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Demonstrate just how exciting science lessons are, and your students will quickly decide that science is an incredibly engaging subject - especially when they realize that it is possible to reproduce these science tricks at home to amaze their family and friends.
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Capture the Ice Cube
- ice cube
- water in shallow dish or glass
- various other objects or materials (for example, flour, chalk, sand, rocks, pencils)
Before beginning the science activity, give each student (or pairs of students) a string, and an ice cube floating in a glass of water or shallow dish. Ask them to find a way to pick up the ice cube using a string. After several minutes, ask students to share various methods tried. You may want to make a list, or graph the number of students that tried the same method(s). You can also graph the number of students that were successful versus the number of students that were not. For older elementary students, you can convert this number into percentages.
Now, demonstrate a solution. Here's how:
- Place the string on top of the ice curve and sprinkle salt lightly over the top.
- After a few seconds, place the string on top of the ice cube.
- Lift the ice cube right out of the glass or shallow dish.
Here is how it works:
Adding salt to the ice causes a drop in temperature, which slows the melting rate of the ice and increases the freezing rate. The result is that the ice melts more slowly after the initial addition of the salt, and allows the string to adhere to the ice.
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- Dish soap
- A bowl filled about 2/3 full of water
Sprinkle some pepper on top of the water. Tell your students that you are really a magician in disguise, and that you can make pepper run away. Rub some of the dish soap on your fingertip. When you dip your soapy finger into the water, the pepper will quickly move to the sides of the bowl. When you remove your finger, the pepper remains at the sides. Your students will be amazed...especially when you explain that it is really science at work - not magic!
Here is how it works:
The pepper particles are being held up by the surface tension of the water. The soap reduces the attractive forces of the water molecules, thus reducing the surface tension. As the water pulls away from the soap, it carries the pepper along with it.
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Using these elementary science activities for the first day of school will not only peek the interest of your students, it will show them that science is more than just theories and formulas. Demonstrating the practical aspects of science will make them begin to think about science in a whole new way.
Here are some other cool science experiments to try:
- Ideas offered in this article are based on the author's experience as a classroom teacher.