This weeks theme is color. Naturally, we will be doing some cool color based experiments. First up was “Alkaline, Acid, Base.” This experiment called for everyday things you likely have in your kitchen or can easily pick up. Purple grape juice, lemon juice, and baking soda. Grape juice is an indicator liquid meaning it is a neutral liquid that changes color when its acid level or alkaline level is increased.
Set up is easy. Take two glasses and put about 1/4 cup of grape juice in each. In one glass add the juice of one lemon. Note the change. The color of the juice should change from purple to red. In the next glass add about 1/2 tablespoon of baking soda and stir. The grape juice will bubble and change to dark greenish blue color.
If you add lemon juice to the blue liquid the color will change back to purple. If you add baking soda to the red liquid it will also go back to purple. If you want to add another component to this experiment include ph test strips and add the lemon juice or baking soda using .5ml droppers measuring the ph after each addition.
Here is a video of us doing the experiment. Below are some questions to ask your student.
Alkaline, Acid, Base Experiment Video.
How do we use color to give us information? (Traffic lights, cooking, fashion ect.)
What color is the grape juice?
What do you think will happen if you add lemon juice? Baking soda?
What happened when you added the lemon juice? Baking soda?
How can we turn the lemon juice mixture back to its original color?
What is the ph of the grape juice?
What is the ph of the juice after .5ml of lemon juice?
How many ml of lemon juice did it take for you to notice a change in the color of the liquid?
What is the ph of the juice after .5ml of baking soda?
How many ml of baking soda did it take for you to notice a change in the liquid’s color?
This was a fun experiment for the kids and they really enjoyed watching the colors change.