Experiment #6: Does clementine/ orange float or sink in water?

Katli and I are back with another experiment after a short hiatus. I started work in February after the maternity time off. It took us sometime to adjust to a schedule and finally we are here to share an experiment with our favourite ingredient - WATER. Yes my son loves to play with water.

Yesterday we were at my friend's place to celebrate Holi (Indian festival that is celebrated with colors to welcome Spring). The kids enjoyed the most as we let them play with water. On the drive back home, I asked my son the name of the festival he celebrated. His reply was "Splish Splash Festival". He didn't remember the word - Holi but all he recollected from yesterday's party was having fun with water.

Coming to our experiment, let me tell you what we have for you today. We enjoyed eating a lot of clementines/oranges since February. So I planned an experiment with clemetines, green grapes and potatoes.

Aim

To see whether clemetines, grapes and potatoes float or sink in water

Things Needed

• Couple of clementines or orange
• Few green grapes
• Couple of potatoes
• A deep container / bowl filled with water

Directions

1. Prepare the working area. Make sure it can stand all the water spills. I do the experiments in kitchen island. Fill the bowl with water.
2. Put the orange in the water and watch what happens.
3. Put the grapes in the water and watch what happens.
4. Put the potatoes in the water and watch what happens.
5. Peel the rind from the orange and try the experiment again, ask the kid what he/she sees.

What actually happens?

When you put the orange in the bowl of water it floated on the surface. But after you removed the rind,it sinks to the bottom. But that was not the case with green grapes or apple, they sink to the bottom all the time.

The rind of an orange is made of tiny air pockets . When placed in water, they float as the air pockets give it a lower density than water. So when rind is removed, all the air pockets are gone. The orange now sinks as its density is higher than that of water.

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Experiment #4 : How solid substances can rise water level ?

During bed time, I read a story in English and Tamil to Katli. I narrate stories like thirsty crow, greedy fox in Tamil. Those were the stories I grew up listening to. On one particular night, he asked me how water comes up when thirsty crow throws stone into it. I said since stones are heavy and they settle at the bottom. He remembered the previous experiment we did on light and heavy object and said that's because they are heavy. I was so thrilled that he recollected it. 

I continued saying that water flows in-between the stones like how you squeeze through your caterpillar tunnel tent. He smiled. He asked whether we can try doing it at home. I was excited that he came up with the idea for our next experiment. So here we are testing with items from kitchen. 

Aim: 

To check how much water rises with three different sized items

Things needed:

• Three cups and three glasses
• Dry pinto beans, handful
• Dry mung bean, handful
• Dry mung dhal, handful
• Water as needed

Method:

1. Place the bowl and glass against each other as shown in the picture.
2. Fill the glasses with little water, make sure that they are all on the same level
3. Place the beans and lentils in the bowl
4. Ask the child to fill each glass. You can ask the child to count the beans / lentils as they add them. My son could count up to 30. You can go with whatever number the child knows. 
5. They will be excited to see the water come up. You can tell the thirsty crow story and explain it.
6. I left the beans and lentils in water overnight.
7. Next day, we made an easy microwave snack with moong dhal (Haldiram style - recipe here). You can ask the child to help as it involves no cooking. My son helped with this.
8. I plan to show the concept of germination with soaked moong dhal, that's what we do during Navaratri (Indian festival) - more details in the next post)
9. Lastly with the soaked pinto beans (recipe here), I made a simple curry for roti. 

Beans /Lentils are overnight soaking. My son said that they drank the water and became big

Tips to improvise the project:

1. They can learn counting through this experiment
2. Mix the bowls and glasses and ask the child to place it against respective colors
3. Teach them about sizes - small, medium and large
4. Remind them about our experiment on light and heavy object and keep reminding them that these solids settle at the bottom as they are heavy. Sometimes the skin might come of the bean and float, that's gives us a nice opportunity to say that light objects float. For kids to remember concepts, these things need to be said repetitively.

Experiment #3: How to create tornado in a bottle?

What is a tornado?

Wikipedia defines tornado as "A tornado is a violently rotating column of air that is in contact with both the surface of the earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. They are often referred to as twisters or cyclones,although the word cyclone is used in meteorology, in a wider sense, to name any closed low pressure circulation."

My son and I decided to create a tornado in a bottle. We can replicate the effect on a smaller scale with simple items like dish washing liquid, glitters, water and bottle. 

Aim: To create tornado in a bottle using simple kitchen items

Things needed:

1. 1 glass bottle
2. Water to fill it 3/4 th or less
3. Glitters ( I bought this at Walmart)
4. Dish washing liquid 
5. Funnel

Method:

1. Set up the working area. I used a plastic tray to catch the spills.
2. Fill the bottle with water (3/4th or less)
3. Add few drops of dish washing liquid
4. Place the funnel in the neck of the bottle, ask the kid to sprinkle lots of glitter into it (More glitter in the water, more visible will be our tornado in a bottle)
5. Tightly screw the cap to the bottle. Check well so there is no leaks
6. Turn the bottle upside down and hold it by the neck. Spin the bottle in circular motion for some time, about 10-20 seconds, stop and look at the mini tornado forming in the water. 
7. We had to try it few more times to get it right. So keep swirling it and sing to your child for each round you make:

"Round and round the garden

Like a teddy bear

One step, two step

Tickle under there"

What actually happens?

When you spin the bottle in circular motion, it creates a water vortex. You will see water spinning around the center of the bottle. This is due to centripetal force. It is an inward force which directs the object (in this case water) towards the center of its circular path.  This effect looks like a mini tornado.