Hey there! Have you ever played with LEGOs? Did you know they can help us learn about science? Today, we’re going to explore a cool science idea called the conservation of mass using LEGOs and some fun experiments!
The conservation of mass is a rule that says mass is never created or lost. This means that when you put things together or take them apart, the total mass stays the same. For example, if you measure the mass of each LEGO piece separately and then build something like a dinosaur, the mass of the dinosaur will be the same as the mass of all the pieces combined.
We can see the conservation of mass in action during both physical and chemical changes. Physical changes are when things change form but not what they’re made of, like mixing a solution. But what about chemical changes, like when we bake a cake?
During chemical changes, the particles that make up substances rearrange to form new substances. There are clues that a chemical change is happening, like a change in temperature, bubbling, or even a flash of light!
In a chemical reaction, the substances you start with are called reactants. These are the particles that get rearranged. The new substance that is formed is called the product. Let’s use LEGOs to understand this better!
Imagine you have some LEGO cubes. If you take them apart, mix them up, and build something new, you have your product. Even though it looks different, it’s made of the same LEGOs as before. So, the mass of this new product is the same as the original cubes. This shows that mass is conserved!
Now, let’s try an experiment with vinegar and cream. First, we measure the mass of each liquid and write it down. Then, we mix them together. It might look gross, but it’s a great example of the conservation of mass. The mixture creates a new substance called curds, which is a solid product. The mass of the curds is the same as the mass of the vinegar and cream combined.
Even if a chemical reaction creates a gas, like when vinegar and baking powder make bubbly foam, the mass is still conserved. Gas is matter and has mass, too. So, no matter what state the products are in, the total mass of the products will always equal the total mass of the reactants.
Whether it’s a physical or chemical change, the conservation of mass holds true. Matter can’t be created or disappear. It’s always conserved! Now that we’ve learned about this scientific rule, it’s time to have some fun and build a velociraptor with LEGOs!
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LEGO Weighing Challenge: Gather a small set of LEGO pieces and a kitchen scale. Weigh each piece individually and write down their masses. Then, build a simple structure, like a small house or car, using all the pieces. Weigh the completed structure and compare it to the total mass of the individual pieces. Discuss with an adult or friend why the mass stayed the same, reinforcing the concept of the conservation of mass.
Kitchen Chemistry Exploration: With the help of an adult, try mixing baking soda and vinegar in a clear container. Before mixing, weigh the container with the baking soda and vinegar separately. After mixing, observe the bubbling reaction and weigh the container again. Discuss how the mass remains the same even though a gas is produced, emphasizing that gas has mass too.
Observation Walk: Go on a walk around your home or garden and look for examples of physical and chemical changes. For example, melting ice (physical change) or rusting metal (chemical change). Take notes or draw pictures of what you see. Discuss how the conservation of mass applies to these changes, and think about what the reactants and products might be in each case.
