops of different food colourings and then a drop of dishwashing detergent to the centre of the milk. Wow we made some fantastic patterns and had great fun seeing if we could get the swirling to continue by adding more dishwashing liquid, more milk or more "anything"!

Can you believe it, we're also MUMMIFYING SAUSAGES! Yes, that's right, we are dessicating(drying out)a variety of sausages with bicarbonate of soda; a bit like the Ancient Egyptians did when they mummified their Pharoahs.
Each week we recoat out sausages in fresh bicarbonate of soda because we have found that the bicarb. becomes quite saturated and encrusted from the fluid it is drawing out of the sausage. We also measure the weight, length and circumference of the sausages to see if there are any differences from week to week.
Follow this table to see what the results show on RD,O and SL'ssausage:

Pre mummification
Weight: 0.1g
Length: 6cm
Circumference: 8.5cm
Features:Colour Red
Smell:chicken but not roasted
Teacher’s/student’s comments: RD: I can't believe we actually get to do this. Can we put the insides in a sarcophagus too? Mrs H: NO!

1 week later
Weight:0.1g
Length: 6cm
Circumference: 6cm
Colour:Dark red
Smell: mouldy dead rat
Teacher’s/student’s comments: Not sure about the accuracy of your circumference measurements, boys...we’ll have to check them this week! (Mrs H)

Have you ever tried making icecream using ice, salt and plastic packets?
We did last week.
Into one small packet we placed 1/2 cup of milk, chocolate/peppermint or strawberry essence, a spoonful of sugar...and zipped it closed.
This small packet we placed inside a larger packet with a couple of cups of ice and about 6 spoonfuls of salt. We ziplocked this one closed as well and then started squeezing the milk against the ice.
Some of us squeezed a little too enthusiastically and our bags popped (luckily we were doing this outside!) but those who persisted squeezing GENTLY ended up with some delicious icecream.
One packet of ice contained no salt and that one never became ice cream...it remained milk. Why was this do you think? We know..but we'd like to hear your comments! (A clue...it has to do with the effect salt has on the melting point of ice)
So, with very cold fingers and full tummies, we think we could make quite a lot of money from our new found knowledge!



Static Electricity
Have you ever bounced on a trampoline and touched a friend, only to have them shock you?
We explored this shocking effect by looking at the flow of charge from a positively charged body to a negatively charged body. At first we tried using our socks to charge the balloon but as this wasn't particularily successful at giving a big enough charge, we caught onto the idea that by rubbing the balloon on our own hair, we could create a bigger charge.
Using the positively charged balloon we then lowered it over a dish of pepper and made the pepper dance by being attracted to the balloon. When we were quiet enough we could even hear the crackle of the pepper as it was attracted upwards onto the balloon's surface. Of course, if the balloon touched the sides of the dish, it was discharged and would no longer attract the pepper upwards.