Request or contribute your recipes here. You can also try doing a search, as there are some old recipe posts which have not or cannot be moved over to this forum.
My favourite teacher has just asked for a prac which involves exploding flour to demonstrate surface area and rates of reaction. Has any one heard or done this and with what success and how dangerous is it????
I did have to point out that we could not take a bunsen burner outside the lab I really don't think I have enough tubing for that lol.
Hi
Have seen it done by Dr Karl
what he did was put it in a filter fun and had a long piece of tubing on the end and then he blowes it into the air and the lights up the powder with a big fire ball
Noona
There is also a mythbusters episode that explores this concept they shoot flour and saw dust out of a cannon and light it with a flare. GIANT fire ball. Problably not very helpful though
Hi everyone,
We do it here with a large coffee tin with a hole in the side at the bottom, and a piece of tubing stuck in it. You then place a small quantity of flour in the bottom of the container (not sure how much exactly) and then carefully place a lit tealight candle in the bottom. Place lid on and a "huff" of wind through the tubing should kick up the flour and cause an explosion that blows the lid off the tin. I would need to check with the teacher that does it as to how much flour he uses, and can post a photo of the "apparatus" if you wish.
Hope this helps,
Lou P.
We do this outside, with a coffee can and a candle, as mentioned by Loopy. Works best with a l-o-o-ong length of fine (aquarium) tubing, so as to retain the eyebrows. Coffee whitener works too. Really any fine particulate is OK.
We have used custard powder with varying results. It needs to be done outside as it produces some interesting exploding flames. As for demonstrating surface area and rates of reaction I think your teacher is just out to demonstrate the Big Bang Theory.
Lyn.
We have used custard powder, a spoon full in a funnel attached to a long piece of tubing and give one big puff of air down the tubing and the result is a big fireball over the bunsen. The kids love it but we dont tell them it's custard powder, could you imagine the mess they would make at home blowing custard powder over the gas stove!!!! There would be some angry parents ringing the school the next day for sure.
We have it in a specially marked jar that reads "fireball powder" and we tell the kids that's what it is called when we buy it from the chemical company and they wont tell us what's in it!
just got to love that label. "Fireball Powder" I just love it. We had a lady who was on a diet so only had low fat milk, she was so sick of people just helping them self to her milk. She put breast milk only. No one ever went near that bottle.
Regards Labbie
Lab Manager/Lab Tech, mind reading etc etc
Now retired
Hi. Jen, Just how far away from the bunsen should you be to do this and do you prop the funnel up in any way? Is the fireball really large? How much of a mess does it make? Am looking for interesting things to demonstrate for Year 7 Open Day but don't want to suggest anything that might be too unsafe.
Lyn.
Hi Lyn, Another good one for yr7 orientation day, show how dangerous gas can be
A trough of water and bubble bath, with a bunsen burner hose, pump gas into the water, 1 meter ruler with a large scoop attached to one end, and another with a candle. Get the kids to scoop up the bubbles and light, fireball. Kids love it!
hi lyn,
the funnel is held just below the bunsen burner, probably about a foot away. The teacher just held it in her hand and puffed into the tubing which was about 1m long. We did it inside and had the kids stand well back. It did make a bit of a mess with some custard powder going on the bench. The teacher was an ex scitech demonstrator and she had lots of experience doing this all over WA.
pkij - I dont think she has ever tried it with a candle and she isnt here anymore (moved to another school, not blown herself up!).
Macca - we run hydrogen gas (zinc and HCl) through a beaker of dishwashing liquid and the kids collect a spoonful of bubbles and hold these over a candle. They love it, a bang and flames!
Hi Pilar,
Try as I might I just can't attach a photo as we now have some sort of new program for pictures which unfortunately I cannot master ... But if you punch a hole in the side of a coffee tin (1kg) approximately 3cm up from the bottom and large enough to fit bunsen tubing through. Approximately 50cm of tubing should do it. Inside you place a petri dish full with flour, and beside that a lit candle. The tubing inside the tin should be in the petri dish so that when you give a good puff it really kicks up the flour. Place the tin lid on, give a good blow and voila! exploding flour. I am so sorry that is the best I can do for you for now. I must say the custard powder sounds pretty exciting. We shall give that one a go here.
All the best,
Lou P.
If demonstrating the Big Bang Theory....ideally outdoors
using a paper punch.....punch holes in about 7 different colours of paper.
Put the "confetti" in a balloon.....inflate balloon and tie off.......burst the balloon then have students make observations eg.
* does one particular colour travel further than the rest ( you can use different thickness
papers )
* scatter pattern - does it clump or spread evenly
* does size of inflated balloon vary the scatter pattern
* distance travelled
has just asked for a prac which involves exploding flour to demonstrate surface area and rates of reaction. Has any one heard or done this and with what success and how dangerous is it????
I really don't think I have enough tubing for that lol.
is just out to demonstrate the Big Bang Theory. 
But if you punch a hole in the side of a coffee tin (1kg) approximately 3cm up from the bottom and large enough to fit bunsen tubing through. Approximately 50cm of tubing should do it. Inside you place a petri dish full with flour, and beside that a lit candle. The tubing inside the tin should be in the petri dish so that when you give a good puff it really kicks up the flour. Place the tin lid on, give a good blow and voila! exploding flour. I am so sorry that is the best I can do for you for now. I must say the custard powder sounds pretty exciting. We shall give that one a go here.
