Aim: To observe convection in a liquid
Equipment: 200 ml beaker, water, tweezers, a crystal of potassium permanganate, a drinking straw, Bunsen burner, heat mat, tripod and gauze mat.
Method: 1. Set up a bunsen burner on a heatproof mat. Put the gauze mat on the tripod but leave it just to one side of the Bunsen burner.
2. Fill a 200 mL beaker with 150 ml cold water.
3. Place the beaker on top of the tripod and gauze and allow it to settle for a few minutes.
4. Carefully insert a drinking straw down one side of the beaker, ensuring the straw is touching the bottom of the beaker. Be careful as you do not want to disturb the water too much.
5. Using tweezers, drop a crystal of potassium permanganate down the inside of the straw. Wait for the crystal to settle on the bottom of the beaker.
6. Very gentle, so not to disturb the water, remove the straw.
7. Light the Bunsen and slide it under the tripod so that you are only heating the outside of the beaker where the crystal is. Observe.
Observation: The potassium rose up and scattered across the top and turned the water purple.
Explanation: What I saw was the potassium permanganate rose up to the top and fille the water purple at the top and the bottom.
A very well laid out blog post here Gabriel. I would love to see a picture or two on these as well. Also make sure your explanation talks about the science of what you see. For example, the potassium permanganate gets heated up and rises- which is what we see. But keep up the good work!
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