Science Experiments for 9-Year-Olds

Why Are Interactive Science Experiments Good for 9-Year-Olds?

Experiments are a powerful tool for getting 9-year-olds excited about science. Many science topics are abstract and difficult to understand when read about in a book; however, science experiments can make the concepts come to life. For each of the following experiments, have your child hypothesize and record the results.

Expanding Marshmallows

This experiment will teach your child how a microwave oven works in a unique way. You will need:

• Three large marshmallows
• Three glass plates
• Microwave oven

Have your child write down her observations for each marshmallow and graph the results at the end. Place a marshmallow on a plate and put it in the microwave oven for 30 seconds. Help your child take the plate out (be careful - the plate and marshmallow will be hot). Place another marshmallow on a plate and put it in the oven for 45 seconds. Finally, place the last marshmallow on a plate and put it in the oven for one minute.

Explain that microwaves cause water molecules to spin and move quickly, which heats up whatever you put in the microwave oven. As objects heat up, they also expand. When the marshmallow is put in the microwave oven, it gets bigger because there is water trapped inside the marshmallow that heats up and expands. The longer the marshmallow is in the microwave oven, the hotter and bigger it gets. You can ask your child to find other food items to put in the microwave oven to see if they expand.

Floating Eggs

Teach your child about density with this interesting egg experiment. You will need:

• Two eggs
• Measuring cups and spoons
• Water
• Large spoon
• Salt
• Two tall drinking glasses

Fill the first glass with water until it is almost full. Next, fill the second glass with a 1/2 cup of water and then add about six tablespoons of salt. Gently add more water until the glass is full; do not stir the mixture. Have your child guess which egg will float and which egg will sink, and have him explain his answer. Then, use the spoon to carefully put each egg into the glasses.

He will notice that the egg in the plain water will sink directly to the bottom. However, the egg in the salt water will sink halfway and then suddenly float. Explain that salt water has more density than regular water. Therefore, when the egg was dropped into the glass, it dropped until it reached the salt water and then it floated.

Finding Iron in Cereal

There are cereals that claim to have iron in them, but is it real metal? Test the hypothesis that cereal companies put actual iron in their cereal with this experiment. You will need:

• Two or more cereals (at least one that specifically says iron-fortified)
• Water
• Measuring cups
• Blender
• Very strong magnet from a hardware store

Take the iron-fortified cereal and put about two cups into a blender along with a 1/2 cup of water. Blend the mixture, and then let it stand for about five minutes. Place the mixture into a plastic bowl. Next, get the magnet and place it over the mixture. Your child should notice that there are actual iron bits on the magnet. Tell her that iron is not harmful to your body because it is digestible.

Clean off the magnet with some duct tape and try the process again with another type of cereal. Have her guess which cereals will have iron bits in them and which will not.