This year I’m really lucky to have the opportunity to run a lunchtime science club for the senior students. This is great for me because it gives me a break from teaching new entrants, and great for them because they get to come and just do science. No limitations, no curriculum framework, just pure science. Exploring and experimenting. It’s brilliant. I’ve done two sessions so far.
I’ll link some videos here so that if you want to give this a shot, you can. The way I format it is as follows: whoever turns up to each session first gets to do that week’s experiment, and I take a certain number depending on how much equipment I’ve got/how controlled I need to keep it. It can be different kids each time – each week’s investigation is isolated from the week prior.
I change up what we do, too, e.g. the first week was a challenge for them to recreate my results, the second week was more led by me. The third week, I plan to give them materials and instructions and have them work in groups of three to do experiments. They’ll then present back to each other.
For term 2, everything is material world (chemistry) based. In term 3 we’ll be looking at the physical world, and then in term 4 we’ll get into living world experiments.
The milk investigation
milk
dye (food dye or regular dye, both work)
dishwashing liquid
Pour milk into a dish – it doesn’t need to be deep. Add drops of dye to the milk. Then, put a drop of dishwashing liquid into the middle of the milk. The milk will move away from the dishwashing liquid and the dye will indicate what’s happening. You can add more dishwashing liquid to different parts of the dish and the reaction will happen again on a smaller scale.
I made a video of myself doing the experiment prior to running science club. When the kids turned up I showed them the video, but only the reaction itself – not the adding of reagents.
Then, I buddied them up and gave them a bunch of reagents: milk, dye, dishwash, but also water, vinegar, baking soda, salt and sugar. We discussed the properties of all the reagents and what we knew about them, and then I asked the kids to recreate the experiment. It took them a while to get to the dishwashing liquid, but they were thrilled when they did. They had a few tries at the experiment and we talked about what other things might have the same effect (FYI: spray and wipe does not, which surprised me).
Surface tension medley
1. Drops on a coin
pipettes
coins
water
How many droplets can you fit on a coin using a pipette? (Hint: do the tiniest droplets you possibly can to max your score.) Once a coin is “full” you’ll be able to see that it’s created a big bubble of water sitting on top. Surface tension is what allows the water to go above the level of the coin.
2. Swimming fish
cut out paper fish
water in a large bowl/tray
dishwashing liquid
Put your fish in the water. Put a drop of dishwashing liquid behind it and watch as the fish swims away from the dishwashing liquid. This happens because the dishwashing liquid breaks the surface tension, causing the water to move and take the fish with it.
Interesting note: you can’t do this with the same water twice, presumably because the dishwash being present doesn’t allow it to re-establish surface tension. You could test this out further by pipetting some out onto a table and seeing if it creates beads like regular water, or if it spreads out.
3. Sinking paperclip
container of water
paper clip
tissue
dishwashing liquid
Sit the paper clip on the surface of the water. Note: this is really hard, so one way to do it is by sitting tissue on the surface, then paper clip on the tissue, then push the tissue out from underneath so the paper clip is left floating. Add a drop of dishwashing liquid to the water and the paper clip will quickly sink. This happens because … you guessed it! The dishwashing liquid breaks the surface tension, which the paper clip is relying on to sit on the surface.
4. Jar and card
jar
water
thick card, cut big enough to cover the mouth of the jar
Fill the jar with water until it is overflowing, and make sure it has a surface tension bubble sitting on top. Put the card onto the mouth of the jar and press down so the water starts to soak into the card. Very carefully, turn the jar upside down, supporting the card, and then release support. The card will keep holding the water in the jar.
The water suctions the card onto the jar, creating a seal. This will hold pretty well and you can pass it around, counting how many passes you can do before it gives up (it will eventually). You can also give it a bit of a shake … or a bit more of a shake. Play around and see how secure you can make it.
So there we go. Two sessions of science club! The second was my favourite – the kids were so enamored with the drops on a coin game that they really had to be convinced to stop. Everyone wanted to beat my record of 70 drops on a coin.
One of the boys I had this week has a huge personality, so naturally I handed him the jar and card and told him to shake it. He did, and was so delighted to find that it was possible, that he shook it harder and higher until he eventually doused himself. He was positively gleeful about the whole thing and I don’t think I’ve ever laughed so hard.
We’ve also set up a hydroponic kumara, and we’re monitoring its progress week to week. Not much growth as yet!
Auckland BT: science edition 