Materials (per kid):

• 2 plastic cups
• Water
• Lemonade powder
• Lemon juice
• ⅛ tsp baking soda
• Spoon
• Measuring cups and spoons
• Knife

Instructions:

In one cup, mix together 1 cup of water with 1 spoon of lemonade powder.

Cut the lemon into 8ths.

Add around a teaspoon of lemon juice to the lemonade.

Add ⅛ tsp baking soda (half of ¼ teaspoon) and mix.

Taste your lemon soda!

Explanation:

Just like in the lemon volcano demo, an acid-base reaction occurs and the citric acid from the lemon juice and the basic baking soda work together to create a gas (the same gas, in fact, as in carbon dioxide!). Because this reaction takes place in the juice, some of this carbon dioxide gets trapped within the liquid. This is what makes the soda taste fizzy. You may notice that your drink tastes a bit salty; this is because baking soda has sodium in it – does anybody know what sodium chloride is? It’s table salt.

Note: It will take some time to inflate the balloon. Have the kids come back later.

Materials

• A packet of yeast (available in the grocery store)
• A small, clean, clear, plastic soda bottle (16 oz. or smaller)
• 1 teaspoon of sugar
• Some warm water (MUST BE WARM)
• A small balloon
• Electric kettle

Instructions:

Fill the bottle up with about one inch of warm water. (When yeast is cold or dry the micro organisms are resting.)

Add all of the yeast packet and gently swirl the bottle a few seconds. (As the yeast dissolves, it becomes active – it comes to life! Don’t bother looking for movement, yeast is a microscopic fungus organism.)

Add the sugar and swirl it around some more. Like people, yeast needs energy (food) to be active, so we will give it sugar. Now the yeast is “eating!”

Blow up the balloon a few times to stretch it out then place the neck of the balloon over the neck of the bottle.

Let the bottle sit in a warm place for about 20 minutes

If all goes well the balloon will begin to inflate!

Explanation:

As the yeast eats the sugar, it releases a gas called carbon dioxide as a waste product. The gas fills the bottle and then fills the balloon as more gas is created. We all know that there are “holes” in bread, but how are they made? The answer sounds a little like the plot of a horror movie. Most breads are made using YEAST. Believe it or not, yeast is actually living microorganisms! When bread is made, the yeast becomes spread out in flour. Each bit of yeast makes tiny gas bubbles and that puts millions of bubbles (holes) in our bread before it gets baked. Naturalist’s note – The yeast used in this experiment are the related species and strains of Saccharomyces cervisiae. (I’m sure you were wondering about that.) Anyway, when the bread gets baked in the oven, the yeast dies and leaves all those bubbles (holes) in the bread. Yum.

Notes: The kids need to throw the whirlybirds VERY high into the air – encourage them to throw it as hard as possible. You can also keep the wings folded down and throw it up. It will still fly. If you can access the second/third story of a building it’s fun to drop the whirlybirds from there and watch them spin to the ground.

Materials:

• Paper clips
• Paper with template: https://www.sciencebuddies.org/Files/15270/9/whirlybird-template-new.pdf
• Regular paper
• Scissors

Instructions

Cut out and fold the whirlybird according to the template.

First toss the whirlybird up without anything weighing it down.

Then add a paper clip to the bottom – notice the difference?

Experiment with different paper clip weights, lengths/widths of the propeller wings, etc. Have a little competition to see who can make the best design that flies the longest!

Explanation:

Helicopters stay in the air using spinning blades that are used to generate an upwards push called "lift." With enough of it, a craft can overcome the force of gravity, which pulls the object down toward Earth. Aircrafts such as helicopters with spinning blades are called rotary wing, unlike traditional airplanes, which are fixed wing.

How do helicopters fly? (cont)

Helicopters’ rotors push air down, creating a difference in air pressure that creates lift. The faster the rotors spin, the greater the difference in air pressure. The greater the difference in air pressure, the more the lift, and the higher the helicopter can fly.

How do our whirlybirds work?

Just like a helicopter, our whirlybirds rely on lift. This lift is generated from the difference in pressure between the air below the rotors of the helicopter and the air above the helicopter rotors. Our whirlybirds don’t have enough lift to overcome gravity. However, they do have enough lift to slow their descent towards the ground.

Description: In this activity, students will learn about non-Newtonian fluids and viscosity.

Materials:

• Cornstarch
• Water
• Cup
• Spoon

Directions

Pour about one cup of cornstarch into the mixing bowl, and dip your hands into it.

Pour the water in, mixing slowly as you go. Keep adding more water until the mixture becomes thick (and hardens when you tap on it). Add more cornstarch if it gets too runny, and more water if it becomes too thick.

Drop your hands quickly into the Oobleck - take note of what happens slowly lower your hands into it. Notice the difference!

Hold a handful in your open palm—what happens?

Try squeezing it in your fist or rolling it between your hands—how does it behave differently?

Move your fingers through the mixture slowly, then try moving them faster.

Explanation:

Oobleck can mimic the qualities of a solid or liquid. These materials are called Non-newtonian fluids. While a Newtonian fluid has a constant viscosity (example: water has a constant viscosity), the viscosity of Non-newtonian fluids changes. You can think of viscosity as fluidity, or how thick a fluid is. For example, syrup has a high viscosity while water has a lower viscosity.

Can you think of more examples of high viscosity fluids? What about low viscosity fluids?

Back to oobleck. The viscosity of oobleck changes depending on the force exerted on it over time. Strong forces exerted over little time cause the oobleck to have a high viscosity. This is because the cornstarch particles are being governed by the forces of friction, which make it hard for them to move against each other. This in turn increases the viscosity. However, when weaker forces are exerted on the oobleck, it acts more like a liquid.

Description: In this activity, students will learn about chromatography and how it is used to separate mixtures of substances into their components based on small differences in solubility of different molecules.

Materials:

• White Coffee Filters
• Pencils OR Pens
• Scissors
• Water Based Markers
• Tape
• Cup
• Water
• Towels OR Paper Towels

Directions:

Open the coffee filter and make a design as desired with markers. Make sure the marker ink bleeds through the coffee filter.

Fill the Cup With Just Enough Water to Submerge the Bottom Center of the Filter.

Place the Decorated Filter Into the Cup With the Middle Touching the Water.

Watch the Water Move Upwards. Wait for around 5 minutes.

Take your chromatography flower out of the cup and let it dry.

Fold the filter into fourths and cut off the top to make a petal design.

Explanation:

Chromatography is used to separate mixtures of substances into their components based on small differences in solubility of different molecules. Molecules that are the most soluble will move the furthest and the least soluble will travel the shortest and are measured in retention time. The water itself is able to move up the paper due to the properties of water creating capillary action.

Determining the components of a mixture are important because it allows scientists to know what is in a mixture and how to recreate it (such as in medicine if a new mixture is found in nature) or how to alter it (such as if a mixture is toxic to people, chromatography can help determine what is making it toxic).