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Understand the difference between atoms that are stuck together and atoms that are just hanging out.
Have you ever wondered why you can easily pick the raisins out of your trail mix, but you can't pick the 'sweet' out of a grain of sugar? It all comes down to how atoms decide to hang out together!
Imagine a toy box filled with LEGOs, marbles, and action figures. Even though they are all in the same box, the marbles are still marbles and the LEGOs are still LEGOs. This is a mixture. In a mixture, different substances are put together, but they don't actually change into something new. They are just 'hanging out' in the same space. You can usually separate them pretty easily, just like picking the pretzels out of a bowl of snacks. The atoms in a mixture are like friends standing in a group—they are close to each other, but they aren't holding hands or glued together!
1. Take a bowl of cereal and add some dried strawberries. 2. Stir them together with a spoon. 3. Notice that the cereal is still crunchy and the strawberries are still sweet. 4. If you wanted to, you could use your fingers to put all the strawberries in a separate pile. This is a classic mixture!
Quick Check
If you stir sand into a bucket of water, is it a mixture or a compound?
Answer
It is a mixture because the sand and water stay as separate things and can be filtered apart.
Now, imagine taking those LEGOs and super-gluing them together to build a tiny house. You can't just shake the box to get the pieces apart anymore! A compound happens when different types of atoms 'snap' together using something called a chemical bond. When atoms bond, they actually change! They stop acting like separate pieces and start acting like a brand-new substance. For example, the salt on your fries is a compound called Sodium Chloride, written as . It is made of Sodium (a dangerous metal) and Chlorine (a smelly gas), but when they bond, they turn into delicious, safe salt!
Think about baking a cake. 1. You mix flour, eggs, and sugar (this starts as a mixture). 2. You put it in the oven (adding heat helps the atoms bond). 3. When the cake comes out, it is a new substance. You can't 'un-bake' it to get the eggs back! 4. While a cake is more complex, it shows how things change when they truly combine into something new.
Quick Check
What is the name of the 'glue' that holds atoms together in a compound?
Answer
A chemical bond.
You are surrounded by compounds every day! Two of the most famous ones are in your kitchen: Salt and Sugar. Table salt is , which means it has one atom of Sodium for every one atom of Chlorine. Sugar is a bit more complex. The sugar you put on cereal is called Sucrose, and its formula is . This means it has 12 Carbon atoms, 22 Hydrogen atoms, and 11 Oxygen atoms all bonded together. Even though it's made of many parts, it acts like one single, sweet substance because those atoms are locked tight in a compound.
1. The air around you is a mixture. It has Oxygen () and Nitrogen () floating around together, but they aren't stuck to each other. 2. Water is a compound (). Two Hydrogen atoms are chemically bonded to one Oxygen atom. 3. Because water is a compound, it behaves totally differently than the gases it is made of!
Which of these is the best example of a mixture?
In the compound , what does the 'bond' do?
Sugar is a compound made of Carbon, Hydrogen, and Oxygen atoms.
Review Tomorrow
Tomorrow morning, look at your breakfast. Can you find one thing that is a mixture and one thing that is a compound?
Practice Activity
Try the 'Separation Test': If you can separate the parts of your lunch using just your hands or a spoon, it's a mixture!