Friday, January 25, 2013

Grow tomatoes, grow!

 Grow some tomato plants to later plant outside and learn about germination and photosynthesis in the process.

Appropriate Age Level
3+ for the actual experiment
5+ for concepts

Materials Needed
Planting pot(s) or plastic cups
Tomato seeds
Camera to take growth pictures with

Science Concepts Learned
Germination (1) - (see picture below) the process where a seed grows to become a seedling. For a seed to do this it needs water, oxygen and to be at certain temperature. 

1.The root emerges through the seed.
2.The part of the seed called the hypocotyl pushes it way out of the soil.
3.The hypocotyl straightens itself out.
4.Leaves begin to form.

Photosynthesis -  (see photo below) the process where plants convert energy from light from the sun into chemical energy that can be used by the plant.  

The reaction is the following (3):

carbon dioxide + water  ------->    sugar + oxygen 


1. Set out cups or pots and fill the pots with dirt (a starter mix for plants is recommended) as many as you want though think about seed crowding.  

2. Plant tomato seeds 1/4 inch deep in the dirt (2).

3. Water the seed/dirt mixture to make it soggy but not swampy.

4. In 5 to 10 days germination should occur. Take a picture of the potted seeds each day in this range and discuss the germination steps listed above in the terms section. 

5. After germination has occurred, weekly take pictures of the plants.  

6. After a few weeks compare the size of the plants with the pictures taken and from them you can talk about photosynthesis and how the light and water has helped the plant to grow. 

7. Continue growing the plants, and you can either transfer them to larger pots and keep them inside or you can transfer them outside if it is the right time of year. 

8. Enjoy the fruit you get from this practical example of science!

Time Allotted 
5-10 minutes weekly


Monday, January 7, 2013

Cleaning Reaction: Acid Base Chemistry

Appropriate Age Level
3+ (more depth for older children) 

Science Concepts Learned

Acid Base Reaction - a neutralization reaction where enough base is added to an acid to neutralize it into a salt and water

The following acid base reactions occur when vinegar(CH3COOH) and baking soda(NaHCO3) react:

A. CH3COOH + NaHCO3 ===> NaCH3COO + H2CO3

      (vinegar)    (baking soda)  (sodium acetate)  (carbonic acid) 
B. H2CO3 ===> CO2 + H2O
(carbonic acid)  (carbon dioxide) (water)
Overall:  CH3COOH + NaHCO3 ===> NaCH3COO + CO2 + H2O

                (vinegar)    (baking soda)  (sodium acetate) (carbon dioxide) (water)

Compound Reaction - reaction where there are intermediates that are not in the products or reactants

Decomposition Reaction  separation of a chemical compounds into elements or simpler compounds

Exothermic Reaction - a chemical reaction where energy is released in the form of heat or light.   

Materials Needed

1/2 cup White Vinegar

1/2 cup Baking Soda
two containers for each substance
optional: liquid measuring cup


1. Pour 1/2 cup of vinegar into a container, one with a lid for smaller children.  Measure out 1/2 cup of baking soda and put into another container. 

2. Now, this is your choice.  You can either carry out the experiment this in a bowl or on a spot that needs some cleaning. For more containment use the bowl, but if you want something cleaned along with science being learned then by all means be creative.

3. Add a tablespoon of the baking soda to the container or designated spot.  Spread it around evenly.  Add a tablespoon of vinegar on top of the baking soda and watch it react.

4. Rinse out and dry the container, or choose a different spot to clean and repeat, this time explaining the reaction happening :

A. CH3COOH + NaHCO3 ===> NaCH3COO + H2CO3
      (vinegar)    (baking soda)  (sodium acetate)  (carbonic acid) 
B. H2CO3 ===> CO2 + H2O
(carbonic acid)  (carbon dioxide) (water)
Overall:  CH3COOH + NaHCO3 ===> NaCH3COO + CO2 + H2O

                (vinegar)    (baking soda)  (sodium acetate) (carbon dioxide) (water)

5. Depending on the age of the student you can go into as much detail as you want, you can add in the stoichiometry with the associated compounds, you can explain how this is a compound reaction versus a one-step reaction, you can explain how this is a decomposition reaction and go into detail about what an acid and a base means.

Time Allotted 

10-15 minutes