Tommy and Suzy (brother and sister) went to the playground one afternoon with their mom and dad, Jan and Dean. They were playing a game of tag and having the best time ever running after each other and laughing. They liked to play tag instead of building sandcastles or swinging. They liked tag because they liked to run. They like to play hopscotch or jump rope but that day they wanted to play tag. Other games aren't as fun. They met Tony and Ally (who are best friends) and invited them to play tag too. Tony and Ally like to play other games like hopscotch or jump rope but that day they joined the game of tag. Making new friends is important. Tony and Ally would rather make friends than play their favorite games.

Who invited Tony and Ally to play tag?

Rough surfaces create more friction than smooth surfaces. Thats why cars have tires. Its also why we use rubber mats in areas that might get wet. In your bathtub, you may even use No-Slip tape. No-slip is another way of saying the items has a lot of friction. In Figure 1.9, the blades of the skates are very smooth. Thats why you cant slide across ice with shoes. The soles of your shoes are much rougher than skates. The rougher surface of shoes causes more friction and slows you down. Heavier objects also have more friction. A heavy object presses down with more force. The surfaces are held together more tightly. This makes the surfaces harder to slide past each other. Did you ever try to push something heavy across the floor? Heavy objects are much harder to push than light objects.

Do ice skates provide much friction?

Physical properties include the state of matter. We know these states as solid, liquid, or gas. Properties can also include color and odor. For example, oxygen is a gas. It is a major part of the air we breathe. It is colorless and odorless. Chlorine is also a gas. In contrast to oxygen, chlorine is greenish in color. It has a strong, sharp odor. Have you ever smelled cleaning products used around your home? If so, you have probably smelled chlorine. Another place you might smell chlorine is at a public swimming pool. The chlorine is used to kill bacteria that may grow in the water. Other physical properties include hardness, freezing, and boiling points. Some substances have the ability to dissolve in other substances. Some substances cannot be dissolved. For example, salt easily dissolves in water. Oil does not dissolve in water.
Which gas is found in cleaning products?