Why does talcum powder float on water surface

Now take a bar of soap and touch one corner of it to the water surface near the edge of the plate. The talcum powder will be pulled suddenly to the opposite side of the plate. If you're struggling to do this with the bar of soap, check out the similar experiment in the links below. They have a different method. The talcum powder doesn't dissolve in the water, and it doesn't sink; it lies on the water surface, supported by surface tension. The effect of the soap is to break that film of surface tension.

At the place where soap touches water, molecules of water attract molecules of soap rather than each other. Meanwhile on the other side of the plate, water molecules still attract each other. If you mix some soap with water and make a water droplet on your counter again, what do you think the shape would look like? Give it a try! The soap once again breaks the surface tension of the water, causing the staple to no longer be supported.

By understanding how soap breaks down surface tension in water, you have the ability to clean off your dirty dishes after you eat. Baking powder is Sodium Bicarbonate a polar compound that is particularly amenable to water a polar solvent. So Baking powder will dissolve faster than a non-polar powder like Talcum powder. Also baking power is very finely ground and will present a large surface area to the water which hastens dissolving. Salt in comparison although a strongly polar compound is course ground and will take longer to dissolve.

Log in. Pica Disorder. Study now. See Answer. Best Answer. As the talcum is wet it will sink. Study guides. More answers. Q: Why does talcum powder float on the surface of water? Write your answer Related questions. Does talcum powder float on water? Why does not talcum powder dissolve in water? Is talcum powder soluble in water? Will talcum powder dissolve in hot water? Use the sieve to evenly distribute a layer of lycopodium powder over the surface of the water.

Push one finger straight down below the surface of the water and straight back up. Observe the dust on your finger and the fact that your finger is still dry. Now insert four fingers straight down into the water and observe, through the side of the beaker, the bubbles attracted to your hand.