Microwaving Soap
When you warm up leftovers, have you ever wondered why the microwave heats the food and not the plate? (Well, some plates, anyway.) It has to do with the way microwaves work.
Microwaves use dielectric heating (or high frequency heating) to heat your food. Basically, the microwave oven shoots ‘light beams’ that are tuned to excite the water molecule.
Note: The ‘light beams’ are actually high-energy radio waves, but this can get confusing, because most people think radio waves are sound waves, which is not the case, so I refer to them as ‘light beams’, but you can use the term ‘radio waves’ if you’re kids are already in tune with the electromagnetic spectrum.
Anyhow…foods that contain water will step up a notch in energy levels as heat. The microwave radiation can also excite other polarized molecules in addition to the water molecule, which is why some plates also get hot.
Here’s what you need:
Please Login or Register to read the rest of this content.
Just as awesome the “Plasma Grape”! We used Dove soap and not Ivory but it still worked wonderfully? Is there a reason that two different soaps worked the same?
sevy keble
Hmmm… sounds like Dove has air mixed into it as well… you’re actually getting less soap for your money when you buy these brands, but they are the ones that work in this experiment the best!
This is SO cool!
Holly Thomson
I love watching the the soap form weird shapes in the microwave.
Holly Thomson
What fun! We found an old bar of Ivory soap (nobody knows where it came from!) and used it. It was cool to watch and my boys loved it! The boys said our microwave oven must be more powerful than the one on the video demonstration because the soap actually started to burn in just over a minute! I think it might also be because we don’t have a rotating plate in it. (It’s pretty old.)
This was such a great start to our Science at home. I was actualy at work and wanted my kids to get chores done. I told them I had a great surprise in store for them when chores were done. I sent my oldest daughter the link and directions and they called me when they were done with the experiement. They LOVED it!! My son even took a bath after with the “cool” soap.
So, not only were chores done and Science covered, I had a clean boy when I got home
We tried two bars of Ivory and neither puffed up like on the video. We also tried some other hotel bars. One with perfume and it burned a little. And it left a very unpleasant smell in our house for a while.
I thought maybe our Ivory was too old, but Mary Beth posted using an old bar, so not quite sure what happened. It just cracked.
But the kids had fun doing this experiment anyway.
Sometimes if an ‘old bar’ stays sealed enough, the water vapor inside the bar will remain IN the bar, otherwise it will evaporate out over time and when you place it int he microwave, the microwave has no water molecules to excite so it winds up cooking and burning the bar.
i worked great!
We used some perfumed hotel soap and it was very impressive. Foamed up beautifully! The odor afterwards sent us scurrying to open windows and turn on the fan. All the kids grabbed their gift candles from Christmas and stuck there noses in the jars for a bit. Wish I had also gotten a picture of that!
That sounds so fun… you can always post pictures here:
http://sciencelearningspace.shutterfly.com/
Sorry I have not been active here for a while
, but I am back! Btw, we did not do unit 8 because the chemicals accidentally got taken to storage. 
. but, I’m back! 
Hey, there – welcome back! Don’t worry – the Chemistry unit will be up forever… so you have time.
This worked great. The bar of soap became a huge mound of puffiness. This soap will be fun to use in the bath.
We used a old bar of ivory soap so it didn’t work very well. It had some water so it expanded a little bit but not a lot.
Martin Betts
Our bar of Ivory grew so much we had to stop it mid-cycle, remove all the fluff and put the remainder back in for another go at it. We enjoyed it so much that when Dad got home we dragged him to the microwave to watch another whole bar (stopped mid-cycle and restarted again!). Thanks for an enjoyable experiment!
Yesterday finally got started on Super Charged Science, and we picked this as our first experiment. Wow! this science is going to be fun! Our Ivory soap bar was fresh and moist, and it just about filled the microwave.
well, this was our first time… and guess what it was great! i have five fearless boys and the 7 year old put his fingers right on top of the hot soap… so DONT touch soap is really hot inside… VERY FUN!
It was so COOL!!! After the experiment, the soap looked and felt like tissue.I still used it as soap!
We used the Castle soap you get from CrackerBarrel. Worked like a charm and added lots of questions. Great to see the kids so excited about learning! Makes an interesting shape for the soap dish.
This was a fun experiment! We compared a fresh bar of Ivory soap and a similar-sized bar made from shavings from Ivory soap (the shavings were left over from a carving session we had). We looked at symmetry of expansion and discussed possible effects – one seeming to be placement of the bar on the plate and the plate within the microwave, We need a few more bars to get any conclusive findings though.
You’re right – placement in the microwave (both horizontally and vertically) will make a difference, as well as the power setting. This isn’t as crucial as with the Plasma Grape experiment, though, as the bar of soap is much larger than the grape-skin bridge. Have fun!
We had a blast doing this experiment and have then enjoyed ‘fooling’ friends with our whip cream mound on the kitchen counter or in the bathroom. The only reason to stop doing this over and over again, is running out of soaps. Not sure how many mounds of soap I am willing to store in the bathroom ….
We did this awsome experiment 3 times. The aroma of Ivory filled the house and the microwave. A great tip to get rid of the odor is just put a tablespoon of lemon juice in a cup of water let it heat in the microwave for a few minutes and the odor should be gone.
That was awesome! I was on the edge of my seat! Jasmin & Isabel