BENCH RESEARCH INSTRUCTIONS
Do These Experiments With Adult Supervision Only!
1. Place candle in center of pie plate half full of water. (Water may be colored, if desired.)
2. Light candle and set a glass over the top. Observe what happens.
Explanation: Fire needs oxygen to burn. Once all of the oxygen is used up in the glass, the candle burns out. The resulting vacuum sucks the water from the pie plate up into the glass.
Puffy Soap Float
1. Gather various types of soap and a bucket filled halfway with water. Predict what will happen when the soap is put into the water.
2. Place a bar of Ivory soap in a microwaveable container and microwave on high for 2 min.
Explanation: Different types of soap vary in density. Some soap, like Ivory will float because it is less dense than water. Most other soaps are more dense and will sink. Two processes occur when you microwave the soap. First, you are heating the soap, which softens it. Second, you are heating the air and water trapped inside the soap, causing the water to vaporize and the air to expand. The expanding gases push on the softened soap, causing it to expand and become a foam. The appearance of the soap is changed, but no chemical reaction occurs. This is an example of a physical change. It also demonstrates Charles' Law, which states the volume of a gas increases with its temperature. The microwaves impart energy into the soap, water, and air molecules, causing them to move faster and further away from each other. The result is that the soap puffs up. Other brands of soap don't contain as much whipped air and simply melt in the microwave.
1. Disolve 1 teaspoon of yeast in 2 Tablespoons of very warm water.
2. Stand a 16 oz, narrow neck bottle in a cake pan. Put a funnel in the opening. Add 3-4 drops of food coloring to ½ c peroxide and pour the peroxide through the funnel into the bottle.
3. Add a squirt of dish detergent.
4. Pour the yeast mixture into the bottle and quickly remove the funnel.
- You can touch the bottle to feel any changes that take place.
Explanation: The bottle will feel warm to the touch as this is an exothermic reaction. The yeast works as a catalyst, which makes the peroxide molecule release an oxygen atom. The released oxygen mixes with the dish detergent to make foam.
Egg in a bottle
1. Light a strip of paper and drop into a glass bottle. Or pour a little very hot water into the bottle. Wait a moment.
2. Place peeled hard boiled egg on mouth of bottle. (Diameter of opening should be smaller than egg, but at least half the diameter of the egg.)
Explanation: This is just a variation of the water sucker experiment. How can you remove the egg without damaging it? (Hint: use tongs and hot water pouring from a tap.)
1. Fill 2 liter plastic soda bottle ¾ of the way with cooking oil.
2. Add water almost to top. Add about 10 drops of food coloring.
3. Add pieces of Alka Selter and put lid back on.
Explanation: This experiment demonstrates some science you already know...oil and water do not mix. Even if you try to really shake-up the bottle, the oil breaks up into small little drops, but the oil doesn't mix with the water. Food coloring only mixes with water. That's why it does not color the oil. In addition, the Alka-Seltzer reacted with the water to make tiny bubbles of carbon dioxide gas. These bubbles attached themselves to the blobs of colored water and cause them to float to the surface. When the bubbles popped, the color blobs sank back to the bottom of the bottle.
1. Pour milk into a cake or pie pan.
2. Drop drops of food coloring into milk.
3. Dip a q tip into dishwashing soap, then touch milk.
Explanation: Surfactants, or “surface active agents,” are substances like soap and detergent, which have specific chemical properties that affect the surface tension of a solution. Surface tension causes the surface layer of a solution to behave like a fragile elastic sheet. When a surfactant (such as detergent) is submerged in water, it, penetrates the ‘elastic sheet’ that exists at the top of any quantity of water. This causes a reduction in surface tension of the solution, as well as an emulsification (mixing together) of two incompatible substances, such as oil and water. This ability to emulsify is what allows soap and detergent to “wash away” fats, oils, and grime from hands, dishes, and other surfaces. Try using milks of different fat contents and observe the differences in reaction.
1. Put 1 c. of water into a bowl.
2. Slowly stir in 1.5 to 2 c of cornstarch. The amount needed will vary. Start with a spoon to stir and end with your hands!
Explanation: Oobleck is a non-newtonian fluid. That is, it acts like a liquid when being poured, but like a solid when a force is acting on it. You can grab it and then it will ooze out of your hands. Make enough Oobleck and you can even walk on it! Oobleck gets its name from the Dr. Seuss book Bartholomew and the Oobleck where a gooey green substance, Oobleck, fell from the sky and wreaked havoc in the kingdom.
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